CN111615581A

CN111615581A - Profile selective sleeve for underground multistage valve actuation

Info

Publication number: CN111615581A
Application number: CN201780098176.7A
Authority: CN
Inventors: 肖恩·P·坎贝尔; 丹尼尔·罗加斯
Original assignee: Sc Assets Ltd
Current assignee: Sc Assets Ltd
Priority date: 2017-11-21
Filing date: 2017-11-21
Publication date: 2020-09-01
Anticipated expiration: 2037-11-21
Also published as: CN115898330A; RU2020119145A; ECSP20032779A; AU2017440345A1; CN111615581B; MX2020005301A; WO2019100139A1; RU2020119145A3

Abstract

A spool valve has a valve body, a sliding sleeve received in a longitudinal bore of the valve body, and a collet received in a longitudinal bore of the sliding sleeve. The valve body has one or more fluid ports on a wellhead portion of a sidewall thereof. The sliding sleeve is movable between an uphole closed position closing the one or more fluid ports and a downhole open position opening the one or more fluid ports. The sliding sleeve has a sleeve contour formed at least by one or more sleeve grooves and one or more sleeve ridges distributed longitudinally on its inner surface. The collet has a flexible collet profile formed by at least one or more collet grooves and one or more collet ridges corresponding to the sleeve grooves and the sleeve ridges, respectively. The length of each sleeve ridge or collet ridge is less than the length of the corresponding sleeve groove or collet groove.

Description

Profile selective sleeve for underground multistage valve actuation

Technical Field

The present disclosure relates generally to downhole tools and methods, and more particularly to a downhole tool having a profile selective casing for subsurface multistage valve actuation.

Background

Downhole tools have been widely used in the oil and gas industry. Many downhole tools include pressure actuated valves. For example, prior art ball actuated slide valves include a tubular valve housing having an aperture and receiving a sliding sleeve therein. The sliding sleeve includes a ball seat at an uphole end thereof and is initially configured in an uphole closed position blocking one or more fluid ports on a sidewall of the valve housing. To actuate the slide valve, it is necessary to drop and seat the ball on the ball seat of the slide sleeve. Fluid pressure is then applied to the ball to actuate the sliding sleeve downhole to an open position to open a fluid port in the valve housing.

One or more ball actuated spool valves may be used during a fracturing process to fracture a subterranean formation. However, one problem with cascading multiple ball actuated spool valves for fracturing is that the bore of the downhole spool valve must be smaller than the bore of the uphole spool valve to allow smaller sized balls to pass through the uphole spool valves to the target downhole spool valve. In other words, the bore of the spool valve cascade must decrease in order from uphole to downhole to ensure successful operation, which results in a decrease in flow at the downhole end.

United states patent 4,043,392 to Gazda teaches a well system for selectively locking a downhole tool along a flow conduit in a wellbore, and a tool string for use in the flow conduit, the tool string including a locking mandrel, a casing displacement device, and a well safety valve. The selective locking system has a seating and locking recess profile including upward and downward facing stop shoulders. One form of lockout system is disposed in a sliding sleeve valve that includes a cam release shoulder to release the selector and the lockout key when the sliding sleeve valve is moved between the spaced apart longitudinal positions. Another form of locking system may be disposed along the setting sub and requires disabling the drilling tool locked therein to release the selector and locking tool. The casing shifting device has means for opening and closing a sliding sleeve valve comprising a key with an upward and downward stop shoulder and a recess profile compatible with the landing and locking recess profiles of a casing valve or landing nipple. The cannula displacement device may also be used as a locking mandrel. The selectivity is provided by variations in the seating and locking profiles and the profiles of the keys.

In US 4,043,392, the profiles of the spring biased keys are mutually exclusive. The profile of the key will only engage with a sliding sleeve having a matching internal profile.

U.S. patent 4,436,152 to Fisher et al teaches an improved shifting tool that is attachable in a well tool string and that can be used to engage and position a sliding sleeve in a well flow conduit in a sliding sleeve device. The selectively shaped shifting tool key provides a better fit and a larger contact area between the key and the sliding sleeve. When the engaged sliding sleeve cannot be moved upward and the shifting tool cannot be automatically disengaged, the shifting tool can be removed from the sliding sleeve device by applying an emergency disengagement means to the shifting tool sufficient to shear the keys and cam both ends of all keys inward to achieve complete disengagement.

U.S. patent 5,305,833 to coriins teaches a shifting tool for a sliding sleeve valve used in oil and gas wells having a locating pawl for selectively locating and engaging a shoulder in the valve. The primary key engages and selectively displaces the sliding sleeve to an equilibrium position and prevents premature displacement to a fully open position. The shifting tool also includes means for selectively overriding the anti-shifting function after balancing. The auxiliary key guides the main key in the displacement direction and engages the sleeve and moves the sleeve to the fully open chucking position. The shifting tool may also be selectively disengaged from the casing valve to withdraw the shifting tool from the well. Additionally, a method for selectively and sequentially moving a sleeve of a sleeve valve from a closed position to an equilibrium position and then from the equilibrium position to a fully open position is disclosed.

In particular, US 5,305,833 teaches two independent spring biased keys, wherein a first of the two keys may fit in the profile of the second key. But the second key cannot fit within the outline of the first key.

U.S. patent 5,309,988 to summer (Shy) et al teaches a subterranean well flow control system that includes a series of movable casing-type flow control devices mounted in a well flow conduit at a plurality of fluid-containing fracture zones, and a shifting tool movable in the conduit and operable to selectively move the casing portions of any selected number of flow control devices in either direction between their open and closed positions without removing the tool from the conduit. Sets of radially retractable anchor and indexing keys are provided in the sidewall opening of the tool body and are configured to lockingly engage sets of inner side surface grooves on the body and movable sleeve portions, respectively, of any one of the flow control devices. The key sets are biased radially outwardly toward the extended position by springs, and an electro-mechanical drive system disposed within the tool body is operable to radially retract the key sets and axially drive the shift key sets toward or away from the anchor key sets. This allows the tool to be moved in either axial direction into or through either of the flow control devices, locked to the device, operated to move its sleeve portion fully or partially in either direction, and then disengaged from the flow control device and moved to any other one of the flow control devices to displace its sleeve portion. The interengaging V-shaped threads on the body and the sleeve portion of each flow control device help releasably retain the sleeve portion in the partially displaced position.

US 5,309,988 also teaches two mutually exclusive key profiles.

United states patent 5,730,224 to Williamson et al teaches a subterranean formation for controlling tools into and out of a horizontal wellbore extending from the wellbore. The subterranean structure includes a liner positioned in the wellbore adjacent to the opening of the horizontal wellbore and having an access window therethrough to allow tools to access the horizontal well through the opening. The bushing also has a sliding in and out control coaxially coupled thereto. The subterranean structure further includes a shifting device engageable with the sliding access control device to slide the sliding access control device between an open position to allow tools to pass through the window and opening and into the horizontal wellbore and a closed position to prevent tools from passing through the window and opening into the horizontal wellbore. The patent also teaches a method of controlling access of tools to and from a horizontal wellbore extending from the wellbore. The preferred method comprises the steps of: 1) positioning a liner in the wellbore proximate an opening of the lateral wellbore, the liner having an access window therethrough to allow access to the lateral wellbore by a tool through the opening, the liner further having a sliding access control device coaxially coupled thereto; 2) engaging the slide in and out control with the displacement device to slide the slide in and out control relative to the bushing; and 3) sliding the sliding access control device between an open position to allow the tool to pass through the window and opening and into the horizontal wellbore and a closed position to prevent the tool from passing through the window and opening and into the horizontal wellbore.

US 5,730,224 teaches two key profiles, one of which is the opposite of the other.

Us patents 7,325,617 and 7,552,779 to Murray teach a system that allows for sequential processing of segments of a region. Each section can be accessed with a sliding sleeve having a specific internal profile. A pumping plug having a specific profile that enables it to latch onto a specific sleeve may be used. When in the latched state, pressure on the plug allows sequential opening of the sleeves while isolating the area below that which has been affected. The pump plug has a passage that is initially blocked by material that eventually disappears under expected well conditions. Thus, when all portions of the area have been processed, the flow path is re-established by the respective latch plugs. The plug may also be blown off the sliding sleeve after it has been manipulated and may have a key which prevents the plug from rotating along its axis when it is later required to mill the plug.

Us patent 9,611,727 to Campbell et al teaches an apparatus and method for fracturing a well in a hydrocarbon containing formation. The apparatus includes a valve subassembly assembled with a casing segment to form a well casing for the well. The valve subassembly includes a sliding piston that is fixed in position to seal a port that provides communication between the interior of the wellbore and a production zone of the formation. A dart with a cup seal can be inserted into the wellbore and pushed through the pressurized fracturing fluid until the dart reaches the valve subassembly to plug the wellbore below the valve subassembly. The force of the fracturing fluid on the dart and its cup seal forces the piston to move downward to shear the pin and open the port. The fracturing fluid may then flow out of the ports, thereby fracturing the production zone of the formation.

U.S. patent 9,739,117 to Campbell et al teaches a method and apparatus for selectively actuating a downhole tool in a tubular conduit. The actuator tool has an actuator mandrel with an actuator bore, a bypass, and a profile key for selectively engaging the downhole tool. The downhole tool has one or more profile receivers adapted to actuate the downhole tool. If the profile key matches the profile receiver, the actuator tool is conveyed into the tubular conduit and the actuator tool engages the downhole tool; if the profile key does not match the profile receiver, the actuator tool and the downhole tool cannot be engaged. Fluid may be circulated through the actuator bore to flush or clean prior to the actuator tool.

U.S. patent publication 2003/0173089 to Westgard teaches a full bore selective positioning and orientation system including a sub mountable in a pipe string and having an internal location and orientation configuration of known construction, and a positioning device operable within the pipe string and having a location and orientation configuration engageable with the internal configuration of the sub. A method of locating and orienting a downhole tool comprising installing a tubular sub having a particular inner dimensional configuration in a tubular string running a locating device having a complementary outer dimensional configuration to engage the inner dimensional configuration and rotate the locating device to a position in which a biasing member extends from the locating device into a recess in the tubular member.

U.S. patent publication 2015/0226034 to Jani (Jani) teaches an apparatus and associated method for selectively actuating a sliding sleeve in a downhole sub-member in a wellbore to open ports in such sub-member to allow fracturing of the wellbore or detonation of explosives thereon, or both. Simplified darts and sleeves are used, which reduces the machining operations on each part. The dart is preferably provided with coupling means to facilitate coupling of a retrieval tool thereto, allowing the bypass valve to operate to assist withdrawal of the dart from within the valve adaptor when the retrieval tool is so coupled. Upward movement of the retrieval tool allows a wedge member to disengage the dart member from the corresponding sleeve to withdraw the dart.

U.S. patent publication 2014/0209306 to houses et al teaches a wellbore treatment tool for use against a confining wall into which the wellbore treatment tool is positionable. The wellbore treatment tool includes a tool body including a first end formed to be connected to a tubing string and an opposite end; a stop key assembly comprising a tubular housing defining an internal bore extending along a length of the tubular housing and an outwardly facing surface with a stop key, the stop key configured to lock the stop key and the tubular housing in a fixed position relative to the constraining wall, the tubular housing being sleeved over a tool body mounted in the internal bore of the tubular housing; and a sealing element surrounding the tool body and located between a first compression ring on the tool body and a second compression ring on the tubular housing, the sealing element being expandable to form an annular seal around the tool body by compression between the first compression ring and the second compression ring.

U.S. patent publication 2015/0218916 to Richards et al teaches a circulating casing that can be opened and closed as well as permanently closed. A completion system includes a completion string having a circulating sleeve movably disposed therein, the circulating sleeve having a locking profile defined on an outer radial surface thereof and a shifting profile defined on an inner radial surface thereof, and a service tool disposed at least partially within the completion string and including a shifting tool having one or more shifting keys configured to mate with the shifting profile. When the shifting key locates and engages the shifting profile, an axial load applied to the service tool axially displaces the circulating casing, a release shoulder assembly is disposed within the completion string and includes a release shoulder defining a passage configured to receive the locking mechanism blocked therein until the release shoulder is axially displaced.

Canadian patent 2,412,072 to fel (Fehr) et al teaches a tubing string assembly for fluid treatment of a wellbore. The string may be used for staged wellbore fluid treatment, in which selected portions of the wellbore are treated while other portions remain sealed. The string may also be used in situations where it is desired to run a ported string in a pressure sealed condition and then use it with the port open.

The fracturing industry is constantly interested in alternative and/or improved designs that enable subterranean valves to consistently and reliably engage and actuate and improve sealability.

Disclosure of Invention

According to one aspect of the present disclosure, a plurality of spool valves is provided. Each spool valve includes:

-a valve body having a longitudinal bore therethrough and one or more fluid ports located on a wellhead portion of a sidewall of the valve body; and

-a sliding sleeve received in the longitudinal bore of the valve body and movable between an uphole closed position closing the one or more fluid ports and a downhole open position opening the one or more fluid ports, the sliding sleeve comprising a longitudinal bore;

wherein the sliding sleeve comprises a sleeve profile formed by at least a first and a second sleeve groove and a sleeve ridge therebetween, the first and second sleeve grooves and the sleeve ridge being longitudinally distributed on an inner surface of the sliding sleeve; and is

Wherein the longitudinal lengths S of the first and second ferrule grooves and the ferrule ridge_g1、S_g2And S_rAre respectively determined by the following formula:

S_r＝L_a+nL_b,

S_g1＝m₁L_b+(1-)L_a,

S_g2＝m₂L_b,

m₁+m₂＝K,

wherein L is_a、L_bAnd is a predetermined parameter, L_a>0，L_b>0 and 1 is not less than 0, n is an integer and n is not less than 0, K is a positive integer and K>2，m₁And m₂Is an integer and m₁M is not less than 1₂>1; and is

Wherein the longitudinal length L of the casing profile_sAt least:

L_s＝L_a+(n+K)L_b.

in some embodiments, the spool valve further comprises a stop shoulder.

In some embodiments, the stop shoulder is located downhole of the casing profile.

In some embodiments, the stop shoulder is located in the cannula profile.

In some embodiments, the stop shoulder is located on the uphole side of the casing profile.

In some embodiments, L_a＝L_b。

In some embodiments, t₁＝t₂＝t。

In some embodiments, 1> t > 0.

In some embodiments, t is about 0.5.

In some embodiments, 0.9> t ≧ 0.1.

In some embodiments, 0.8> t ≧ 0.2.

In some embodiments, 0.7> t ≧ 0.3.

In some embodiments, 0.6> t ≧ 0.4.

In some embodiments, t is 0.

In some embodiments, t is 1.

According to one aspect of the present disclosure, a plurality of collets are provided, each collet being movable through a bore of one or more first runners and receivable in a second runner. Each chuck includes:

a flexible collet profile formed by at least first and second collet ridges and collet slots therebetween, the first and second collet ridges and collet slots corresponding to the first and second sleeve slots and sleeve ridges, respectively;

wherein the first and second collet ridges and collet grooves have a length C_r1、C_r2And C_gAre respectively determined by the following formula:

C_r1＝(m₁-t₁)L_b+(1-)L_a-₂,

C_r2＝(m₂-t₂)L_b,

C_g＝L_a+(n+t₂)L_b+₂,

m₁+m₂＝K,

wherein L is_a、L_bAnd is a predetermined parameter, L_a>0，L_b>>0 and 1 is not less than 0, n is an integer and n is not less than 0, K is a positive integer and K>2，m₁And m₂Is an integer and m₁M is not less than 1₂>1；t₁、t₂And₂is a predetermined parameter, 1 ≧ t₁≥0，1≥t₂Is not less than 0 and₂not less than 0; and is

Wherein the longitudinal length L of the collet profile_cAt least:

L_c＝L_a+(n+K-t₂)L_b.

in some embodiments, at least one of the at least one collet ridge is located downhole of the stop shoulder and forms an obtuse angle between upper edges of its downhole side.

According to one aspect of the present disclosure, there is provided a tubular string comprising a plurality of the above-described spool valves having 1> t > 0;

wherein the slide valves are arranged in the pipe column according to the following rules:

(a) for any two of the plurality of spools, n, K, and m₁Is different;

(b) the spool valve with the smaller (n + K) is located on the wellhead side of the spool valve with the larger (n + K);

(c) for a spool valve with the same (n + K), the spool valve with the larger value of n is located on the wellhead side of the spool valve with the smaller value of n; and is

(d) Having the same n and the same K but different m₁The spools of (a) may be arranged in any order.

According to an aspect of the present disclosure, there is provided a pipe string including: a plurality of the above-described spool valves having t ═ 1;

(a) for any two of the plurality of spools, n, K, and m₁Is different;

(b) for any two of the multiple spools with the same n and the same K, m is₁The difference between them is greater than 1;

(c) the spool valve with the smaller (n + K) is located on the wellhead side of the spool valve with the larger (n + K);

(d) for a spool valve with the same (n + K), the spool valve with the larger value of n is located on the wellhead side of the spool valve with the smaller value of n; and is

(e) Having the same n and the same K but different m₁The spools of (a) may be arranged in any order.

In some embodiments, the tubular string is a casing string.

In some embodiments, the tubing string is a tubing string for receipt in a cased or uncased wellbore.

According to an aspect of the present disclosure, there is provided a downhole system comprising: said string including a plurality of said spools having 1> t > 0; and one or more of the above-described chucks.

Drawings

Further advantages and other embodiments of the invention will now become apparent from reading the above description and the following detailed description of several specific embodiments of the invention, given with reference to the accompanying drawings, each of which is non-limiting, in which:

FIG. 1 is a cross-sectional view of a downhole tool in the form of a spool valve including a valve body and a sliding sleeve movable in the spool valve with the sliding sleeve configured in a closed position, further illustrating a protective sleeve used in accordance with some embodiments of the present disclosure;

FIG. 2 is a cross-sectional view of the valve body of the downhole tool shown in FIG. 1 without the protective sleeve;

FIG. 3 is a cross-sectional view of the sliding sleeve of the downhole tool shown in FIG. 1, showing an additional protective sleeve;

FIG. 4 is a cross-sectional view of the sleeve body of the sliding sleeve shown in FIG. 3;

FIG. 5 is a cross-sectional view of the sliding sleeve protective sleeve of FIG. 3;

FIG. 6 is a cross-sectional view of the stop ring of the sliding sleeve shown in FIG. 3;

FIG. 7 is an exploded cross-sectional view of the sliding sleeve of FIG. 3 illustrating the process of assembling the sliding sleeve;

FIG. 8 is a cross-sectional view of a collet for actuating the mating spool valve shown in FIG. 1;

FIGS. 9-12A are cross-sectional views of the collet of FIG. 8 and the mating spool valve of FIG. 1, illustrating the process of the collet entering into and lockingly engaging the mating spool valve;

FIG. 12B is an enlarged cross-sectional view of a portion of FIG. 12A, showing the profile areas of the collet and mating spool valve when the collet is lockingly engaged in the mating slide sleeve;

FIG. 13 is a schematic cross-sectional view showing the collet of FIG. 8 locked into the mating slide valve of FIG. 1 and a ball dropped into the slide valve to actuate the slide valve to an open position;

FIG. 14 is a schematic cross-sectional view showing the sliding sleeve of the sliding valve shown in FIG. 13 actuated by ball and collet pressure to an open position to open fluid ports for fracturing;

FIG. 15A is a schematic cross-sectional view showing the sliding sleeve of an alternative embodiment of a sliding valve actuated by ball and collet pressure to an open position to open a fluid port for fracturing, wherein upon application of wellhead fluid pressure, the splines of the collet can be pressure actuated to expand radially outward, and compression of the collet causes the splines to expand radially outward to further engage the sliding sleeve to enhance engageability and thereby further enhance pressure resistance;

FIG. 15B is an enlarged cross-sectional view of a portion of FIG. 15A, showing the collet radially outwardly expanded in engagement with the sliding sleeve;

FIG. 16 is a schematic illustration of a casing string having a plurality of the spool valves of FIG. 1 extending into a wellbore to fracture a subterranean formation according to some embodiments of the present disclosure;

FIG. 17A is a cross-sectional view of a collet of some alternative embodiments;

FIG. 17B is an enlarged cross-sectional view of a portion of FIG. 17A, showing the ball seat of the collet;

FIG. 18 illustrates, in cross-section, one particular example of the collet of FIG. 17A received in the sliding sleeve of FIG. 3 and a ball received therein, the ball configured to expand radially outward in an expandable metal portion of the collet to form a metal-to-metal seal between the collet and the sliding sleeve upon seating the ball on a ball seat of the collet and applying well fluid pressure to the ball;

FIG. 19 is a cross-sectional view of a collet of some alternative embodiments;

20A-20D are schematic diagrams illustrating a plurality of sleeve profiles and their corresponding collet profiles of some alternative embodiments;

FIG. 21A is a schematic diagram showing the sleeve profile and corresponding collet profile to illustrate parameters related to the design of these profiles;

FIG. 21B is a schematic view showing the mating of the sleeve profile with the collet profile;

FIG. 21C is a schematic diagram showing the collet profile and the sleeve profile shown in FIG. 21B, with the collet profile received in the sleeve profile;

figures 22-49 are schematic views showing various designs of the sliding sleeve and collet profile areas;

FIG. 50 is a schematic diagram illustrating one example of a tubular string having a plurality of spool valves of some embodiments of the present disclosure;

FIG. 51 is a schematic view showing a set of expanded casing profiles and collet profiles of some alternative embodiments of the present disclosure;

FIG. 52 is a schematic view showing a set of expanded casing profiles and collet profiles of further alternative embodiments of the present disclosure;

FIG. 53 is a schematic view showing a set of expanded casing profiles and collet profiles of further alternative embodiments of the present disclosure;

figures 54-57 are schematic diagrams illustrating a set of expanded casing profiles and collet profiles of some other embodiments of the present disclosure;

figures 58-61 are schematic diagrams illustrating a set of expanded casing profiles and collet profiles of still other embodiments of the present disclosure;

FIG. 62 is a schematic view showing a set of expanded casing profiles and collet profiles of still other embodiments of the present disclosure; and

figures 63A-63F are schematic diagrams showing the collet profile on the collet and the casing profile on the sliding sleeve of some embodiments, wherein upon application of well head fluid pressure, the splines of the collet can be pressure actuated to expand radially outward, and compression of the collet causes the splines to expand radially outward, further engaging the sliding sleeve to enhance the engageability and thereby further enhance the pressure resistance.

Detailed Description

Embodiments herein disclose a spool valve that is actuatable by pressure. In the description that follows, the term "downhole" refers to a direction along a wellbore toward the end of the wellbore, and may or may not coincide with a "downward" direction (e.g., in a vertical wellbore) or (e.g., in a horizontal wellbore). The term "wellhead" refers to a direction along the wellbore toward the surface, and may or may not coincide with an "upward" direction (e.g., in a vertical wellbore) or (e.g., in a horizontal wellbore).

In some embodiments, the spool valve includes a valve body having a longitudinal bore and one or more fluid ports on a sidewall thereof. A sliding sleeve is received in the bore and is movable between an uphole closed position blocking the fluid port and a downhole open position opening the fluid port.

The sliding sleeve includes a contoured region on an inner surface thereof, the contoured region including circumferential grooves and ridges that form a contour of the sleeve. The contoured region includes a stop shoulder at its downhole end for locking a collet member (also referred to as a "collet" for ease of description) having a matching collet contour on its outer surface. Herein, the term "match" refers to a condition in which the collet profile of the collet matches the sleeve profile of the sliding sleeve such that the profile area of the collet can be received in the profile area of the sliding sleeve to lock the collet in the sliding sleeve of the sliding valve.

In some embodiments, the uphole surface of the stop ring slopes radially inward from downhole to uphole, forming a stop shoulder 194 having an acute angle α relative to the longitudinal axis of the stop ring.

In some embodiments, the stop shoulder is formed by a stop ring adjacent to a contoured region of the sliding sleeve.

In some embodiments, the stop ring is made of a high strength material, such as tungsten carbide, cobalt chrome, and/or the like.

In some embodiments, the collet is in the form of a cage and includes an uphole portion, a downhole portion, and a plurality of longitudinal splines mounted to the uphole and downhole portions at longitudinally opposite ends thereof. One, more or all of the longitudinal splines are flexible and shaped to form a collet profile.

In some embodiments, the wellhead portion of the collet includes a ball seat for receiving a ball from the wellhead to actuate the spool valve.

In some embodiments, the collet includes a metallic wellhead portion that is radially outwardly expandable such that when the collet is received in a mating spool valve and a ball is seated on a ball seat of the collet, fluid pressure exerted on the ball may force the expandable wellhead portion to radially outwardly expand and exert pressure on an inner surface of the sliding sleeve, thereby forming a metal-to-metal seal at an interface between the sliding sleeve and the collet.

In some embodiments, the ball seat of the collet includes an inclined surface.

In some embodiments, the inclined tee surface has an angle of inclination θ of about 55 ° relative to the longitudinal reference line. In some embodiments, the tilt angle θ is about 35 °. In some alternative embodiments, the tilt angle θ is about 50 ° to about 60 °. In some alternative embodiments, the tilt angle θ is about 40 ° to about 70 °. In some alternative embodiments, the tilt angle θ is about 30 ° to about 80 °.

Turning to FIG. 1, a downhole tool is shown and is generally identified by reference numeral 100. In these embodiments, the downhole tool 100 is in the form of a downhole spool valve and includes a tubular valve body 102 having a longitudinal bore 104 and a sliding sleeve 106 received in the bore 104. Sliding sleeve 106 is locked in a closed position of the wellhead by one or more shear pins 108 to close one or more fluid ports 110 on tubular body 102, and sliding sleeve 106 includes a longitudinal bore for receiving a mating collet (described below) therein. Using fluid pressure in the downhole direction, the collet may actuate the sliding sleeve 106 from a closed position to an open downhole position to open one or more fluid ports 110 for subterranean formation fracturing (described below).

As shown in fig. 2, the tubular body 102 includes a tubular valve housing 112 releasably coupled to its uphole and downhole side top and

bottom subs

114 and 116, respectively, by threads 118 and locking screws 120, and having a sealing ring 122 for sealing its coupling. In these embodiments, the downhole end of the top sub 114 and the uphole end of the bottom sub 116 form uphole and

downhole stops

124 and 126, the

stops

124 and 126 for movably restraining the sliding sleeve 106 therebetween.

In these embodiments, top sub 114 includes a tapered inner surface 128 that tapers from its uphole end to its downhole end, such that the Inner Diameter (ID) of top sub 114 tapers from its uphole end to its downhole end to facilitate collet entry into spool valve 100 (described below).

The valve housing 112 includes one or more fluid ports 110 on its side wall near the wellhead end 132 for discharging high pressure fracturing fluid into the subterranean formation when the sliding sleeve 106 is displaced from the closed position to the open position under actuation pressure. The valve housing 112 also includes one or more pin holes 136 through which one or more shear pins 108 (see fig. 1) pass to lock the sliding sleeve 106 in a closed position to close the port 110. The valve housing 112 also includes one or more ratchet threads 138 on an inner surface thereof near the downhole end 136.

Figure 3 shows a cross-sectional view of the sliding sleeve 106 and the cannula body 152 with the bore 151. The sliding sleeve 106 has an Outer Diameter (OD) that is equal to or slightly less than the inner diameter of the valve housing 112 to allow the sliding sleeve 106 to move within the valve housing 112. In these embodiments, the sliding sleeve 106 includes a casing body 152, the casing body 152 receiving therein at least the coupling portion 153 of the protection sleeve 154 downhole thereof by threads 156 (see fig. 4) on an inner surface of the casing body 152 and corresponding threads 158 (see fig. 5) on an outer surface of the protection sleeve 154 to releasably couple to the protection sleeve 154.

As shown in fig. 4, the sleeve body 152 may include one or more circumferential sealing rings 168 (e.g., near the upper end 164 of the sleeve body 152) at appropriate locations on its outer surface to seal the interface between the valve housing 112 and the sliding sleeve 106 (see fig. 1), as desired.

The sleeve body 152 also includes one or more pin holes or recesses 170 at locations corresponding to the locations of the pin holes 136 of the valve housing 112 to receive the shear pins 108 when the sliding sleeve 106 is installed in the bore 104 of the valve housing 112 in the closed position, and the sleeve body 152 also includes one or more ratchet rings 172 around its downhole end 166 to engage the ratchet threads 138 on the interior surface of the valve housing 112 when the sliding sleeve 106 is in the open position.

On its inner surface, the casing body 152 is made of a suitable material (e.g., steel) and includes a downhole facing stop ring seat 180, the stop ring seat 180 being located on the uphole side of the threads 156 and accessible from the downhole end 166 of the casing body 152 to receive and support a high strength stop ring 192, and the casing body 152 further includes a contoured region 182 located on and adjacent to the uphole side of the stop ring seat 180 (correspondingly, other inner surface regions of the sliding sleeve 106 are represented as non-contoured regions).

The profile region 182 on the sleeve body 152 includes one (preferably two or more) circumferential grooves 184, such as

grooves

184A and 184B that form a unique locking profile (also referred to as a "sleeve profile"). Each groove 184 includes a well head wall that slopes radially inward from downhole at an obtuse angle relative to the longitudinal axis of the casing body 152. Each groove 184 also includes a right or acute downhole wall. That is, the downhole wall of each groove 184 is perpendicular to the longitudinal axis of the casing body 152, or is inclined radially inward from downhole to uphole and forms an acute angle with respect to the longitudinal axis of the casing body 152. With the grooves 184, the profile region 182 may receive a cartridge 200 having a matching outer surface profile 212 (referred to herein as a "matching cartridge") and allow a cartridge 200 having a non-matching outer surface profile (referred to herein as a "non-matching cartridge") to pass therethrough (described below).

Depending on the number of grooves 184, the inner diameter of the contoured region 182 on the sliding sleeve 106 can vary at different longitudinal locations thereof due to the grooves 184 in the sliding sleeve 106. However, the minimum inner diameter of the contoured region 182, including the stop ring 192, is generally the minimum inner diameter of the sliding sleeve 106. In other words, the minimum inner diameter of the sliding sleeve 106 occurs in the area of the contoured region 184 and the stop ring 192.

The outer diameter of the collet profile 212 on the collet 200 is greater than the minimum inner diameter of the profile region 182 on the sleeve body 152 to allow such a mating collet 200 collet profile 212 to initially minimally engage the profile region 182 on the sleeve body 152 when the collet is mated, but the outer diameter of the profile region 212 may significantly exceed the minimum inner diameter of the profile region 182 on the sleeve body 152 under fluid pressure applied to the collet 200 to allow the profile region 212 on the collet 200 to maximally engage the profile region 182 in a manner more fully described below.

It should be noted that the outer diameter of the collet 200 in the area of the ball seat 214 thereon is initially smaller than the inner diameter of the bore 151 and the contoured area 184 on the sleeve body 152. However, when a wellhead fluid pressure is applied against a ball 242 seated on the ball seat 214, the collet 200 may expand radially outward in the area of the ball seat 214 in a manner described more fully below, causing it to expand radially (i.e., the outer diameter of the collet 200 increases in the area of the ball seat 214), becoming very close to or equal to the inner diameter of the bore 151 in the casing body 152, providing benefits and advantages described more fully below.

The stop ring 192 is constructed of a material having a hardness greater than the hardness of the sliding sleeve material 106. For example, the stop ring 192 is made of a high strength material, such as tungsten carbide, cobalt chrome (e.g., stellite), nitrided steel, and/or other suitable high strength alloys, or combinations thereof, to provide enhanced pressure and wear resistance.

In some embodiments, at least a stop shoulder 194 of the stop ring 192 (described in more detail below) is hardened to a hardness greater than the hardness of the material of the sliding sleeve 106, or comprises a material having a hardness greater than the hardness of the sliding sleeve 106.

Fig. 6 shows a cross-sectional view of the high strength snap ring 192. The stop ring 192 has an outer diameter that is adapted to seat on the stop ring seat 180 of the cannula body 152 and a cross-sectional height "h" sufficient to extend radially inwardly to a position beyond the inner edge of the stop ring seat 180. In these embodiments, the uphole surface of the stop ring 192 slopes radially inward from downhole to uphole, forming a stop shoulder 194 on the uphole side edge that has an acute angle α relative to the longitudinal axis of the spool valve 100. As will be described in further detail below, the stop shoulder 194 of the stop ring 192 is adapted to abut a portion of the collet profile and engage a corresponding shoulder of the collet when the collet profile engages the sleeve profile 182 and prevents downhole movement of the collet member 200 relative to the sliding sleeve. Thus, the stop ring 192 may also be referred to as a "lock ring" for locking the collet downward.

As shown in fig. 7, the sliding sleeve 106 may be assembled by inserting the stop ring 192 into the cannula body 152 such that it seats on the stop ring seat 180. The protection sleeve 154 is then "screwed" onto the downhole end of the casing body 152 by engaging the threads 158 of the protection sleeve 154 with the threads 156 of the casing body 152. The wellhead end 160 of the protection sleeve 154 presses the stop ring 192 against the stop ring seat 180 to clamp the stop ring 192 firmly in place. The assembled sliding sleeve 106 is shown in figure 3.

The spool valve 100 may then be assembled by: the sliding sleeve 106 is inserted into the bore 104 of the valve housing 112 from either end of the valve spool 100 and into a closed position, the sliding sleeve 106 is locked in place by inserting shear pins or shear screws 108 through the pin holes 136 of the valve housing 112 and into the pin holes 170 of the valve housing 152, and then the valve housing 112 is coupled with the top sub 114 and the bottom sub 116. An assembled slide valve 100 is shown in fig. 1.

As shown in fig. 1, the longitudinal length of the sliding sleeve 106 is longer than the distance between the

stops

124 and 126 of the valve housing 112 so that when the sliding sleeve 106 is in the closed position, the protective sleeve 154 contacts the inner surface of the bottom sub 116 to isolate an annulus 196 located radially between the valve housing 112 and the sliding sleeve 106 and longitudinally between the downhole end 166 of the sliding sleeve 106 and the stop shoulder 126 from the bore 104 to prevent cement from entering the annulus 196 and interfering with valve operation.

As described above, the spool valve 100 includes a contoured inner surface area 182 having a unique locking profile that can receive and lock a mating cartridge and allow passage of a non-mating cartridge.

Fig. 8 is a cross-sectional view of a collet 200, which in these embodiments is in the form of a cylindrical cage having a longitudinal bore 202. The collet 200 typically has an outer diameter that is slightly smaller than the smallest inner diameter of the sliding sleeve 106 (except for the protrusions 222 described below) and includes one or more circumferential sealing rings 204 disposed on its outer surface as needed at the necessary locations to seal the interface between the collet 200 and the sliding sleeve 106 when the collet 200 is locked in the sliding sleeve 106.

As shown, the collet 200 includes a cylindrical uphole portion 206, a cylindrical downhole portion 208, and an intermediate portion 210, the intermediate portion 210 including a profile region 212 having a unique locking profile.

In these embodiments, the wellhead portion 206 includes a ball seat 214 on its inner surface for receiving a ball dropped from the wellhead. Wellhead portion 206 also includes a seal ring 216 on its inner surface for sealing the interface between the ball and wellhead portion 206 of the collet 200.

Middle portion 210 includes a plurality of circumferentially distributed longitudinal splines 218 coupled to uphole and

downhole portions

206 and 208. In these embodiments, the collet 200 is formed from a metal tube by cutting, stamping, or otherwise forming a plurality of longitudinal slots 220 in the intermediate portion 210 to form the splines 218.

One, more or all of the longitudinal splines 218 are made of a resilient soft material having sufficient elasticity and are shaped to include one or more protrusions 222 (e.g.,

protrusions

222A and 222B), respectively, in the profile region 212 extending radially outward from its outer surface, thereby forming a radially flexible locking profile (also referred to as a "collet profile"). The location and size of the protrusions 216 are selected so that the maximum outer diameter of the collet 200 is greater than the minimum inner diameter of the sliding sleeve 106 and its collet profile matches the sleeve profile of the matching sliding sleeve 106. Thus, when the cartridge 200 enters a spool valve 100 having a mating sliding sleeve 106 (e.g., the spool valve 100 is also referred to as a "mating spool valve 100"), the cartridge 200 may be locked in the mating sliding sleeve 106. Projection 222B, in its deepest downhole position, includes a shoulder 236 on its downhole side that is angled at the same acute angle a relative to the longitudinal axis of spool valve 100 as the angle of stop shoulder 194.

Figures 9-12 illustrate one example of actuating the collet 200 from its uphole position into the mating spool valve 100. As shown in fig. 9, the tapered inner surface 128 of the top sub 114 guides the collet 200 into the bore 104 as the collet 200 enters the spool valve 100.

As shown in fig. 10, when the profile area of the collet 200 enters the bore 104 and the maximum outer diameter of the collet 200 is greater than the minimum inner diameter of the sliding sleeve 106, the shaped splines 218 are biased inward and the collet 200 continues to move downhole.

As shown in fig. 11, when the contoured region 212 of the collet 200 fully overlaps the mating contoured region 182 of the sliding sleeve 106, the shaped splines 218 are not biased due to their resiliency. Thus, the collet 200 is received down into the sliding sleeve 106. As shown in fig. 12A and 12B, the collet 200 can be moved further downhole until the shoulder 236 of the projection 222B, which is at the lowest downhole position, engages the stop shoulder 194 of the high-strength stop ring 192.

Figure 12B shows an enlarged view of the sliding sleeve 106 and the

contoured regions

182 and 212 of the collet 200. As shown, the profile of each

profile region

182, 212 includes alternating grooves and ridges (or protrusions). In the example shown in fig. 12B, the profile of the profile region 182 includes two

grooves

184A and 184B, and a ridge 232 therebetween. The profile of the profile region 212 includes two ridges/

protrusions

222A and 222B and a groove 234 therebetween. To ensure that the

profile regions

182 and 212 match each other, the width of the groove on one of the two

profile regions

182 and 212 needs to be equal to or greater than the width of the corresponding ridge on the other of the two

profile regions

182 and 212 to receive the corresponding ridge therein. In the example shown in fig. 12B, the width of the groove (e.g., groove 184A, 184B, or 234) is sufficiently greater than the width of the corresponding ridge (e.g.,

ridge

222A, 232, or 222B) so that after the collet 200 is locked down in the sliding sleeve 106, the collet 200 can be moved further downhole until the protrusion 222B located at the deepest downhole position engages the high strength stop ring 192.

As shown in fig. 12B, a high strength stop ring 192 is used to engage the protrusion/ridge 222B at the deepest downhole location under high pressure to enhance the downhole lock between the sliding sleeve 106 and the collet 200. In addition, the stop ring 192 is shaped with a wellhead stop shoulder 194 at an acute angle relative to the longitudinal axis of the spool valve 100, and the downhole side of the projection 222B at the deepest downhole position also forms a shoulder 236 with a matching acute angle, so that engagement of the

shoulders

194 and 236 increases the strength against downhole pressures applied to the collet 200. In these embodiments, when the

shoulders

194 and 236 engage each other, the collet 200 and other corresponding ridges (e.g., ridges 222A and 232) of the sliding sleeve 106 engage to further increase the strength against downhole pressures applied to the collet 200.

As shown in fig. 13, after the collet 200 is locked in the sliding sleeve 106, the ball 242 may fall off the surface and into the spool valve 100. The ball 242 is made of a rigid material (e.g., ceramic or metal) and is sized to seat on the ball seat 214 of the collet 200.

After the ball 242 engages the ball seat 214 and sealingly blocks the bore 202 of the collet 200, fluid pressure is applied uphole to the ball 214 and the collet 200. When the collet 200 is locked down onto the sliding sleeve 106, the sliding sleeve 106 is then actuated, shearing the shear pins 108 and moving down to the open position to open the fluid ports 110. As shown in fig. 14, ratchet ring 172 on sliding sleeve 106 engages ratchet threads 138 on valve housing 112 to prevent movement of sliding sleeve 106 uphole. High pressure fracturing fluid may then be pumped downhole and ejected out of fluid ports 110 to fracture the formation.

The fracturing fluid typically has a high pressure and any failure in the spool valve 100 may cause the fracturing process to fail. For example, if the engagement between the collet 200 and the sliding sleeve 106 fails, the high pressure fracturing fluid may actuate the collet 200 further downhole, causing the fracturing process to fail.

It will be appreciated by those skilled in the art that the spool valve 100 of the above embodiment includes a high strength snap ring 192, the high strength snap ring 192 serving to strengthen the engagement between the collet 200 and the sliding sleeve 106, thereby significantly reducing the risk of failure.

In some embodiments, the outer diameter of the collet 200 at its

projections

222A and 222B is less than the inner diameter of the sliding sleeve 106 at its

recesses

184A and 184B. As shown in fig. 15A and 15B, in these embodiments, after the high pressure fracturing fluid is pumped downhole and actuates the sliding sleeve 106 to the open position, the high pressure fracturing fluid further actuates the collet 200 slightly downhole such that the splines are forced 218 to expand radially outward such that the

protrusions

222A and 222B of the collet 200 further engage the

recesses

184A and 184B of the sliding sleeve 106, thereby enhancing pressure resistance.

In some embodiments, a downhole fracturing system including a plurality of slide valves 100 may be used to fracture a subterranean formation. FIG. 16 shows one example of fracturing a subterranean formation using spool valve 100. In this example, a horizontal well is drilled in the subterranean formation 274, the horizontal well including a horizontal wellbore section 272. A casing string 276 including a plurality of spool valves 100 is then run into the wellbore section 272. Each sliding sleeve 100 includes a unique casing profile. The spool valve 100 may be separated by other joints as desired.

After the casing string 276 is in place, cementing may be performed by pumping cement fluid down into the casing string 276. As described above and shown in fig. 1, in each slide valve 100, a protective sleeve 154 prevents cement from entering annulus 196 and interfering with the operation of the valve. After cementing, a cleaning fluid may be pumped downhole to clean the joint, including the spool valve 100. The wiper arm may also be used for cleaning as desired.

In this example, the formation 274 surrounding the wellbore section 278 will be fractured and the spools 100B and 100C will need to be opened. Thus, a first collet (not shown) that mates with spool valve 100C is pumped downhole through casing string 276. Because the first collet is not matched to the

spool valves

100A and 100B (i.e., the collet profile of the first collet is not matched and cannot be received in the sleeve profile of the

spool valves

100A and 100B), the first collet passes through the

slide sleeves

100A and 100B and is locked in the spool valve 100C.

To open the fluid port of the spool valve 100C, the ball is dropped and engages the ball seat of the first collet and blocks the bore of the first collet. Fluid pressure is then applied to actuate the engaged ball, first collet, and sliding sleeve to shear the shear pins of the sliding valve 100C and move the sliding sleeve downhole to an open position to open the fluid portion of the sliding sleeve 100C.

After the spool valve 100C opens, a second collet, mated with the spool valve 100B, is pumped downhole to lock onto the spool valve 100B. The ball is then dropped into engagement with the second collet and fluid pressure is applied to open the spool valve 100B.

After opening all of the spools 100B and 100C in the wellbore section 278, the balls in these spools are removed by drilling, dissolving, retrieving to the surface, etc., except for the ball in the spool at the lowest position downhole. In the example shown in fig. 16, the ball in spool valve 100C is held in place, while the ball in spool valve 100B is removed. High pressure fracturing fluid is then pumped into the casing string 276 and ejected out of the fluid ports of the spool valves 100B and 100C to fracture the formation 274.

In the above examples, wellbore isolation devices (e.g., packers) may be used to isolate wellbore sections to be fractured, as is known in the art, and thus omitted herein.

As can be seen from the above examples, the fracturing process may use multiple sliding sleeves 100 having apertures 104 of approximately the same size, thereby ensuring consistent fluid flow. The collet 200 and ball 242 may also be the same size, thereby simplifying flow and reducing completion costs.

In the above-described embodiment shown in fig. 3-7, the protection sleeve 154 is releasably coupled to the sleeve body 152 by engaging

threads

158 and 156. In some alternative embodiments, the protection sleeve 154 may be coupled to the sleeve body 152 by other suitable means. For example, in one embodiment, the protection sleeve 154 may be permanently coupled to the sleeve body 152 by welding.

In the above embodiment, the collet 200 is in the form of a cylindrical cage having a plurality of splines mounted on a cylindrical wellhead portion 206 and a cylindrical downhole portion 208, thereby eliminating the need for external means (e.g., springs) to radially actuate or deform the collet 200 to engage and lock in the sliding sleeve. In another particular embodiment, the flexible splines are mounted at their longitudinally opposite ends to the uphole and

downhole portions

206 and 208 and the collet is further configured such that the splines are located in the internal profile 184 within the sliding sleeve 106 upon initial engagement, advantageously causing the splines to further radially flex on the collet 200 upon application of uphole fluid pressure to a ball located in the ball seat 214 of the collet 200, thereby causing the splines with the collet profile 212 to further and more widely engage within the sliding sleeve 184, thereby reducing the risk that the collet 200 will not engage a selected casing, or reducing the risk that the mating profile on the collet 200 may disengage from the mating profile 184 on the sliding sleeve 106 upon application of uphole fracturing pressure, which in the event of a failure, prevents injection of fracturing fluid into the well at high pressure at the open port 110.

In some alternative embodiments, a downhole fracturing system comprising a tubular string with one or more slide valves 100 may be used to fracture a wellbore section. The wellbore may be a cased wellbore or a non-cased wellbore.

While the spool valve 100 is used to fracture a horizontal wellbore section in the example shown in fig. 16, those skilled in the art will appreciate that in some alternative embodiments, the spool valve 100 may be used to fracture a vertical wellbore section.

In the above embodiments, the collet 200 may include one or more sealing rings 204 on an outer surface thereof for sealing an interface between the collet 200 and the sliding sleeve 106 as the collet 200 enters the sliding valve 100. However, such seal rings 204 may wear and fail, typically during pumping of the cartridge downhole, as the cartridge 200 moves within the sliding sleeve 106, thereby causing the sliding valve 100 to fail. Moreover, when pumping the collet through a mismatched sliding sleeve, a significant fluid pressure is typically required to overcome the friction caused by the movement of the sealing ring 204 along the inner surface of the sliding sleeve 106.

In some alternative embodiments, the collet 200 need not include any sealing ring 204 on its outer surface. In these embodiments, the spool valve 100 is the same as that shown in fig. 1, and the outer diameter of the non-contoured region of the collet 200 is slightly less than the minimum inner diameter of the sliding sleeve 106, thereby avoiding friction caused by the sealing ring 204, thus allowing the collet 200 to pass through an unmatched spool valve 100 at a lower fluid pressure.

In these embodiments, the sliding sleeve is made of a suitable metal (e.g., steel). As shown in fig. 17A and 17B, the uphole portion 206 of the collet 200 is configured with a radially outwardly expandable metal portion 206', and the ball seat 214 includes a ball seat surface 282 that slopes radially inward from uphole to downhole at an acute angle relative to the longitudinal axis 284 of the collet 200.

After the collet 200 is locked in the spool valve 100, a suitably sized ball 242 is pushed against the ball seat 214 under downhole fluid pressure. When fluid downhole pressure is applied to the uphole side of the ball 242, the ball 242 will press against the inclined surface 282 of the ball seat 214, thereby converting the downhole fluid pressure to a radially outward pressure and radially expanding the expandable metallic portion 206 'of the collet 200 to substantially reduce the gap between the collet 200 and the sliding sleeve 106, or even force the outer surface of the expandable metallic portion 206' into tight engagement with the inner surface of the sliding sleeve 106, thereby forming a metal-to-metal seal at the interface between the collet 200 and the sliding sleeve 106.

As shown in fig. 17B, a surface 282 of ball seat 214 is inclined at an inclination angle θ relative to longitudinal reference direction 284. In some embodiments, the tilt angle θ is about 55 °. For a metal collet having an American Petroleum Institute (API) N80 grade steel modulus of elasticity, the ball seat 214 on the collet 200 has a nominal diameter of 4.555 inches, the collet has a nominal thickness of 0.23 inches, and the pressure on a ball 242 having a nominal diameter of 4.250 inches is about 1500psi, and the gap between the collet 200 and the inner diameter of the sliding sleeve 106 is initially in the range of 0.004 to 0.014 inches prior to radial expansion (see example a and fig. 18 below), for which a tilt angle of about 55 ° is a satisfactory angle at which the necessary radially outward force can be transmitted to the collet 200 to cause the collet 200 to expand sufficiently radially to form an adequate metal-to-metal seal with the sliding sleeve 106.

In other embodiments where the collet 200 may be made of a stronger or less resilient material (i.e., having a higher modulus of elasticity), and/or have a greater thickness, and/or the initial clearance between the collet diameter 200 and the sliding sleeve diameter 106 is greater than 0.004 to 0.014 inches, and/or the pressure on the ball 242 is less than 1500psi, it may be desirable to reduce the angle of inclination θ to about 35 ° to enable the ball seat 214 to transmit sufficient radially outward force to sufficiently radially increase the collet diameter 200 to achieve the desired metal-to-metal seal with the bore.

In some alternative embodiments, the tilt angle θ is about 50 ° to about 60 °. In some alternative embodiments, the tilt angle θ is about 40 ° to about 70 °. In some alternative embodiments, the tilt angle θ is about 30 ° to about 80 °.

Thus, where the collet 200 is configured to allow for radial enlargement, this can advantageously allow the overall outer diameter of the collet 200 to be reduced. This reduction in diameter in the area of the ball seat 214 and in the profile area 212 of the collet allows for easier passage of the collet 200 and profile area 212 with less interference with the profile area 184 of the respective wellhead slide sleeve 106 that is not intended to be actuated, thereby reducing frictional wear on such profile area 212 of the collet 200, but still maintaining the ability of the collet 200 to eventually form a seal in the area of the ball seat 214 upon arrival and further engage the collet profile area 212 thereon with the predetermined downhole casing 106 and the corresponding desired mating profile 184 thereon.

Specifically, it is important that, with this radial expansion capability of the collet 200, wear of the collet profile 212 thereon is reduced, thereby maintaining the integrity of the collet profile 212 and ensuring that when the collet 200 reaches the sliding sleeve 106 that requires actuation, the corresponding profile 212 thereon can be sufficiently and reliably engaged while forming an initial metal-to-metal seal to allow pressure to build up on the uphole side of the ball 242. The pressure on the wellhead side of the ball 242 increases as the collet 200 lockingly engages the sliding sleeve 106, in turn causing a "domino" effect whereby the buildup of such pressure causes a (further) radial expansion of the collet 200, which in turn causes an increase in the intermetallic seal, which causes a further buildup of pressure which in turn causes an increase in the radial expansion, which in turn causes an increase in the intermetallic seal. Wellhead pressure will build up in this manner to the point where the shear pins 108 hold the sliding sleeve 106 in place for shearing, and then allow the sliding sleeve 106 to move downhole in the valve 100 to open the port 110.

Figure 18 shows one example of a collet 200 of the present invention slidably received in the sliding sleeve 106, the collet 200 being that of the preferred embodiment described above. Specifically, in such preferred embodiments, the thickness, material, and initial radial clearance of the collet 200 in the region of the ball seat 214 from the bore 151 of the casing body 152 is such that when the ball 242 is seated in the ball seat 214 and fluid pressure of at least 150psi is applied thereto, the amount of radially outward expansion of its outer diameter is greater than 0.09% to provide a sufficient metal-to-metal seal between the outer diameter of the collet 200 in the region of the ball seat 214 and the bore 151 of the casing body 152. Specifically, the outer diameter of the collet 200 in the area of the ball seat 214 is capable of expanding radially outward upon application of fluid pressure to the ball 242 seated therein, preferably by at least 0.09%, and preferably by at least 0.2%, and more preferably by at least 0.3%, upon application of a wellhead fluid pressure of at least 150psi, to improve the initial clearance of the profile region 212 on the collet 200 having a mismatched profile, but upon engagement with the desired profile region 184 on the selected sliding sleeve 106, such that it forms a sufficient seal with the collet 200 in the area of the ball seat 214 to create a "domino" effect and to allow further radial expansion of the collet 200 to strengthen the metal-to-metal seal, whereby the radial outward expansion and metal-to-metal seal are sufficient to allow sufficient pressure to be applied to shear the shear pin 108.

In the above embodiment, the collet 200 is formed from a metal tube by cutting, stamping, or otherwise forming a plurality of longitudinal slots 220 in the intermediate portion 210 to form the splines 218. In some alternative embodiments, splines 218 may be coupled to uphole portion 206 and downhole portion 208 by other suitable means (e.g., welding, screwing, etc.).

Example 'A'

As mentioned above, fig. 18 illustrates one example of a collet 200 of the present invention, the collet 200 being slidably received in the sliding sleeve 106. The collet 200 is configured with a radially expandable portion 206 "in the area of the ball seat 214.

Specifically, in this example, the collet 200 is formed of API NP 80 grade steel in the region of the ball seat 214, with an elastic modulus of 29,000,000 and a poisson's ratio of 0.29. Sliding sleeve 106 is also formed from API N80 grade steel.

In this selected example, the initial radial clearance of the collet 200 at the interface between the radially outer periphery of the collet 200 and the inner bore 151 of the sleeve body 152 in the region of the ball seat 214 is 0.002 to 0.007 inches, which is determined by applying the material tolerances of the collet 200 (i.e., the difference between the maximum and minimum dimensional tolerances between the outer diameter of the collet 200 and the inner diameter of the inner bore 151 of the sliding sleeve 106 [ i.e., (4.567-4.553)/2 and (4.562-4.558)/2 ].

The chuck 200 has a nominal thickness in the region of the ball seat 214 (i.e., on the uphole side of the ball seat 214) of 0.149 to 0.1515 inches [ i.e., (4.553-4.255)/2 to (4.558-4.255)/2], a nominal thickness on the downhole side of the ball seat 214 of 0.2305 to 0.233 inches [ i.e., (4.553-4.092/2 to (4.558-4.092)/2],

the ball seat 214 of the chuck 200 is inclined at an angle theta of 55 deg.. The nominal diameter of the ball 242 is 4.250 inches.

After the ball 242 is seated in the ball seat 214, the aforementioned 0.002-0.007 inch initial radial clearance is sufficient to initially partially prevent fluid flow through the interface when 1500psi fluid pressure is applied uphole to the ball 242. As the injection of fluid continues under pressure, fluid pressure builds up correspondingly on the uphole side of the ball 242 due to this partial initial blockage. Due to the inclination angle θ of the ball seat 214, the radially expandable portion 206' of the collet 200 generates a radially outward force applied to the tubular collet 200 in the area of the ball seat 214 in response to the force applied to the ball 242 by the applied fluid pressure. This applied radially outward force causes the metal portion 206' to expand radially outward, thereby eventually eliminating or significantly reducing the 0.002 to 0.007 inch radial gap described above and forming an intermetallic seal at the interface between the collet 200 and the sliding sleeve 106.

Specifically, where the outer diameter of the radially outwardly expandable metal portion 206' is a maximum of 4.558 inches and the inner diameter of the bore of the sleeve is a minimum of 4.558 inches (i.e., 4.562-4.558/4.558), the radially-outward-expandable metallic portion 206' has a radial expansion of at least 0.09%, in the case where the outer diameter of the radially outwardly expandable metal portion 206' is a nominal value of 4.555 inches and the bore diameter of the sliding sleeve is a nominal value of 4.565 inches (i.e., 4.565-4.555/4.555), with a nominal radial expansion of 0.02%, in the case where the radially outwardly expandable metal portion 206' has an outer diameter of a minimum of 4.553 inches and the sleeve has an inner diameter of an opening of a maximum of 4.567 inches (i.e., 4.567-4.553/4.553), the amount of radial expansion is at least 0.03%, and therefore in all cases results in a reduced radial clearance, thereby forming an intermetallic seal between the collet 200 and the sliding sleeve 106.

It will be apparent to those skilled in the art that certain of the above parameters may be varied to achieve the desired result of enabling the radially expandable collet to advantageously reduce contact with the wellhead sliding sleeve upon reaching the desired sliding sleeve 106 through the wellhead sliding sleeve, thereby maintaining the dimensional tolerances of the collet 200 (particularly the outside diameter in its contoured region 212 and in the region of the ball seat 214) and being more easily flowed downhole due to the reduction in diameter, but can be "increased" upon locking engagement with the desired selected casing and application of fluid pressure to maintain an effective seal and allow for the build up of pressure sufficient to shear the shear screw 108.

In this example, the sliding sleeve 106 and the collet 200 are constructed of API N80 grade steel. Those skilled in the art will appreciate that in various alternative embodiments, the sliding sleeve 106 and collet 200 may be made of other suitable materials (e.g., API P110 grade steel) having similar modulus of elasticity, thereby achieving a similar radial increase when 1500psi pressure is applied.

However, to reduce the magnitude of the pumping pressure while achieving a similar radial increase (i.e., 0.02% nominal radial increase), the collet 200 may also be constructed of a material having a modulus of elasticity on the order of less than that of API NP 80 grade steel (i.e., 1/10 for the modulus of elasticity of API NP 80 grade steel). This results in the applied pressure also only needing 1/10 (i.e., 150psi) of the applied pressure described above, while still achieving the desired nominal radial increase of 0.02%.

Similarly, as shown in FIG. 18, by decreasing or increasing the angle of inclination θ of the ball seat 214 of the collet 200, the effective radially outward force exerted by the ball 242 on the outer circumference of the collet 200 in the area of the ball seat 214 can be effectively varied, thereby increasing or decreasing, respectively, the magnitude of the radial force exerted on the collet 200.

Thus, for example, at a constant fluid pressure of 1500psi, reducing the tilt angle θ from 55 to 30 increases the applied force, while reducing the required fluid pressure from 1500psi or using a material with a proportionally reduced modulus of elasticity (i.e., using a less stiff material with a greater amount of radial deformation per applied unit force) can achieve a similar increase in radial expansion (nominally 0.02%).

Other permutations and combinations of the above variables for achieving the above radial increase will now be further demonstrated to those skilled in the art.

For example, if the tilt angle θ is increased from 55 ° to 80 ° to reduce the effective radially outward force normally applied to the chuck 200, then to achieve a similar amount of radial expansion of the chuck 200 (nominally 0.02%), one or more of the following actions may be taken:

(i) modifying the material of the collet 200 to a material having a lower modulus of elasticity (i.e., less stiffness);

(ii) increasing the 1500psi fluid pressure exerted on the ball 242 to achieve the same tangential force as previously applied using the 55 deg. tilt angle theta; or

(iii) Reducing the thickness of the collet 200 in the area of the ball seat 214 (assuming the applied pressure and resulting radial force do not exceed the yield stress of the collet 200 in the area of the ball seat 214);

further description of the invention

Figure 19 shows a collet 200 in some alternative embodiments. In these embodiments, the spool valve 100 is the same as the spool valve shown in FIG. 1.

As shown in fig. 19, in these embodiments, the collet 200 includes a closed wellhead end 284. The rest of the cartridge 200 is the same as that shown in fig. 8.

In these embodiments, the spool valve 100 does not require the ball 242 to actuate. Instead, to actuate the spool valve 100, the mating cartridge 200 is pumped downhole and locked into the spool valve 100. Fluid pressure is applied to the closed uphole end 284 of the collet 200 and thereby shears the shear pin 108 and actuates the sliding sleeve 106 of the spool valve 100 to move downhole to the open position. As described above, the high strength snap ring 192 provides enhanced pressure and wear resistance.

In the above embodiment, the sliding sleeve 106 includes a high strength stop ring 192 at the downhole end of its contoured region 182 forming a stop shoulder 194 for locking the mating cartridge 200. In some alternative embodiments, the stop ring 192 is made of the same material as the sliding sleeve 106, but is preferably made of a higher strength and/or hardened material and/or nitrided material, such as, but not limited to, tungsten carbide. In some embodiments, at least the stop shoulder 194 of the stop ring 192 is hardened to or includes a hardness that is substantially or approximately equal to the hardness of the downhole portion of the collet profile that matches the collet 200.

In some alternative embodiments, the sliding sleeve 106 does not include any stop ring 192. Instead, the uphole end of the protection sleeve 154 forms a stop shoulder 194 for locking the mating collet.

In other alternative embodiments, the sleeve body 152 and the protection sleeve 154 are integral to form the sliding sleeve 106 and include a radially inwardly extending circumferential ridge that forms the stop shoulder 194. Thus, in these embodiments, the sliding sleeve 106 does not include any stop ring 192.

In some alternative embodiments, the sliding sleeve 106 includes only the sleeve body 152 and does not include any protective sleeve 154. In these embodiments, the stop ring 192 is welded, mounted, or otherwise integrated into the cannula body 152.

In some embodiments, multiple casing profiles and collet profiles may be obtained and used on the same tubular string in a downhole fracturing system.

For example, figures 20A-20D illustrate four sleeve profiles 182-1-182-4 (generally indicated at 182) on the inner surface of the sliding sleeves 106-1-106-4 and collet profiles 212-1-212-4 (generally indicated at 212) on the outer surface of the collets 200-1-200-4, respectively, corresponding to the sleeve profiles.

As shown, each of the casing profiles 106-1 to 106-4 includes at least two

grooves

184A and 184B (hereinafter also referred to as "casing grooves") and one ridge 232 (hereinafter also referred to as "casing ridge") located longitudinally between the two

grooves

184A and 184B.

Accordingly, each collet profile 200-1 to 200-4 includes at least two

ridges

222A and 222B (hereinafter also referred to as "collet ridges") and a groove 234 (hereinafter also referred to as "collet grooves") located between the two

ridges

222A and 222B. Further, the length of each

groove

184A, 184B, 234 is greater than or equal to the length of each

ridge

222A, 222B, 232 such that the collet profiles 200-1 to 200-4 may be received in the respective sleeve profiles 106-1 to 106-4.

By changing the

groove

184A and 184B, and the length of the ridge 232, a plurality of unique individual sleeve profiles (and corresponding unique individual collet sleeves) may be obtained. In these embodiments, the difference in length between the two casing profiles (e.g., the difference in length of casing profiles 182-2 and 182-3) is a predetermined design parameter L_bIs an integer multiple of (L)_b>0. In addition, the difference in length between the respective corresponding grooves or ridges of the two casing profiles (e.g., the difference in length of groove 184A of casing profiles 182-1 and 1822, or the difference in length of groove 184B of casing profiles 182-1 and 182-2) is also a predetermined design parameter L_bIs an integer multiple of (L)_b>0。

Referring to fig. 21A, the following parameters (both greater than zero) are used for the casing profile 182:

L_sthe longitudinal length of the sleeve profile 182;

S_g1the longitudinal length of the slot 184A of the sleeve profile 182;

S_rthe longitudinal length of the ridge 232 of the sleeve profile 182; and

S_g2the longitudinal length of the slot 184B of the sleeve profile 182.

Parameter L_s、S_g1、S_rAnd S_g2Measured at the radially innermost point of the casing profile 182.

The following parameters (all greater than zero) are used for the collet profile 182:

L_cthe longitudinal length of the collet profile 212;

C_r1the longitudinal length of the ridge 222A of the collet profile 212;

C_gthe longitudinal length of the slots 234 of the collet profile 212; and

C_r2the longitudinal length of the ridges 222B of the collet profile 212.

Parameter L_c、C_r1、C_gAnd C_r2Also measured at the radially innermost point of the collet profile 212.

As described above, in a matched pair of collet and sleeve profiles, the length of the slot (including

sleeve slots

184A and 184B and length S of collet slot 234)_g1、S_g2And C_g) Must be greater than or equal to phaseThe length of the corresponding ridge (including the

collet ridges

222A and 222B and the length C of the cannula ridge 232)_r1、C_r2And S_r) I.e. S_g1≥C_r1、S_g2≥C_r2And C_g≥S_rSuch that the collet profile 212 is receivable in the mating sleeve profile 182.

In these embodiments, the uphole surfaces of

casing slots

184A and 184B and stop ring 192 are sloped such that they extend radially inward toward the wellhead. The uphole surfaces of the

collet ridges

222A and 222B and the downhole surface of the collet ridge 222B are sloped such that they extend radially outward downhole. These slopes affect the manner in which the sleeve ridge 232 and the

collet ridges

222A and 222B are received in the collet slots 234 and the

sleeve slots

184A and 184B.

For ease of illustration, in these embodiments, the uphole side surfaces of

casing grooves

184A, 184B, stop ring 192 and

collet ridges

222A, 222B and the chamfer of downhole side surfaces of collet ridges 222B are substantially the same.

As shown in fig. 21B and 21C, due to the chamfer, after the collet profile 212 fits onto the mating casing profile 182, the collet 200 can expand radially outward and move further downhole a short distance₁(this distance is a design parameter predetermined by the chamfer and degree of engagement described above), is received into the casing profile 182 until the downhole side surface of the collet ridge 222B engages the stop shoulder 194 of the stop ring 192.

Referring again to FIG. 21A, on the cannula profile 182, the length S of the ridge 232_rIs defined as:

S_r＝L_a+nL_b, (1)

wherein 1 ≧ 0 is a predetermined design parameter, L_aIs a predetermined design parameter and L_a>0, n is an integer of 0 or more, L_bIs a predetermined design parameter and L_b>0. Thus, when n is 0, the ridge 232 has a minimum length S_r＝L_a。

The length S of the

slots

184A and 184B_g1And S_g1Is defined as:

S_g1＝m₁L_b+(1-)L_a, (2)

S_g2＝m₂L_b, (3)

wherein m is₁Is an integer and m₁≥1，m₂Is an integer and m₂>1. In addition to this, the present invention is,

m₁+m₂＝K, (4)

wherein K>2 is a positive integer, increasing m for a casing profile having the same K₁Will reduce m₂Effectively changing the location of the ridge 232 on the cannula profile.

The length L of the sleeve profile 182_sThe method comprises the following steps:

L_s＝S_r+S_g1+S_g2＝L_a+(n+K)L_b. (5)

due to L_aAnd L_bIs a predetermined design parameter, so that different lengths L can be obtained by selecting different n and K_sA plurality of cannula profiles 182.

On the collet profile 212, the

ridges

222A and 222B and the length C of the collet groove 234_r1、C_r2、C_gIs defined as:

C_r1＝S_g1-t₁L_b-₂＝(m₁-t₁)L_b+(1-)L_a-₂, (6)

C_r2＝S_g2-t₂L_b＝(m₂-t₂)L_b, (7)

C_g＝S_r+S_g2-C_r2+₂＝S_r+t₂L_b+₂＝L_a+(n+t₂)L_b+₂. (8)

wherein, t₁、t₂And₂is a predetermined design parameter, and 1 ≧ t₁≥0、1≥t₂Is not less than 0 and₂≥0。

length L of collet profile 212_cThe method comprises the following steps:

L_c＝C_r1+C_r2+C_g＝L_s-t₂L_b＝L_a+(n+K-t₂)L_b. (9)

parameter(s)₂It is only determined whether the downhole side surface of the collet ridge 222A will engage the downhole side surface of the casing groove 184A. In some embodiments of the present invention, the,₂0 so that when the collet 200 engages the casing 106 under pressure applied from the wellhead, the downhole side surfaces of the collet ridges 222A engage the downhole side surfaces of the casing groove 184A and the downhole side surfaces of the collet ridges 222B engage the stop shoulder 194, thereby providing enhanced pressure resistance. In some other embodiments of the present invention, the,₂>0, which, among other conditions (described later), allows the flex splines 218 to further expand and flex radially outward under fluid pressure to enhance engagement between the collet 200 and the sliding sleeve 106.

Referring again to FIG. 21A, in₂In the embodiment of 0, when t₁When 1, sleeve groove 184A and collet ridge 222A have a maximum length difference L_b(ii) a When t is₁At 0, sleeve groove 184A and collet ridge 222A have the same length. Similarly, when t is₂ Sleeve slot 184B and collet ridge 222B have a maximum length difference L when 1_b(ii) a When t is₂At 0, sleeve groove 184B and collet ridge 222B have the same length.

At this point, the parameters of the casing profile 182 become: in some embodiments, the design parameter is predetermined to be L_a＝L_b，t₁＝t₂T, and 1 ≧ t ≧ 0. At this point, the parameters of the casing profile 182 become:

S_r＝(n+)L_b, (10)

S_g1＝(m₁+1-)L_b, (11)

S_g2＝m₂L_b, (12)

m₁+m₂＝K, (13)

L_s＝(n+K+1)L_b. (14)

the parameters of the collet profile 212 become:

C_r1＝S_g1-tL_b-₂, (15)

C_r2＝S_g2-tL_b, (16)

C_g＝(n+t+)L_b+₂, (17)

L_c＝(n+K+1-t)L_b. (18)

at a given point₂The parameter t determines the difference in length between a groove and its corresponding ridge. If t is 0, the sleeve profile 182 and the collet profile 212 have the same length. If t is 1, the sleeve contour 182 and the collet contour 212 have a maximum length difference L_b. In that₂In the embodiment of 0, if t is 0, the groove and its corresponding ridge have the same length. If t is 1, the difference in maximum length between the groove and the ridge corresponding thereto is L_b。

Various sleeve profiles and collet profiles are available. For ease of illustration, the cannula profiles and the collet profiles are organized into profile groups, and the profile groups are organized into profile categories. In the following, the casing profiles are indicated in the form of "S ({ class letter } { group number } - { profile number })", where "{ class letter }" may be A, B, C, … …, indicating the profile class to which the casing profile belongs, "{ group number }" may be 1, 2, 3, … …, indicating the profile group to which the casing profile belongs, and "{ profile number }" may be 1, 2, 3, … …, indicating the order of the casing profiles in the profile group. For example, the cannula profile "S (A1-1)" represents the first cannula profile in set A1.

Similarly, the casing profile is represented in the form of "C ({ class letter } { group number } - { profile number })". For example, collet profile "C (B2-3)" represents the third collet profile in group B2.

It can be seen that n, K and m can be varied₁To generate a plurality of sleeve profiles 182 and collet profiles 212. Thus, for ease of illustration, the casing profile may also be represented as S [ n, K, m ]₁]The chuck profile can also be expressed as C [ n, K, m ]₁]。

In these embodiments, for a given L_bThe sum of (n + K) determines the length L of the casing profile_sAnd length L of the collet profile_c. In particular, the casing profiles in each profile class (e.g., "A") have the same length L_s＝(n+K+1)L_bAnd the collet profiles in the same profile class have the same length L_c＝(n+K+1-t)L_b。

The parameter n determines the length of the ferrule ridge 232 and the length of the collet groove 234. Thus, the sleeve profiles in each profile group (e.g., "A1") have the same ridge 232 length S_r＝(n+)L_bAnd the collet profiles in the same profile group have the same slot 234 length C_g＝(n+t+)L_b+₂。

Each profile set comprising (K-2) sleeve profiles and (K-2) corresponding collet profiles having the same n and the same K, wherein all of the (K-2) sleeve profiles have the same length L_s＝(n+K+1)L_bAnd the same S_r＝(n+)L_bAnd all (K-2) collet profiles have the same length L_c＝(n+K+1-t)L_bAnd the same C_g＝(n+t+)L_b+₂。

It will be appreciated by those skilled in the art that if t is equal to or close to 0, the collet profile fully or almost fully conforms to the casing profile, and thus there may be a risk that the collet profile cannot fit into a matching casing profile, for example due to large manufacturing tolerances of the collet profile and/or the casing profile and/or the collet 200 entering the sliding sleeve 106 at high speed such that the offset collet profile does not have sufficient time to return to an unbiased state before the collet 200 moves out of the sliding sleeve 106.

On the other hand, if t is equal to or close to 1, the grooves and their corresponding ridges have a maximum length difference L_bAnd there may be a risk that the collet profile may erroneously fit into a non-matching sleeve profile (explained later).

In some embodiments, t may be selected to be sufficiently greater than zero and sufficiently less than one to ensure that:

(i) a collet profile corresponding to a certain sleeve profile in a group is easily rejected by any other sleeve profile in the same group; and

(ii) the difference in length between a groove and its corresponding ridge (e.g., the difference in length between sleeve groove 184A and collet ridge 222A, the difference in length between collet groove 234 and sleeve ridge 232, or the difference in length between sleeve groove 184B and collet ridge 222B) is sufficient to ensure that the ridge is easily received into the groove.

For example, in one embodiment, t may be selected to be 0.9 ≧ t ≧ 0.1. In alternative embodiments, t may be selected to be 0.8 ≧ t ≧ 0.2. In alternative embodiments, t may be selected to be 0.7 ≧ t ≧ 0.3. In alternative embodiments, t may be selected to be 0.6 ≧ t ≧ 0.4. In some alternative embodiments, t may be selected to be about 0.5.

Fig. 22 shows a group a1 of four sleeve profiles and four corresponding collet profiles when n is 0 and K is 6, the sleeve profiles having the same length L_s＝7L_b。

Fig. 23 shows a group B1 of six sleeve profiles and six corresponding collet profiles when n is 0 and K is 8, the sleeve profiles having the same length L_s＝9L_b。

Fig. 24 shows a group C1 of eight sleeve profiles and eight corresponding collet profiles when n is 0 and K is 10, the sleeve profiles having the same length L_s＝11L_b。

Fig. 25 shows a group D1 of ten sleeve profiles and ten corresponding collet profiles when n is 0 and K is 12, the sleeve profiles having the same length L_s＝13L_b。

Fig. 26 shows a group a2 of three sleeve profiles and three corresponding collet profiles when n is 1 and K is 5, the sleeve profiles having the same length L_s＝7L_b。

Fig. 27 shows a group B2 of five sleeve profiles and five corresponding collet profiles when n is 1 and K is 7, the sleeve profiles having the same length L_s＝9L_b。

Fig. 28 shows a set C2 of seven sleeve profiles and seven corresponding collet profiles when n is 1 and K is 9, the sleeve profiles having the same length L_s＝11L_b。

Fig. 29 shows a set D2 of nine sleeve profiles and nine corresponding collet profiles when n is 1 and K is 11, the sleeve profiles having the same length L_s＝13L_b。

Fig. 30 shows a group a3 of two sleeve profiles and two corresponding collet profiles when n is 2 and K is 4, the sleeve profiles having the same length L_s＝7L_b。

Fig. 31 shows a group B3 of four sleeve profiles and four corresponding collet profiles when n is 2 and K is 6, the sleeve profiles having the same length L_s＝9L_b。

Fig. 32 shows a group C3 of six sleeve profiles and six corresponding collet profiles when n is 2 and K is 8, the sleeve profiles having the same length L_s＝11L_b。

Fig. 33 shows a group D3 of eight sleeve profiles and eight corresponding collet profiles when n is 2 and K is 10, the sleeve profiles having the same length L_s＝13L_b。

Fig. 34 shows a group a4 of a sleeve contour and a corresponding collet contour when n is 3 and K is 3, the sleeve contour having a length L_s＝7L_b。

Fig. 35 shows a group B4 of three sleeve profiles and three corresponding collet profiles when n is 3 and K is 5, the sleeve profiles having the same length L_s＝9L_b。

Fig. 36 shows a group C4 of five sleeve profiles and five corresponding collet profiles when n is 3 and K is 7, the sleeve profiles having the same length L_s＝11L_b。

Fig. 37 shows a set D4 of seven sleeve profiles and seven corresponding collet profiles when n is 3 and K is 9, the sleeve profiles having the same length L_s＝13L_b。

Fig. 38 shows a group B5 of two sleeve profiles and two corresponding collet profiles when n-4 and K-4, the sleeve profiles having the same length L_s＝9L_b。

FIG. 39 showsA group C5 of four sleeve profiles and four corresponding collet profiles is shown when n is 4 and K is 6, the sleeve profiles having the same length L_s＝11L_b。

Fig. 40 shows a group D5 of six sleeve profiles and six corresponding collet profiles when n is 4 and K is 8, the sleeve profiles having the same length L_s＝13L_b。

Fig. 41 shows a set B6 of a sleeve contour and a corresponding collet contour when n is 5 and K is 3, the sleeve contour having a length L_s＝9L_b。

Fig. 42 shows a group C6 of three sleeve profiles and three corresponding collet profiles when n is 5 and K is 5, the sleeve profiles having the same length L_s＝11L_b。

Fig. 43 shows a group D6 of five sleeve profiles and five corresponding collet profiles when n is 5 and K is 7, the sleeve profiles having the same length L_s＝13L_b。

Fig. 44 shows a group C7 of two sleeve profiles and two corresponding collet profiles when n is 6 and K is 4, the sleeve profiles having the same length L_s＝11L_b。

Fig. 45 shows a group D7 of four sleeve profiles and four corresponding collet profiles when n is 6 and K is 6, the sleeve profiles having the same length L_s＝13L_b。

Fig. 46 shows a group C8 of a sleeve contour and a corresponding collet contour when n is 7 and K is 3, the sleeve contour having a length L_s＝11L_b。

Fig. 47 shows a group D8 of three sleeve profiles and three corresponding collet profiles when n is 7 and K is 5, the sleeve profiles having the same length L_s＝13L_b。

Fig. 48 shows a set D9 of two sleeve profiles and two corresponding collet profiles when n is 8 and K is 4, the sleeve profiles having the same length L_s＝13L_b。

Fig. 49 shows a sleeve contour and a counterpart when n is 9 and K is 3Group D8 of collet profiles, wherein the sleeve profile has a length L_s＝13L_b。

Table 1 below summarizes the profile sets shown in fig. 22 to 49. It can be seen that by limiting the casing profile length to 7L_b、9L_b、11L_bAnd 13L_bA total of 122 casing profiles and 122 corresponding collet profiles are available and used for downhole fracturing.

TABLE 1

In embodiments where two or more spool valves 100 having the casing profiles described above are used in a pipe string, the sequence of casing profiles may need to be arranged as follows:

(a) the spool valve should have different sleeve profiles; in other words, for any two spools, n, K, and m₁Should be different;

(b) length L_sThe shorter slide valve should be installed at length L_sThe wellhead side of the longer spool valve; in other words, the spool valve with the smaller (n + K) should be located on the wellhead side of the spool valve with the larger (n + K);

(c) for the length L_sIdentical slide valve, S_rThe larger spool valve should be installed at S_rThe wellhead side of the smaller spool valve; in other words, for a spool valve with the same (n + K), the spool valve with the larger n should be located on the wellhead side of the spool valve with the smaller n; and is

(d) Spool valves of the same profile set (i.e., having the same n and the same K but different m)₁The spool valve) may be arranged in any order.

In other words, a spool valve having a "lower" category letter (e.g., "A") (i.e., having a shorter sleeve profile length L_sSlide valve of (D)) should be located in a slide valve having a "higher" category letter (e.g., "D") (i.e., having a longer sleeve profile length L_sThe spool valve). For spool valves having the same type of letter (i.e., having the same sleeve profile length L)_sThe spool valve) the spool valve with the smaller set number (e.g., "a 1") should be located downhole of the spool valve with the larger set number (e.g., "A3"). FIG. 50 shows one example of a tubing string (e.g., a casing or tubing string) having a plurality of spools 100 arranged in the manner described above.

In some alternative embodiments, t is equal to or close to 1, and the groove and its corresponding ridge have a maximum length difference L_bThus, the two "adjacent" sleeve profiles and the collet profile are not mutually exclusive.

That is, the collet profiles may be received not only in the matching sleeve profile, but also in sleeve profiles having the same category letter, the same group number, and "adjacent" profile number (i.e., differing by 1). For example, the collet profile C (A1-2) (i.e., C [0,6,2]) may fit into the previous and next sleeve profiles S (A1-1) and S (A1-2) (i.e., S [0,6,1] and S [0,6,3]), but may not fit into the other sleeve profiles (e.g., S (A1-4)) in profile set A1.

In other words, the collet profiles can fit into the previous and next sleeve profiles in the same profile set, but not into the other sleeve profiles in the same profile set. That is, the collet profile C [ n, K, i ] can fit into the sleeve profiles S [ n, K, i +1] and S [ n, K, i-1], but cannot fit into other sleeve profiles (i.e., sleeve profiles S [ n, K, j ]), where j ≠ i, j ≠ i +1 and j ≠ i-1).

Thus, in an embodiment where t 1 and two or more spool valves 100 having sleeve profiles as shown in fig. 22 to 49 are used on a pipe string, the sequence of the sleeve profiles needs to be arranged as follows:

(b) within each contour group, if | j₁-j₂If | is less than or equal to 1, two casing contours S [ n, K, j ] cannot be used on the same string₁]And S [ n, K, j ]₂](ii) a In other words, for any two having the same n and the same KA slide valve, m₁The difference between them needs to be greater than 1;

(c) length L_sThe shorter slide valve should be installed at length L_sThe wellhead side of the longer spool valve; in other words, the spool valve with the smaller (n + K) should be located on the wellhead side of the spool valve with the larger (n + K);

(d) for the length L_sIdentical slide valve, S_rThe larger spool valve should be installed at S_rThe wellhead side of the smaller spool valve; in other words, for a spool valve with the same (n + K), the spool valve with the larger n should be located on the wellhead side of the spool valve with the smaller n; and is

(e) Spool valves of the same profile set (i.e., having the same n and the same K but different m)₁The spool valve) may be arranged in any order.

In some alternative embodiments, the sleeve profile and collet profile described above may be cascaded or cascaded with other suitable profiles to achieve an expanded profile. For example, FIG. 51 shows an expanded set of sleeve and collet profiles obtained by connecting the same profile 286 between the profiles in profile set A1 and stop ring 192. As shown in fig. 52, in some embodiments, the same profiles 286 may be concatenated uphole of the profiles in group a1 to obtain an expanded profile.

In some embodiments, contours in the same group may be concatenated with different contours to obtain an expanded contour. For example, FIG. 53 shows the profile of group A1 concatenated with the first four profiles in group B2 to obtain an expanded profile.

In the above described embodiment, the casing profile is located on the inner surface of the casing body 152 so that the stop shoulder 194 of the stop ring 192 is located downhole thereof. In some alternative embodiments as shown in fig. 54-56, the sleeve profile includes a profile portion on the inner surface of the sleeve body 152 and a profile portion on the inner surface of the protection sleeve 154 as described above, such that the stop shoulder 194 of the stop ring 192 is in the sleeve profile.

Accordingly, the collet 200 may have a collet profile extending over the sleeve body 152 and the protection sleeve 154 for mating with the sleeve profile. To ensure that the front or downhole portion of the collet 200 passes smoothly over the stop ring 192, each projection 292 on the collet 200 that matches the contour on the protection sleeve 154 has an obtuse angle on its downhole side.

The profile on the protective sleeve 154 may have any suitable shape and may be combined with a sleeve body 152 of any suitable profile, such as any of the profiles shown in fig. 22-49. For example, FIGS. 54-57 illustrate a fiber having a length of 2L_bAnd the protective sleeves 154 of the slots 294 and respectively engage the profile groups a1, B1, C1, and D1 shown in fig. 22-25. Accordingly, the collet profile of the collet 200 includes a length L_bA protrusion or ridge 292 for mating with the groove 294.

In some embodiments, the groove 294 can have other suitable lengths. For example, FIGS. 58-61 show a lens having a length of 3L_bAnd the protective sleeves 154 of the slots 294 and respectively engage the profile groups a1, B1, C1, and D1 shown in fig. 22-25. Accordingly, the collet profile of the collet 200 includes a length of 2L_bA protrusion or ridge 292 for mating with the groove 294.

In some embodiments, the contour on the protection sleeve 154 may include one or more grooves and/or one or more ridges.

In some embodiments, the profile on the protective sleeve 154 may be a profile selected from those shown in fig. 22-49. For example, a set of expanded profiles may be obtained by concatenating the profiles in profile group a1 with the first four profiles in profile group B2, where the first four profiles in profile group B2 are located downhole on the stop ring 192 or the protection sleeve 154.

As shown in fig. 62, in some alternative embodiments, a casing profile (e.g., a casing profile in profile group a 1) may be located downhole of the stop ring 192. Thus, the stop shoulder 194 is located on the uphole side of the casing profile. In these embodiments, each projection on the collet 200 has an obtuse angle on its downhole side to ensure that the collet 200 passes smoothly through the snap ring 192.

As described above and shown in fig. 15A and 15B, the sliding sleeve 126 of the spool valve 100 may be pressure actuated by the ball 242 and collet 200 to an open position to open a fluid port for fracturing, wherein the splines 218 of the collet 200 can be pressure actuated to expand radially outward upon application of fluid pressure, and when the collet profile 212 engages the shoulder 194 of the snap ring 192, compression of the collet causes the splines 218 to expand radially outward to further engage the sliding sleeve 106 to further increase the engagement to further increase the pressure resistance. Fig. 63A to 63F show more details of the radially outwardly expanding collet profile 212.

Referring to FIG. 63A, for ease of illustration,

sleeve grooves

184A and 184B are considered to have the same inner diameter, and

collet ridges

222A and 222B are considered to have the same outer diameter.

Depth H of wellhead casing groove 184A_sg1Measured radially between its outermost surface (i.e., its "bottom surface") and its innermost uphole edge (i.e., its uphole "top" edge). Height H of the cannula ridge 232_srIs measured radially between its innermost surface (i.e., its "top surface") and its outermost edge (i.e., its "bottom" edge). Depth H of downhole casing slot 184B_sg2Is measured radially between the outermost surface and the innermost downhole edge, and its innermost downhole edge is also the innermost edge of the stop shoulder 194.

Similarly, height H of wellhead collet ridge 222A_cr1Measured radially between its outermost surface (i.e., its "top face") and its innermost uphole edge (i.e., its uphole "bottom" edge). Depth H of the clip groove 234_cgIs measured radially between its innermost surface (i.e., its "bottom surface") and its outermost edge (i.e., its "top" edge). Height H of downhole collet ridge 222B_cr2Measured radially between its outermost surface (i.e., its "top face") and its innermost downhole edge (i.e., its downhole "bottom" edge).

In some embodiments as shown in FIGS. 63A-63C, H_sg1＝H_sg2＝H_sr＝H_sAnd H_cr1＝H_cr2＝H_cr. Referring to FIG. 63B, to allow the collet profile 212 to expand radially outward when the collet profile 212 engages the sleeve profile 182, it is necessary that each of the

sleeve grooves

184A and 184B and the collet groove 234 and the corresponding

collet ridges

222A and 222B and each of the sleeve ridges 232A gap is maintained between one. In other words, H_s-H_cr>0、H_cg-H_cr>0 and₂>0. thus, in these examples, H_s>H_cr、H_cg>H_crAnd is₂>0。

In some embodiments, H_sg1＝H_sg2＝H_sr＝H_sAnd H_cr1＝H_cr2＝H_crAnd the collet groove 234 is located at a position about the longitudinal center of the collet profile 212, the collet groove 234 is the most pronounced portion of expansion when the splines 218 expand or flex radially outward (see fig. 63C). In these examples, H is required_s>H_cr、H_cg>H_crAnd is₂>0. Preferably, the gap between the collet groove 232 and the sleeve ridge 232 is greater than or equal to the gap between the sleeve groove 184A/184B and the corresponding collet ridge 222A/222B. In other words, H_s-H_cr>0、H_cg-H_cr>0、H_cg-H_cr≥H_s-H_crAnd is₂>0. Thus, in these examples, H_cg≥H_s>H_crAnd is₂>0. In some embodiments, H is preferred_cg＝H_s>H_crAnd is₂>0 so that when the collet profile 212 expands radially outward in the sleeve profile 182, the collet ridges 234 can fully engage the sleeve ridges 232 and eliminate gaps therebetween.

After the collet 200 is engaged with the sliding sleeve 106, further pressure from the uphole side thereof can drive the collet 200 further downhole, forcing the splines 218 to expand or flex radially outward and further and to a greater extent into mating engagement with the sliding sleeve 106, as shown in fig. 63B and 63C.

In some embodiments as shown in fig. 63D-63F, the depth of the wellhead casing groove 184A is the same as the height of the casing ridge 232. However, the depth of the downhole casing slot 184B is greater than the depth of the uphole casing slot 184A. That is, H_sg1＝H_sr＝H_sAnd H_sg2>H_s. The height of the

collet ridges

222A and 222B and the depth of the collet slots 234 are the same.That is, H_cr1＝H_cr2＝H_cr。

Referring to FIG. 63E, in these embodiments, H_cg+H_sg2-H_cr-H_s>0、H_sg2-H_cr>0 and₂>0 to allow the collet profile 212 to expand radially outward when the collet profile 212 engages the sleeve profile 182.

In some embodiments, H_sg1＝H_sr＝H_s、H_sg2>H_s、H_cr1＝H_cr2＝H_crAnd the collet groove 234 is located at a position around the longitudinal center of the collet profile 212, the collet groove 234 is the most pronounced portion of expansion as the splines 218 expand radially outward (see fig. 63E).

In these examples, H_cg+H_sg2-H_cr-H_s>0、H_sg2-H_cr>0 and₂>0. preferably, the gap between the collet groove 232 and the sleeve ridge 232 is greater than or equal to the gap between the sleeve groove 184A/184B and the corresponding collet ridge 222A/222B. In other words, H_cg+H_sg2-H_cr-H_s≥H_sg2-H_cr. Thus, in these examples, H_sg2>H_cr、H_cg≥H_sAnd is₂>0. In some embodiments, H is preferred_sg2>H_cr、H_cg＝H_sAnd is₂>0 so that when the collet profile 212 expands radially outward in the sleeve profile 182, the collet ridges 234 can fully engage the sleeve ridges 232 and eliminate gaps therebetween.

Although some embodiments have been described above with reference to the accompanying drawings, it will be understood by those skilled in the art that various changes and modifications can be made without departing from the scope of the invention.

For a complete definition of the invention and its intended scope, the summary of the invention and the appended claims are to be read and considered in connection with the detailed description herein for illustrative purposes and the accompanying drawings.

Claims

1. A plurality of spool valves, each spool valve comprising:

a valve body having a longitudinal bore therethrough and one or more fluid ports on an uphole portion of a sidewall of the valve body; and

a sliding sleeve received in the longitudinal bore of the valve body and movable between an uphole closed position closing the one or more fluid ports and a downhole open position opening the one or more fluid ports, the sliding sleeve including a longitudinal bore;

S_r＝L_a+nL_b,

S_g1＝m₁L_b+(1-)L_a,

S_g2＝m₂L_b,

m₁+m₂＝K,

Wherein the longitudinal length L of the casing profile_sAt least:

L_s＝L_a+(n+K)L_b；

and wherein for any two spools of the plurality of spools, n, K, and m thereof₁At least one of which is different.

2. The spool valve of claim 1, further comprising a stop shoulder.

3. The spool valve of claim 2, wherein the stop shoulder is located downhole of the sleeve profile.

4. The spool valve of claim 2, wherein the stop shoulder is located in the sleeve contour.

5. The spool valve of claim 2, wherein the stop shoulder is located on a wellhead side of the sleeve profile.

6. A slide valve as claimed in any one of claims 1 to 5, wherein L_a＝L_b。

7. The spool valve of claim 6, wherein t₁＝t₂＝t。

8. The spool valve of claim 7, wherein 1> t > 0.

9. The spool valve of claim 7, wherein t is about 0.5.

10. The spool valve as claimed in claim 7, wherein 0.9> t ≧ 0.1.

11. The spool valve as claimed in claim 7, wherein 0.8> t ≧ 0.2.

12. The spool valve as claimed in claim 7, wherein 0.7> t ≧ 0.3.

13. The spool valve as claimed in claim 7, wherein 0.6> t ≧ 0.4.

14. The spool valve of claim 7, wherein t-0.

15. The spool valve of claim 7, wherein t-1.

16. A plurality of collets, each collet being movable through one or more apertures of the first runner and receivable in the second runner, each collet comprising:

a flexible collet profile formed by at least first and second collet ridges and a collet slot therebetween, the first and second collet ridges and the collet slot corresponding to the first and second sleeve slots and the sleeve ridge, respectively;

wherein the first and second collet ridges and the collet groove have a length C_r1、C_r2And C_gAre respectively determined by the following formula:

C_r1＝(m₁-t₁)L_b+(1-)L_b-₂,

C_r2＝(m₂-t₂)L_b,

C_g＝L_a+(n+t₂)L_b+₂,

m₁+m₂＝K,

wherein L is_a、L_bAnd is a predetermined parameter, L_a>0，L_b>0 and 1 is not less than 0, n is an integer and n is not less than 0, K is a positive integer and K>2，m₁And m₂Is an integer and m₁M is not less than 1₂>1；t₁、t₂And₂is a predetermined parameter, 1 ≧ t₁≥0，1≥t₂Is not less than 0 and₂not less than 0; and is

Wherein the longitudinal length L of the collet profile_cAt least:

L_c＝L_a+(n+K-t₂)L_b；

17. The collet of claim 16, wherein at least one of the at least one collet ridge is located on a downhole side of the stop shoulder and forms an obtuse angle between upper edges of the downhole side thereof.

18. A tubular string, comprising:

a plurality of slide valves as claimed in any one of claims 1 to 13;

(a) for any two spools of the plurality of spools, n, K, and m₁Is different;

(d) Having the same n and the same K but different m₁The spools of (a) are arranged in any order.

19. A tubular string, comprising:

a plurality of slide valves according to claim 15;

(a) for any two spools of the plurality of spools, n, K, and m₁Is different;

(e) Having the same n and the same K but different m₁The spools of (a) are arranged in any order.

20. The tubing string of claim 18 or 19, wherein the tubing string is a casing string.

21. A tubing string according to claim 18 or 19, wherein the tubing string is a tubing string for receipt in a cased or uncased wellbore.

22. A downhole system comprising:

the tubing string of any one of claims 18 to 21; and

one or more collets, each of the one or more collets being a collet as claimed in claim 16 or 17.