JP5346332B2 - Oil well finishing tool with severable tubing string blocking disc - Google Patents

Abstract

An oil well completion tool having a tubular assembly defining an elongated main passage is adapted to be connected to a multiple-section tubing string within an oil well casing. A severable plug is mounted in the tubular assembly in normal blocking relationship to the passage. A movable shear cylinder unit has a plug-severing edge operable to sever an entire central segment of the plug from a remaining peripheral portion thereof. Separate hinge structure has an elongated U-shaped leg portion connected to the central segment of the plug. The leg portion of the hinge structure, which undergoeselongation, is operable to retain the severed central segment of the plug in the main passage while allowing the central segment of the plug to bodily shift independent of and in a direction away fromthe peripheral portion of the plug. The severed central segment is received in a recess therefor in the tubular assembly wall structure in order to prevent interference of the severed central plug segment with the main passage.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of US patent application 11 / 744,605 filed May 4, 2007, which is hereby incorporated by reference. It is.

  The present invention relates to an oil well finishing tool that is disposed within a well casing between a plurality of sections of tubing strings and most generally configured to lie on top of other well tools such as packers. With this finishing tool, for example, the tubing string can be shut off to allow attachment of a packer or the like, and then the tubing string can be completely opened for production from a well.

  Normally, when an oil or gas well is drilled in a hydrocarbon-producing formation, its borehole is then surrounded by a string of relatively large diameter pipe sections, commonly referred to as well casings. Isolated from. The section of the casing may be, for example, about 5 to about 9 inches in diameter. In order to provide a barrier between the outside of the casing and the inside of the borehole of the well, cement is most often placed around the casing over its entire length. Cement acts to prevent movement of fluid and gas between underground layers.

  Tubing strings assembled from small diameter individual pipe sections connected end to end are usually inserted into wells in the casing. During the finishing of a standard casing well, a tool such as a packer is installed at the end of the tubing string to isolate the space called the annulus between the inside of the casing and the outside of the tubing string. Will. Used by many types of well packers with elastomer sleeves and bladders that can be engaged with the contact surface of the casing, either expanded mechanically, by hydraulic expansion, or by the use of wireline sets Is done. A mechanical packer is generally operated by the rotation of a string, and the rotation presses the sleeve so that its outer surface is in close contact with the casing.

  The hydraulic packer makes the mechanical packer impractical, especially because the well casing has a large number of bends and is not substantially straight over its entire length or needs to be installed in a horizontal well. In doing so, it provides many advantages in installation and operation. In the case of a hydraulic packer, it is necessary to equip the casing under the packer with a plug in order to resist the water pressure required to install the packer bladder. Once the packer is installed, the plug must be fully opened to begin oil production. A hydraulic packer is just one example of a downhole tool that functions by requiring pressurized hydraulic fluid.

  In well stimulation operations, it is common to surge the formation to remove debris from the formation and improve hydrocarbon flow. Surging is achieved by reducing the pressure in the tubing string to a pressure less than the formation pressure and quickly equalizing this pressure difference. Another example of well stimulation includes increasing the fluid pressure in the tubing string to a value substantially above formation pressure. When the pressure in the tubing string is released quickly compared to the formation pressure, cracks are formed in the formation and hydrocarbons can be produced without passing through rocks damaged by well drilling and finishing operations.

  In these examples, as with other typical finishing processes, the plug is completely removed from the well channel immediately after it has begun to function as a tool or the stimulation process has begun. It is desirable.

  The prior art uses many typical tools that help in the installation of packers and similar well annulus separators. Many of these tools utilize plugs to temporarily block the tubing string so that water pressure on the packer or the like is applied to the tools. Some plugs operate on a wireline and are installed in place. After pressurization, the line is wound up and the plug is pulled up to the ground. This type of work has been found to be time consuming and poses risks associated with well interference.

  Other well casing separation tools include tubing string breakers such as glass or ceramic plugs. These plugs are opened by dropping the bar from the ground and damaging the plug, or by over-pressurizing and damaging the plug. The use of these types of plugs raises many unresolved issues and safety concerns. These plugs are subject to fragile material, resulting in micro cracks resulting from rough handling at the well surface, improper assembly in the tool, or resistance problems, resulting in greatly reduced pressure ratings and predictions Causes impossible plug damage.

  The pressure responsive rupture valve of US Pat. No. 3,779,263, which is particularly effective for surging oil wells, is equipped with a tubular cutting sleeve that is moved by a pressure responsive tubular piston. Its main valve passage is in direct communication with the chamber of the piston. Pressurization of the piston chamber by fluid introduced into the valve passage causes the cutting sleeve actuated by the piston to move towards a rupture disk that normally blocks the passage through the valve. The disk is deeply provided with a series of cut lines oriented in the radial direction. When the multi-angle cutting edge of the cutting sleeve engages the disc, the disc breaks like a series of individual petal-like pieces that fold outward toward the wall structure of the valve.

  The valve of U.S. Pat. No. 4,609,005 uses a tubular cutting mandrel that breaks a portion of the disk that normally blocks the passage through the valve housing. This cutting mandrel leaves a narrow uncut portion due to an elongated gap when manipulating its edges. As is apparent from FIG. 2 of the drawing of US Pat. No. 4,609,005, the mandrel is in a fully actuated position, partly due to the spacing between the mandrel and the adjacent valve housing wall. It is not possible to ensure that the required drift aperture is maintained through the opened valve.

  A well annulus pressure responsive surge tool is described in US Pat. No. 4,658,902. A tubular cutting mandrel mounted within the tool housing and movable by another power mandrel is operable to engage and cut a C-shaped section of a fragile disc that normally blocks the passage through the tool. . The cutting mandrel is provided with an elongated gap extending in the longitudinal direction, leaving an uncut disc piece. It is said that the divided part of the disk is bent laterally by the mandrel in the same manner as the disk piece and is held between the outer surface of the mandrel and the inner surface of the housing. One or more pins must be cut before the power mandrel can move the cutting mandrel toward the disk. Since the cutting mandrel is provided with an elongated gap, the mandrel must be moved over a distance significantly longer than the length of the mandrel gap. In order to move the mandrel over long distances, a two-stage mandrel structure is required, resulting in a complex mechanism with pins that control the release of the mandrel, and increased input costs and comprehensive reliability. Sex is sacrificed.

  In PCT application PCT / GB97 / 02043, a plug for an oil or gas well borehole ruptures to open the tubing string when pressurized above a certain level. It is described as an alternative. Some of these early plugs break and are released from the tubing string, which becomes an unwanted piece of equipment at the bottom of the well that later causes problems. The plug of application PCT / GB97 / 02043 consists of a screw-type box end, a screw-type pin end, an upper tubular body part, and a lower tubular body part. A steel barrier plate machined from the lower body part extends across the central hole in the tubing. A cutter having a tapered cutting blade is fixed to the lower body part by a cutting pin. The cutter is moved by a movable piston sleeve that is temporarily held in the retracted position of the lower body part by a fixed dog and a fixed sleeve with a gap. By circulating pressure within the tubing, the piston sleeve moves up and down against the movement of the spring until the slide bolt enters a predetermined position on the sleeve with clearance. As a result, the fixed dog is released, the sleeve can move downward and engage with the cutter, the cutting pin is cut, and the cutter collides with the blocking plate. Since only a part of the plate is cut, the cut part is bent outward by the cutter and enters the concave section at the end of the box. This tool is very large and can only be used with large diameter casings. The functional reliability of this very complex and expensive structure is inherently problematic in difficult situations that lie very deep in the borehole of the well, and this unit does not fit the majority of wells And

  A tubing string separation tool using a fragile glass disk is described in US Pat. No. RE39,209. Due to the presence of the glass disk, the well fluid flows at an increased pressure from the ground surface into the tubing string, resulting in a fluid load that allows packers and other attachments to be installed hydraulically in a conventional manner. be able to. When a packer or other accessory is installed and production fluid recovery is required from the formation, increasing the fluid pressure in the wells in the tubing string overcomes the cutting pin resistance and crushes the glass disk A pressurized fluid load is applied to the piston that moves downward with sufficient force. Fragments that result from disk breakage can form a glass lump that is ¼ to ½ inch in diameter. This type of debris should be avoided due to various close downhole resistance. If the use of a metal rod is intended for crushing the glass disc, the bending of the tubing string actually impedes the downward movement of the rod, or the rod has sufficient impact to break the glass disc. To the extent that it does not have power, it will prevent the rod from moving.

  In US Pat. No. 5,996,696 assigned to the assignee, a rupture disc is used to block the tubing string flow path so that the integrity of the tubing string connection can be tested. Yes. After confirming that none of the tubing sections are leaking, the disc will be ruptured by applying a predetermined overpressure to the disc through the string. All pipe sections of the tubing string have the required drift aperture for a particular pipe inner diameter. The tubing string integrity test apparatus of US Pat. No. 5,996,696 is satisfactory in many applications, but in some cases, the central section of the disc that bursts under overpressure is fully open. It has been found that this test device cannot provide the required drift aperture by failing to bend against the device housing.

  The oil well finishing tool of the present invention eliminates the problems posed by previously available tools. The tool includes an axially extending tubular assembly that defines a long main passage and includes a severable plug that is attached to the tubular assembly that is normally in a blocking relationship with respect to the axial passage. The movable cutting cylinder unit in the tubular assembly has a plug cutting edge that is operable to cut the entire central segment of the plug from its remaining peripheral portion when the cutting cylinder unit is moved over the plug cutting distance. The independent long hinge structure in the assembly has a long inner leg portion fixed to the central segment of the plug facing the cutting cylinder unit and an outer leg portion joined to an annular part connected to the peripheral portion of the plug. Have. The long leg portion of the hinge structure is connected to the annular part and is operable to hold the plug in the assembly body after the central segment of the plug has been severed. The hinge structure allows the entire split central plug segment to move away from the remaining annular peripheral portion of the plug and independently of the annular portion. An L-shaped tab is placed on the periphery of the central section of the plug, opposite the hinge structure. This tab is received in the cut-out of the plug split edge of the cutting cylinder and maintains the alignment between the leading edge portion of the cutting cylinder and the central segment of the plug.

  The severable shutoff plug is preferably attached to the tubular assembly of the tool between the lower sub and the housing connected to the upper sub. The movable cutting cylinder unit in the housing can be moved over the plug cutting distance by a single-acting piston structure that forms part of the housing. The tapered plug cutting edge of the cutting cylinder unit functions to continuously cut the entire central segment of the plug from the remaining peripheral portion of the plug. The long leg portion of the hinge structure keeps the split central segment of the plug in the main passage of the assembly as the hinge structure extends, so that the central plug segment moves away from the remaining peripheral portion of the plug, and It is possible to move independently from this peripheral part. A hinge having a long leg portion which is independent of the central segment of the plug but is connected to this segment and which can be extended when the central segment of the plug is split by the cutting cylinder unit and bent laterally. By providing, the disconnected section of the plug can move in the longitudinal direction and the lateral direction of the tool's main passageway into the recess of the tool's wall structure. As a result, the severed portion of the plug does not block the main passage, ensuring that the required drift aperture throughout the tool is maintained.

  The wall structure of the tool tubular assembly and the movable cutting cylinder unit jointly provide a chamber that has a piston face facing the plug that normally blocks the passage through the tubular assembly and is normally at atmospheric pressure. When the fluid in the chamber is pressurized and thereby exerts sufficient force on the piston face to move the cutting cylinder unit, the leading end of the tapered plug cutting edge of the cutting cylinder unit will initially cause the central segment of the plug to To sever the plug. This severing continues over the outer periphery of the plug until the entire central segment of the plug is separated from its peripheral portion. It is desirable to provide a cavity (indentation) on one side of the plug so that it is aligned with the leading end of the cutting cylinder unit that first contacts the plug surface. This cavity may have a central space deeper than the cavity space on either side of it, facilitating the start of the cutting of the central segment of the plug by the cutting cylinder unit.

  Any of a number of instruments operable by pressure or force may be provided to control the movement of the cutting cylinder unit over the plug cutting distance. The instrument may be a rupture disc or a knockout plug that is actuated by KOBE's drop bar. The use of a rupture disc in communication with the piston chamber in the wall structure of the tool assembly or in the cutting cylinder unit allows the cutting cylinder unit to be actuated by atmospheric pressure or differential pressure controllable from the ground surface. Because the pressure response can be selectively controlled by selecting a rupture disc having a predetermined rupture characteristic, it is preferable to use a rupture disc for this purpose.

  In addition to vertical well casings, the tools of the present invention are also useful in one or more horizontal casing sections that exit from vertical wells that extend to the surface. The tool of the present invention is particularly effective in many applications in wells, since no debris remains in the hole, either vertically or horizontally, after opening the plug to allow production from the well.

  Another important feature of the present invention is that the pressure resistance characteristics of the interrupting plug can be selected without adversely affecting the complete opening of the plug by changing the thickness of the plug, the material of construction and the overall shape of the plug. It is possible to change it.

  Most finishing tools of the prior art operate under specific parameters and operating procedures and do not allow tool changes or arbitrary structures to accommodate changes in well conditions or procedures.

  Oil well finishing tools are designed in most common operations such that the atmospheric pressure chamber that receives the internal piston is sealed against the annulus pressure around the piston and piston housing. Thus, the atmospheric pressure chamber is not adversely affected by standard annulus pressure.

  When using the well finish tool of the present invention, if a very high pressure well condition needs to be accommodated, the pressure differential, i.e., annulus, is used to prevent damage due to over pressurization of the tool housing and piston structure. The difference between the pressure of the tube and the pressure in the tubing string and hence the tool must be fully compensated. Such high pressure compensation must be performed while maintaining complete control throughout the selective operation of the tool. In wells with excessive high pressure, the difference between the well's annulus pressure and atmospheric pressure can be large enough to break the tool housing and the cutting cylinder wall of the piston in the direction toward the inside of the atmospheric pressure chamber. In order to prevent such possible negative and destructive events, the tool housing should be lined up to reduce the pressure differential between the inside of the tool and the surrounding annulus to a mechanically acceptable level. May be provided, or the piston may be provided with a hole for pressure compensation.

  Since the amount of pressure required to activate the tool is a controllable parameter, pressurize from the ground surface to the tubing or casing string at a level well above the annulus or tubing pressure to activate the tool as needed be able to.

FIG. 2 is a partial longitudinal cross-sectional view of a tubing string in which an oil well finishing tool assembly according to the present invention is disposed under a schematically illustrated packer. FIG. 6 is a longitudinal cross-sectional view of one embodiment of a finishing tool assembly illustrating a cutting cylinder unit in a normal position above a severable plug attached to a tubular assembly and normally in a blocking relationship with the assembly axis. . FIG. 3 is a longitudinal cross-sectional view of the embodiment of FIG. 2 showing the position of the cutting cylinder unit after moving over the plug cutting distance. It is a perspective view of the movable cutting cylinder unit of a finishing tool assembly. FIG. 6 is an enlarged partial longitudinal sectional view illustrating the position of the cutting cylinder unit before cutting the central segment of the severable plug attached to the tool assembly. FIG. 6 is an enlarged partial longitudinal sectional view similar to FIG. 5 illustrating the cutting cylinder unit in a post-actuation position after dividing the central segment of the plug. FIG. 7 is an enlarged partial longitudinal sectional view of the portion shown in FIG. 6 having a 90 ° relationship to the depiction of FIG. 6. FIG. 6 is an enlarged cross-sectional view of a tubular finishing assembly along a horizontal plane illustrating the bottom of the severable plug. It is an expanded sectional view in alignment with the same line as FIG. 8 without the plug and hinge which can be cut | disconnected attached. FIG. 6 is a top perspective view of a severable plug with a hinge structure attached to a central segment. It is a bottom perspective view of the severable plug shown in FIG. It is a disassembled bottom perspective view of a severable plug in which a hinge part and a corresponding annular support part are attached to a plug body. FIG. 6 is a longitudinal cross-sectional view of a second embodiment of a finishing tool assembly. FIG. 7 is a longitudinal cross-sectional view of a third embodiment of a finishing tool assembly in which a hole is optionally provided in the piston in communication with an atmospheric pressure chamber that reciprocally accommodates a portion of the piston during movement of the piston. FIG. 15 is a cross-sectional view taken substantially in the direction of the arrows of FIG. FIG. 6 is a longitudinal sectional view of a fourth embodiment of a finishing tool assembly. FIG. 10 is a longitudinal cross-sectional view of a fifth embodiment of a finishing tool assembly.

  One preferred embodiment of the oil well finishing tool 20 of the present invention is shown in the front view of FIG. 1 of the drawings and is attached to a multi-section tubing string 22 below the illustrated packer 24 in an oil well casing 26. It is drawn as follows. Tool 20 includes a tubular assembly 28 having an upper threaded box sub 30 configured to receive the threaded end of tubing section 22a. The housing 32 of the assembly 28 is connected to the top sub 30 in a screw type, and is installed between the sub 30 and the lower screw type pin sub 34. The pin sub 34 is coupled to the housing 32 in a screw manner and is configured to be screwed to the section 22 b of the tubing string 22. The cutting cylinder unit 36 is movably attached to the housing 32 so as to move in the axial direction of the main passage 38 of the tool 20. A severable plug is indicated generally at 40 and is mounted between adjacent ends of the housing 32 and the lower sub 34. The plug 40 in the normal position blocks the main passage 38 of the tool 20. Plug 40 is preferably Inconel, stainless steel, or an equivalent metal. The tapered plug dividing edge 42 at the lowermost end of the cutting cylinder unit 36 includes a leading edge segment 42a closest to the adjacent surface of the plug 40 and an opposing trailing edge segment 42b in the arrangement of the unit 36 shown in FIG. Each of the trailing edge segments is at an angle of about 7 ° to about 18 °, more preferably an angle of about 11 ° to about 16 ° with respect to the longitudinal axis of the passage 38; Most preferred is an angle of about 15 °. Edge segments 42a and 42b jointly define a circular tapered plug break edge. In this respect, it is also preferred that the edge 42 is chamfered from the outer diameter to the inner diameter of the cutting cylinder unit 36 at an angle of about 15 °.

  Plug 40 includes a rigid circular body including a central flat section 46 with an outer tapered section 48 that communicates with a stepped annular peripheral portion 50 having an inner circular segment 50a and an outer circular segment 50b. An assembly having 44. As can be seen, for example, in FIG. 5, the surface 52 of the plug 40 opposite the section 46 is essentially flat except for an edge portion 54 that extends circumferentially around its periphery.

  The hinge structure shown generally at 56 in the assembly 28 includes an annular component 58 that is secured to the outermost stepped peripheral surface 50b of the plug 40. The long L-shaped portion 60 of the hinge structure 56 has an outermost generally U-shaped section 62 and an outer leg portion 64. U-shaped section 62 has leg portions 66 and 68 that are joined to outer leg portion 64. The leg portion 66 of the section 62 is integrated with the annular part 58. Plug 40 and hinge structure 56 may be fabricated from any of a number of metals conventionally used in the manufacture of rupture discs, with Inconel being preferred, but as an example, 316 stainless steel can also be used.

  Although a preferred embodiment of a plug 40 having an essentially flat facing surface defining a central section 46 of the plug is shown in the figure, the severable plug is suitable for use in well pressure profiles and oil well finishing tools 20. Depending on, it may have a central section curved into a concave-convex shape with a concave surface facing either upstream or downstream of the pressure source.

  The lower sub 34 includes a cavity (cavity portion) 34 a having a thread groove on the inside and configured to receive an end portion 32 a having a thread groove on the outside of the housing 32. The lowermost end 32 a of the housing 32 includes an outermost annular groove 70 that complementarily accommodates the edge portion 54 of the plug 40. The edge portion 54 plays a role of suppressing the bending of the main body 44 under the flow pressure to the main body 44. Similarly, as can be seen from FIG. 5, the plug 40 is retained between the lowermost end portion 32 a of the housing 32 and the inner groove portion 34 b extending in the circumferential direction of the lower sub 34. Proper tightening of the threaded interconnection between the housing 32 and the sub 34 provides a metal-to-metal seal between the plug 40, the housing 32, and the sub 34 that does not cause leakage, so that over time. It is not necessary to equip a deteriorated O-ring gasket. The cylindrical interior of the sub 34 has a cut segment 34 d for receiving a section 62 of the hinge structure 56.

  The cutting cylinder unit 36 has a long annular body portion 72 that is received in a long recess 74 that extends circumferentially in the wall structure 76 of the sub 30 and a long annular recess 78 in the wall structure 80 of the housing 32. The concave portion 78 of the housing 32 is stepped and has a larger diameter than the concave portion 74. The peripheral piston projection 82 extending outward from the columnar wall 36a of the cutting cylinder unit 36 is in contact with the surface of the recess 78, has a space in the axial direction, and extends in the circumferential direction. 86 are each defined in conjunction with the surface. The chamber 86 has a larger space than the chamber 84, and is generally at atmospheric pressure in the embodiment of FIGS.

  The L-shaped tab 88 attached to the peripheral portion of the surface 52 of the plug 40 engages with the lowermost end portion of the cutting cylinder unit 36. The tab 88 has a leg portion 88 a attached to the surface 52 of the plug 40 and an outwardly directed leg portion 88 b received in a cutout 89 in the lowermost end 36 b of the cutting cylinder unit 36. As can be seen from FIG. 11, the leg portion 88 b of the tab 88 is bent laterally to complementarily engage the bevel 36 c of the cutout 89. The leg portion 88b of the tab 88 has a width equal to the width of the cut surface of the cutout 89, whereby the side ends of the leg portion 88b engage the opposite side of the cutout 89. The wall section 36c of the lowermost end 36b of the cutting cylinder unit 36 has a thickness where it is aligned with the tab 88 to accommodate the outer end extension 88b, as illustrated in FIGS. Has been reduced.

  During assembly of the oil well finishing tool 20, the cutting cylinder unit 36 is inserted into the housing 32, and the leg portion 88 b of the tab 88 is formed on the outer surface of the cut wall section 36 c in which the thickness of the lower end 36 b of the cutting cylinder unit 36 is reduced, It is accommodated between the inner surface of the housing 32. The bending of the cross section of the leg portion 88 b of the tab 88 substantially conforms to the structure of the lateral slope 36 c of the outermost end 36 b of the cutting cylinder unit 36. During insertion of the cutting cylinder unit 36 into the tubular assembly 28, the engagement of the side end of the leg portion 88b of the tab 88 and the edge 89a of the opposing cutout 89 causes the upper box sub 30 to be screwed in place. This prevents rotation of the cutting cylinder unit 36 in the passage 38 as a result of the torque applied to the piston. Accordingly, the leading edge segment 42a of the cutting cylinder unit 36 maintains correct alignment with the portion 40a of the plug 40 not only during installation but also during movement of the cutting cylinder unit 36 during operation.

When the oil finishing tool 20 is subjected to high downhole pressure, which can be greater than or equal to 69.0 MPa ( 10,000 psi ) , the central section 46 of the plug 40 is somewhat curved in the direction of the pressure applied to the plug 40. Even when the central section 46 is curved to some extent by the high pressure fluid in the well, the opposing side ends of the leg portions 88b of the tab 88 remain engaged with the opposing edges 89a of the cutout 89. Accordingly, the cutting cylinder unit 36 rotates within the housing 32 and the edge segment 42 a of the edge 42 is not moved from a predetermined correct alignment position with respect to the section 46 of the plug 40.

  The piston shoulder 90 above the projection 82 faces the chamber 84, while the shoulder 92 below the projection 82 faces the chamber 86. A pair of tubular instruments 94 that are aligned with the chamber 84 and screwed to opposite sides of the wall 36a of the cutting cylinder unit 36 are preferably ruptured by pressure increase and in communication with the passage 38 of the tubular assembly 28. Each has a rupturable portion 96 that includes a disc. When the fluid pressure in the passage 38 of the tubular assembly 28 increases sufficiently to rupture the disk 96, the fluid pressure in the chamber 84 acting on the piston shoulder 90 causes the cutting cylinder unit 36 to move toward the plug 40. Move to. Since chamber 86 is at atmospheric pressure, chamber 86 does not exhibit any significant resistance to the pressure applied to shoulder 90 when disc 96 ruptures.

The rupture disc 96 is preferably provided in a wide pressure range with an increasing interval of 1.38 MPa ( 200 psi ) so that an appropriate rupture disc can be selected according to the state and operation of the well. Generally, a rupture disc is selected that requires a fluid pressure of at least about 24.1 MPa ( 3500 psi ) to rupture the disc 96, depending on the operating parameters of the particular well, 69.0 MPa. Disc burst values as high as ( 10,000 psi ) may be employed. Furthermore, the diameter of the opening of the instrument 94 that is opened when the disc 96 is ruptured may vary depending on the desired speed at which the cutting cylinder unit 36 is directed toward the plug 40. If a very high pressure difference has to be adjusted between the internal passage 38 of the tubular assembly 28 and the surrounding annulus, the cutting cylinder unit 36 is prevented from moving towards the plug 40 at an excessively high moving speed. The diameter of the hole through the instrument 94 may be selected to ensure that the flow rate of pressurized fluid into the chamber 84 is controlled.

  The leading edge segment 42a of the edge 42 of the cutting cylinder unit 36 initiates a continuous segmentation of the central segment 46 (illustrated by the dotted line 46a in FIG. 8) of the plug 40 from the peripheral portion 50 of the plug 40. It is moved into contact with the surface 52 of the body 44 of the plug. As can be seen from FIGS. 2, 5, and 10, the surface 52 of the plug 40 is provided with a long cavity 98 in the peripheral portion 50 of the plug 40 opposite the hinge structure 56. The cavity 98 is curved in its longitudinal direction and is placed in place inside the edge 54 in the region of the plug 40 where the leading edge segment 42a of the cutting cylinder 36 first contacts. The cavity 98 has a central region 100 that is deeper than the regions 102 and 104 on either side thereof. Part 58 preferably includes at least three integral projections 58a, b, and c that extend outwardly from the outermost circumferential edge of part 58. The interval between the projections 58a and 58b is narrower than the interval from the projection 58b to the projection 58c. Thus, the protrusions 58a-c are complementarily accommodated in the respective recesses 58d for the protrusions in the sub 34 (FIG. 9), and the leading edge segment 42a of the cutting cylinder unit 36 is centered in the cavity 98 of the plug 40. The plug 40 is securely arranged with respect to the sub 34 in an orientation that directly matches the region 100. Projections 58a, b, and c prevent plug 40 from rotating from a predetermined determined orientation relative to leading edge segment 42a of cutting cylinder 36 when housing 32 is attached to sub 34. Of sufficient size, shape and mass.

  While the cutting cylinder unit 36 is moved over a distance that divides the entire central segment 46 of the plug 40 due to the fluid pressure applied to the shoulder 90 of the piston projection 82, the cavity 98 of the plug 40 causes the leading edge segment 42a. The deformation force initially applied to the surface 52 of the plug 40 is reliably concentrated in a specific area of the plug 40. This specific region is a region that is narrower and thinner in cross section than the remainder of the peripheral portion 50. The leading edge 42 a of the edge 42 of the cutting cylinder unit 36 first contacts the plug 40 in the central region 100 of the cavity 98. In this way, the effective force applied to the plug 40 by the cutting cylinder unit 36 is concentrated directly on a specific area of the plug 40 that ensures the start of cutting of the plug 40.

  When the central segment 46 is completely separated from the peripheral portion 50 of the plug 40 by the tapered edge 42 of the cutting cylinder 36, the columnar outermost end 36b of the cutting cylinder unit 36 is then moved downward, thereby As shown in FIGS. 6 and 7, the segmented central segment 46 bends outward relative to its position. The side wall of the sub 34 has a cavity 108 arranged to accommodate the bent central segment 46 of the plug 40 and the portion of the hinge structure 56.

  As is most apparent from FIGS. 3, 6, and 7, when the central segment 46 is severed from the peripheral portion 50 of the plug 40 by the cutting cylinder unit 36, the U-shaped section 62 of the hinge structure 56 extends, thereby Not only is the segmented central segment 46 bent laterally, but the entire central segment can be moved independently of the peripheral portion 50 of the plug 40 and away from the peripheral portion. . The cutout 89 in the lowermost end 36b of the cutting cylinder unit 36 passes safely through the section 62 of the hinge structure 56 when the cutting cylinder unit 36 divides and bends the central section 46 of the plug 40. The cutting cylinder unit 36 causes the central segment 46 of the plug 40 to move axially and bend completely, thereby ensuring that the divided central section 46 of the plug 40 is completely moved into the cavity 108, so that The central section 46 does not interfere with the drift aperture of the tubular assembly 28. The leg portion 88b of the tab 88 is a leg portion when the leg portion 88b moves laterally in the space between the section 36c having the thin wall thickness of the cutting cylinder unit 36 and the innermost surface of the housing 32. The portion 88a is extended in a substantially parallel relationship. The cutting cylinder unit 36 is separated over the distance that the central section 46 of the plug 40 is cut by the leading edge of the cutting cylinder unit 36 by the continuous engagement of the side ends of the leg portions 88a and the opposing faces of the cavity 89. When the cylinder moves, the cutting cylinder unit 36 is prevented from rotating.

The cavity 98 of the plug 40 functions to advance the cutting of the plug 40 at a position where the mechanical load is maximized without adversely affecting the overall plug pressure rating. The range of movement of the entire split section 46 of the plug 40 in the axial direction of the passageway 38 of the tubular assembly 28 can be adjusted as needed by increasing or decreasing the length of the leg portions 66 and 68 of the U-shaped section 62 of the hinge structure 56. It may be changed.

  The lower portion 112 of the end portion 106 of the cutting cylinder unit 36 is machined to a smaller diameter than the upper portion of the unit 36 to provide a gap in the end portion 106 as the cutting cylinder 36 moves over the plug cutting distance. The longitudinally extending cut-away section 36c of the end 106 on the same side as the cutout 89 is also split when the split central section 46 of the plug 40 is bent into the cavity 108. Provide a gap for the surface 52 of the central section 46.

  The oil well finishing tool 120 of FIG. 13 differs from the tool 20 in that an instrument 194 with a rupturable site, such as a rupturable disk 196, is attached to the sidewall structure 180 of the tubular assembly 128. Further, as shown in FIG. 13, the cutting cylinder unit 136 may be composed of an assembly including a piston 122 and a cutting cylinder 124. In this example, the tubing string connected to the main passage 138 through the tubular assembly 128 is essentially at atmospheric pressure, as is the chamber 186 that receives the tip of the piston 122. A fluid pressure is applied downward to an annulus between a well casing, such as casing 26 of FIG. 1, and the outer surface of tubular assembly 128 to rupture disc 196 between the annulus and the internal passage of tubular assembly 128. The pressure introduced into the piston chamber 184 acting against the piston shoulder 190 of the piston projection 182 causes the pressure differential to be generated in a manner similar to that described with respect to the operation of the tubular assembly 28. The cutting cylinder assembly 136 is moved over the plug cutting distance.

  The oil well finishing tool 220 of FIG. 14 is in this example except that the tubing string and the main passage 238 of the tubular assembly 228 connected thereto are under a predetermined fluid pressure equal to the weight of the liquid in the tubing string. Is structurally the same as the tool 120. To actuate the cutting cylinder unit 236, sufficient fluid pressure is applied to the annulus around the tubular assembly 228 to rupture the disk 296 of the instrument 294 in the sidewall structure 288 of the tubular assembly 228. When the disk 296 ruptures, the cutting cylinder unit 236 moves over the plug cut distance as described with respect to the tools 20 and 120 due to the fluid pressure on the shoulder 290 of the piston projection 282.

  The oil well finishing tool 220 may optionally provide six 0.25 inch diameter holes 298 at 60 ° intervals around the piston, for example in a cutting cylinder piston unit 236. The purpose of the hole 298 is to provide a pressure higher than the normal annulus pressure of the well without exerting destructive forces on the tool housing 232, in particular the side wall structure 288 formed surrounding the part of the atmospheric pressure chamber 286 and the piston 236. To compensate. To actuate the tool 220, increasing the annulus pressure in the casing surrounding the tool 220 to a value greater than the pressure in the tubing string and the main passage 238 of the tubular assembly 228 causes the disk 296 to rupture and the piston 236 to rupture. Moves so as to divide from the plug 240.

  The oil well finishing tool 320 of FIG. 16 is the same as the tool 20 except that the plug 330 actuated by Kobe's drop bar has been replaced with a rupture disc portion 94 of the tool 20. Thus, when a conventional drop bar falls in a tubing string connected to the upper sub 376 of the tubular assembly 328, the tubular protrusion 332 of the Kobe plug is broken, thereby adding to the main passage 338 of the tubular assembly 328. A pressurized fluid is directed into the chamber 384. When pressurized fluid introduced into the chamber 384 flows into the piston shoulder 390 of the piston projection 382 of the cutting cylinder unit 336, the assembly corresponds to the atmospheric pressure chamber 341 as described above with respect to the tools 20, 120, and 220. Move over the plug cutting distance.

  The oil well finishing tool 420 of FIG. 17 is the same as the tool 20 except that a series of openings 426 are provided in the side wall structure 480 of the housing 432. Again, as before, six holes 426 with a diameter of 0.25 inches are preferably provided around the sidewall structure 480 at 60 degree intervals. In this example, chamber 486 is not at atmospheric pressure but at a pressure equal to the pressure of the fluid in the annulus between the tubular assembly 428 and the surrounding well casing. Thus, the fluid pressure in the main passage 438 of the tubular assembly 428 is increased to a level sufficient to cause the pressure differential to rupture the disk 496 compared to the pressure of the fluid in the annulus surrounding the tubular assembly 428 and in the chamber 486. Thus, the cutting cylinder unit 436 moves over a distance that divides the plug 440 by the fluid introduced into the chamber 486 acting on the piston shoulder 490 of the piston protrusion 482. The fluid pressure in the chamber 486 is equal to the pressure of the annulus surrounding the tubular assembly 428 due to the installation of the hole 426 so that when the cutting cylinder unit 436 moves with the pressure in the main passage 438 increased, the fluid in the chamber 486 Through the hole 426 and into the annulus space around the tubular assembly 428.

  The structure of the oil well finishing tool 420 with a series of holes 426 in the side wall of the housing 432 is particularly useful for changing well conditions, such as the very high pressure that can occur in very deep wells. In such a high pressure state, it may be necessary to operate the well finishing tool 420 using a pressure differential. The pressure difference is defined in this example as the difference between the pressure in the annulus and the pressure in the tubing string 22. The pressure difference may arise from the structure or geometry of the well and may be generated by pressurizing tubing or annulus from the ground surface.

  In an excessively high pressure well, the housing 432 may collapse or the piston wall 436 may burst in the direction of the atmospheric pressure chamber 486 due to the difference between the well pressure and the atmospheric pressure chamber 486. Since it is clear how much pressure is required to operate the finishing tool 420, it is possible to pressurize from the ground surface to the tubing string 22 at a pressure higher than the annulus pressure in order to operate the tool 420 properly. it can.

Claims (25)

An oil well finishing tool connected to a tubing string comprising a plurality of sections within an oil well casing,
A tubular assembly having a wall structure defining an elongated main passage extending in the axial direction and at least one of the ends connected to a section of the tubing string;
A severable plug attached to the tubular assembly so as to be normally in a blocking relationship with the axial passage;
A plug cutting edge provided in the passage of the assembly and normally spaced from the peripheral portion of the plug, the edge comprising the entire central segment of the plug and the remaining peripheral portion of the plug A movable cutting cylinder unit movable over the plug cutting distance to be cut from
Provided in the assembly and connected to the central segment of the plug, the entire central segment of the plug moving independently of the peripheral portion of the plug and away from the peripheral portion. An oil well finishing tool having an independent long hinge structure that is operable and operable to retain the segmented central segment of the plug in the main passage of the assembly.   The oil well finishing tool according to claim 1, wherein the hinge structure is configured to extend when the central segment of the plug is cut from the peripheral portion of the plug.   The oil well finishing tool according to claim 1, wherein the hinge structure is connected to the peripheral portion of the plug.   The wall structure includes a recess for receiving the split central segment of the plug, thereby preventing the split central segment of the plug from obstructing the main passage through the assembly. The oil well finishing tool according to claim 1.   The cutting cylinder unit has a tubular piston and a columnar plug cutting instrument, the piston being arranged such that the cutting instrument of the cutting cylinder can be moved toward the plug. The oil well finishing tool according to claim 1 attached to the passage.   The oil well of claim 1, wherein the peripheral portion of the plug is provided with an edge, and the wall structure of the assembly includes a circumferentially extending shoulder that is engageable with the edge of the plug. Finishing tool.   The oil well finishing tool according to claim 1, wherein a circular portion of the central segment of the plug is thicker than an annular peripheral portion of the plug.   The wall structure and the cutting cylinder unit include a piston shoulder facing the plug cutting edge of the cutting cylinder unit and a working fluid in the chamber so that the cutting cylinder unit moves over a cutting distance of the central segment. The oil well finishing tool according to claim 1, wherein the chamber is jointly formed with an actuating means allowing flow into the piston shoulder.   A rupturable portion is provided in the wall structure of the assembly, the rupturable portion being operable to apply a fluid pressure to the piston to move the piston, The oil well finishing tool according to claim 5, wherein the cutting tool of the cutting cylinder moves over a dividing distance of the central segment.   2. The central segment of the plug is provided with a cavity in the vicinity of the peripheral portion of the plug for initiating the division of the central segment of the plug by the edge of the cutting cylinder. Oil well finishing tool.   The oil well finishing tool according to claim 10, wherein the cavity is disposed on an opposite side of a connection region between the hinge structure and the assembly.   The oil well finishing tool according to claim 11, wherein the cavity includes a space deeper than a depth of a remaining part of the cavity.   The oil well finishing tool according to claim 12, wherein the cavity has a shallow portion on both sides of the space.   The oil well finishing tool according to claim 10, wherein the cavity has an elongated shape, and a specific space of the cavity is deeper than a remainder of the cavity, and the specific space is located in the middle of both ends of the cavity.   The oil well finishing tool according to claim 10, wherein the cavity is on the opposite side of the hinge structure of the central segment of the plug. The oil well finishing tool according to claim 10 , wherein the cavity is disposed inside and adjacent to the edge.   2. The oil well according to claim 1, wherein the plug dividing edge of the cutting cylinder unit is tapered, and has a leading edge segment and a trailing edge segment extending at a specific angle in a direction opposite to the leading edge segment. Finishing tool.   The well finishing tool according to claim 17, wherein each of the trailing edge segments extends at an angle of about 7 ° to about 18 ° with respect to a longitudinal axis of the passage.   The central segment of the plug is provided with a cavity adjacent to the peripheral portion of the plug, and the leading edge segment of the cutting cylinder unit is divided by the leading edge segment of the central segment of the plug. The oil well finishing tool according to claim 17, wherein the oil well finishing tool is substantially coincident with the position of the cavity to start the process in the cavity.   The oil well finishing tool according to claim 17, wherein the leading edge segment and the trailing edge segment are chamfered.   20. The oil well finishing tool according to claim 19, wherein the leading edge segment and the trailing edge segment are chamfered at an angle of about 15 degrees.   The hinge structure includes an annular part attached to the peripheral portion of the plug, and a substantially L-shaped long portion having a substantially U-shaped leg portion and an outer leg portion, and the U-shaped leg portion includes: Defined by an interconnected leg portion of one leg portion coupled to the annular part and the other leg portion coupled to the outer leg portion, the outer leg portion being connected to the central segment of the plug. The oil well finishing tool according to claim 1 to be attached.   The U-shaped leg portion of the hinge structure is formed such that the central segment of the plug is at least partially straight when separated from the peripheral portion of the plug, thereby 23. An oil well finishing tool according to claim 22, which allows the entire central segment to move independently of the peripheral portion of the plug and away from the peripheral portion.   9. The oil well finishing tool according to claim 8, wherein the actuating means has an actuating device extending to the main passage and interlocked by a drop rod to actuate the actuating means. An oil well finishing tool connected to a tubing string comprising a plurality of sections within an oil well casing,
A tubular assembly having a wall structure defining an elongated main passage extending in the axial direction and at least one of the ends connected to a section of the tubing string;
A severable plug attached to the tubular assembly so as to be normally in a blocking relationship with the axial passage;
A movable cutting cylinder unit with a plug cutting edge provided in the passage of the assembly and normally spaced apart from a peripheral portion of the plug;
The plug cutting edge of the cutting cylinder unit is tapered, and has a leading edge segment and a trailing edge segment extending at a specific angle in a direction opposite to the leading edge segment;
Wherein the central segment in the plug, adjacent the periphery of said plug and positioned approximately cavity that matches the leading edge segment of the cutting cylinder unit is provided,
The cutting cylinder unit is movable over a plug dividing distance, the leading edge segment starts dividing the central segment of the plug, and the leading edge segment and the trailing edge segment of the cutting cylinder unit An oil well finishing tool that jointly cuts the entire central segment of the plug from the remaining peripheral portion of the plug.

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