CN110454130B - Hydraulic jet infinite-stage fracturing device and fracturing method - Google Patents

Abstract

The application discloses unlimited level fracturing unit of hydraulic jet and fracturing method, this fracturing unit includes: the nozzle is arranged on the side wall of the cylindrical body and can communicate the inner cavity with the outside; the sliding sleeve is sleeved in the body and provided with a first position for closing the nozzle and a second position for opening the nozzle, and the sliding sleeve can axially slide along the inner wall of the body to be switched from the first position to the second position; the ball seat is sleeved in the body and fixedly connected with the sliding sleeve; the reducing ball is arranged in the ball seat and is provided with a first channel and a second channel, and the radius of the first channel is smaller than that of the second channel; the variable diameter ball has a first state and a second state which can be blocked by the sealing element; when the sliding sleeve switches the position, the variable diameter balls of the adjacent fracturing devices are switched from the first state to the second state. The fracturing device and the fracturing method can realize infinite-stage fracturing, the fracturing device is simple in structure and convenient to operate, can realize one-time tubular column operation and fixed-point fracturing, and are high in fracturing operation efficiency.

Description

Hydraulic jet infinite-stage fracturing device and fracturing method

Technical Field

The application relates to the technical field of oil and gas field fracturing, in particular to a hydraulic jet infinite-stage fracturing device and a hydraulic jet infinite-stage fracturing method.

Background

With the rapid development of economy, the development of conventional natural gas resources has not been able to meet the needs of economic development. Unconventional natural gas resources become the object of exploitation due to the characteristics of huge reserves, centralized distribution, gradual progress of development technology and the like. The realization of the industrialized exploitation of the unconventional natural gas has important significance for relieving the energy supply situation and guaranteeing the national energy safety.

Hydraulic fracturing technology is a necessary means to efficiently develop unconventional natural gas and maintain its economic exploitation. The hydraulic jet staged fracturing technology integrates hydraulic sand-blast perforating, fracturing and isolating, can realize fixed-point fracturing of a plurality of intervals by one string without mechanical packing, provides a feasible technical means for solving the problem that staged fracturing is difficult to realize by conventional packing, such as screen pipe/liner pipe well completion, casing change wells, poor well cementation quality and the like, can save perforating cost of new wells, and is one of the hot spots of yield increase modification research of oil and gas wells at home and abroad at present. However, the technology can only complete fracturing operation of limited stages and cannot meet the requirement of large-scale fracturing operation.

In order to develop unconventional natural gas efficiently, various distinctive infinite-stage segmental hydraulic fracturing systems are developed by foreign companies. The existing infinite staged hydraulic fracturing systems mainly comprise: multistage Unlimited fracturing systems, ZoneSelect Monobore fracturing systems, TAP fracturing systems, and OptiPort fracturing systems.

(1) Multistage Unlimited fracturing system

The Multistage Unlimited fracturing system is developed by NCS company, and is dragged by a continuous oil pipe and consists of a repeatable setting packer, a switchable fracturing sliding sleeve and a hydraulic sand blasting perforator, wherein the fracturing sliding sleeve is connected with the hydraulic sand blasting perforator, and the hydraulic sand blasting perforator is connected with the packer. But is not suitable for deeper formations due to coiled tubing operations. At the same time, infinite stages of fracturing using coiled tubing must be completed using casing. These problems all restrict the application and development of this technology.

(2) Zones Select Monobore fracturing system

The Zones ElectroMonoore fracturing system of Weatherford, Inc., consists essentially of: a sleeve sliding sleeve, a coiled tubing switch tool and the like. Utilize the coiled tubing to go into well sliding sleeve mounted position with supporting switching tool down, through the well head pump cycle of opening, the instrument produces throttle pressure differential, and switching tool locking piece exposes, cooperates and locks with the interior sliding sleeve circular bead, puts the tubular column through lifting and opens, closes the sliding sleeve. After the pump is stopped, the locking block is retracted, and the switching tool is separated from the inner sliding sleeve, so that the pipe string can be lifted out. However, the technology needs to intervene from the well completion stage, has complex process and long period, and is not suitable for the completed oil and gas wells.

(3) TAP fracturing system

The TAP fracturing system of Schlumberger company mainly comprises: the setting sub and ELEMENTAL on the pre-set casing string may dissolve the split ball seat 2 section. The split ball seat consists of 4 pieces, and the 4 pieces of ball seats are connected and supported through a special support frame and are connected with a setting tool. However, the system also has the problems that the TAP valve has strict requirements on the well inclination angle and the reservoir thickness and has higher requirements on the dissolution rate of the metal balls.

(4) OptiPort fracturing system

The OptiPort fracturing system of BJ company mainly comprises: casing slips and downhole combination tools (BHA). The sliding sleeve adopts a hydraulic opening mode, a hydraulic cylinder is formed between the shell and the body, and the inner sliding sleeve slides under the driving of hydraulic pressure to open the sliding sleeve. The BHA mainly comprises a coupling positioner, a throttling valve, an anchoring device and a packer, and can realize the positioning and anchoring of a fracturing string and the annular packing of the string and a casing. However, the system also has the problems of intervention, mechanical isolation and the like in the well completion stage.

In conclusion, the existing infinite-grade fracturing tool generally has the problems of complex structure, need of pulling out and running off the pipe column for multiple times and poor universality.

Disclosure of Invention

In view of the defects of the prior art, one of the purposes of the application is to provide the hydraulic jet infinite-stage fracturing device and the hydraulic jet infinite-stage fracturing method, the infinite-stage fracturing can be realized, the fracturing device is simple in structure and convenient to operate, mechanical packing is not needed, one-time tubular column operation and fixed-point fracturing can be realized, perforating, fracturing and isolation are integrated, and the fracturing operation efficiency is high.

In order to achieve the purpose, the technical scheme is as follows:

a hydrajetting infinite stage fracturing device comprising:

the nozzle is arranged on the side wall of the body and can communicate the inner cavity of the body with the outside of the body;

the sliding sleeve is sleeved in the body and provided with a first position enabling the nozzle to be closed and a second position enabling the nozzle to be opened, and the sliding sleeve can axially slide along the inner wall of the body to be switched from the first position to the second position;

the ball seat is sleeved in the body and fixedly connected with the sliding sleeve;

the reducing ball is arranged in the ball seat and is provided with a first channel and a second channel, and the radius of the first channel is smaller than that of the second channel; the reducing ball is provided with a first state that the second channel is axially communicated with the body and a second state that the first channel is axially communicated with the body, and the reducing ball can be blocked by a sealing element when in the second state; when the sliding sleeve is switched from the first position to the second position, the variable diameter balls of the adjacent fracturing devices can be switched from the first state to the second state.

As a preferred embodiment, the reducing ball is provided with a reducing portion, and the reducing portion includes:

the reducing rods are arranged at the two radial ends of the reducing ball, and the reducing rods rotate around the axis of the reducing rods to switch the reducing ball from the first state to the second state;

the diameter-changing block is arranged at one end of the diameter-changing rod, which is far away from the diameter-changing ball, and the diameter-changing block can drive the diameter-changing rod to rotate under the action of gravity so as to enable the diameter-changing ball to be switched from the first state to the second state; the outer wall of the body is provided with a first accommodating groove for accommodating the reducing block;

locate the stopper in the first holding tank, the stopper stops the reducing piece removes, makes the reducing ball keeps the first state.

In a preferred embodiment, the ball seat comprises a first ball seat and a second ball seat connected with each other; the first ball seat and the second ball seat are arranged in a hollow mode; the first ball seat with the sliding sleeve links to each other, first ball seat inner wall is kept away from the one end of sliding sleeve is the hemisphere, the second ball seat inner wall is close to the one end of sliding sleeve is the hemisphere, the hemisphere diameter with reducing ball external diameter equals.

As a preferred embodiment, the fracturing device further comprises a driving piece at least partially located outside the body, and the driving piece can connect the first ball seat and the limiting block of the adjacent fracturing device; the outer wall of the body is provided with a second accommodating groove for accommodating the driving piece;

the stopper is equipped with and is used for the installation the first installation department of driving the piece, first ball seat is close to the one end of sliding sleeve is equipped with and is used for the installation the second installation department of driving the piece.

As a preferred embodiment, the first channel and the second channel are perpendicular to each other, and the rotation angle of the reducing rod and the reducing block is 90 °;

the one end that first ball seat kept away from the sliding sleeve is equipped with and is used for the accommodate part the first breach of reducing pole, the second ball seat is close to the one end of sliding sleeve is equipped with and is used for the accommodate part the second breach of reducing pole.

As a preferred embodiment, the inner wall of the body is provided with a first step part and a second step part, one end of the sliding sleeve, which is far away from the ball seat, can be abutted against the first step part, and one end of the ball seat, which is close to the sliding sleeve, can be abutted against the second step part;

the outer diameter of the ball seat is larger than that of the sliding sleeve, the diameter of the second channel is equal to that of the sliding sleeve, and the minimum diameter of the first step part is smaller than that of the second step part.

As a preferred embodiment, a shear pin fixedly connected with the body is arranged on the side wall of the sliding sleeve and the ball seat along the circumferential direction; a first sealing ring is arranged between the outer wall of the sliding sleeve and the inner wall of the body, and a second sealing ring is arranged between the outer wall of the ball seat and the inner wall of the body; the side wall of the body is provided with a nozzle mounting hole used for sealing the nozzle and a pin mounting hole used for arranging the shearing pin.

As a preferred embodiment, one end of the sealing element is a solid cone, and the solid cone can block the reducing ball in the second state.

As a preferred embodiment, the hydraulic jet infinite stage fracturing device further comprises a joint for connecting adjacent fracturing devices, wherein the joint is hollow cylindrical, and one end of the joint can limit the ball seat.

A fracturing method based on the hydraulic jet infinite stage fracturing device of any one of the above embodiments, comprising the following steps:

step a: the multi-stage fracturing devices and the oil pipe are connected in series, the reducing ball of the first-stage fracturing device is in a second state that the first channel is axially communicated with the body, the sealing element is thrown into the first-stage fracturing device, and the ball seat of each stage of fracturing device is connected with the reducing ball of the next-stage fracturing device;

step b: the assembled oil pipe and the connected multistage hydraulic jet infinite stage fracturing device are put into a casing of a stratum needing hydraulic jet fracturing;

step c: pumping high-pressure fluid into the oil pipe from the ground, wherein the sealing element is abutted against a first channel of the fracturing device under the action of the fluid pressure;

step d: increasing the ground discharge capacity to enable the sliding sleeve to be separated from the first position, sliding downwards to the second position along the axial direction, opening the nozzle, and enabling high-pressure fluid to form high-speed jet flow through the nozzle; simultaneously driving the reducing ball of the next stage of fracturing device to switch the reducing ball of the next stage of fracturing device from a first state to a second state;

step e: starting the hydraulic jet fracturing operation: firstly, pumping perforating fluid, performing casing windowing operation, then pumping fracturing fluid, simultaneously controlling the annular pressure to be close to the formation fracture pressure, forming pressurization in the formation by high-pressure jet flow, and compounding the annular pressure to realize formation fracture initiation to finish jet fracturing;

step f: after the hydraulic jet fracturing operation of the stage is finished, a sealing element is put in, and a reducing ball of the next stage of fracturing device is plugged by the sealing element;

step g: and (f) starting jet fracturing operation of the next-stage hydraulic jet infinite fracturing device, and repeating the steps from c to f to finish all hydraulic jet fracturing operations.

Has the advantages that:

1. the hydraulic jet infinite-stage fracturing device and the hydraulic jet infinite-stage fracturing method have the advantages that the sealing elements are thrown in and the fluid discharge capacity is controlled, so that the position switching of the sliding sleeve is realized, the nozzle is opened for infinite times, and infinite-stage fracturing is realized. When the hydraulic jet infinite-stage fracturing device is used, a structural form that the multistage fracturing device is connected on an oil pipe in series is adopted. The upper end of the first stage fracturing device (namely the fracturing device closest to the well bottom) is connected with the second stage fracturing device, and the upper end of the uppermost stage fracturing device (namely the fracturing device closest to the well top) is connected with the oil pipe to realize series connection. The reducing ball of the first-stage fracturing device is in a second state that the first channel is axially communicated with the body, so that the reducing ball can be blocked by the sealing element; the reducing balls of the rest stages of fracturing devices are in the first state that the second channel is communicated with the body in the axial direction, so that the sealing element can pass through smoothly. The sealing element of the first-stage fracturing device is thrown into the fracturing device, when the ground starts to pump fluid, the sealing element is set with the reducing ball of the first-stage fracturing device, the ground displacement is increased to increase the underground pressure, the sliding sleeve is separated from a fixed position (namely a first position) under the action of high pressure and slides downwards to a second position along the axial direction together with the ball seat, and the reducing ball of the second-stage fracturing device is switched from the first state to the second state when the nozzle is opened so as to be plugged by the sealing element. And high-pressure fluid enters the stratum through the nozzle to realize stratum fracture initiation and complete jet fracturing at the position. After fracturing is finished, the sealing element is thrown in again, the sealing element is limited after reaching the second-stage fracturing device, and the steps of pumping the fluid and increasing the discharge capacity are repeated at the moment, so that the fracturing of the stratum at the second-stage fracturing device can be realized. By analogy, the fracturing of multiple layers of a pipe column can be realized once, infinite hydraulic fracturing can be realized, the operation time can be shortened, the hydraulic fracturing efficiency can be improved, and the labor intensity of workers can be reduced.

2. The fracturing device is simple in structure. Under the complicated condition in the pit, simple structure can guarantee that fracturing unit has better reliability.

3. The fracturing device and the fracturing method are simple and convenient to operate and high in safety. And as the pipe column is not moved in the fracturing process, the safety factor is increased, and the construction operation is simple and convenient.

4. The fracturing method starts fracturing from a far well end, and ensures that fracturing is orderly developed in the multi-stage fracturing process.

Specific embodiments of the present application are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the application may be employed. It should be understood that the embodiments of the present application are not so limited in scope.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a schematic diagram of an internal structure of a hydrajetting infinite stage fracturing device provided in an embodiment of the present application;

FIG. 2 is a rear view of the fracturing apparatus of FIG. 1 prior to the reducing of the reducing ball;

FIG. 3 is a cross-sectional view taken along the line A-A in FIG. 2;

FIG. 4 is a rear view of the fracturing apparatus of FIG. 1 after the reducing ball has been reduced;

FIG. 5 is a cross-sectional view taken along line B-B of FIG. 4;

FIG. 6 is a schematic diagram of the external configuration of the first and second stages of the fracturing apparatus of FIG. 1 in tandem;

FIG. 7 is an enlarged view of a portion of FIG. 6 at I;

FIG. 8 is a rear view of the first and second stages of the fracturing apparatus of FIG. 1 in tandem;

FIG. 9 is a cross-sectional view taken along plane C-C of FIG. 8;

FIG. 10 is a schematic structural diagram of a body according to an embodiment of the present disclosure;

FIG. 11 is a rear view of FIG. 10;

FIG. 12 is a cross-sectional view taken along plane D-D of FIG. 11;

FIG. 13 is a schematic structural view of a sliding sleeve according to an embodiment of the present disclosure;

FIG. 14 is a rear view of FIG. 13;

FIG. 15 is a cross-sectional view taken along plane E-E of FIG. 14;

FIG. 16 is a schematic structural diagram of a reducing ball according to an embodiment of the present disclosure;

FIG. 17 is a rear view of FIG. 16;

FIG. 18 is a cross-sectional view taken along plane F-F of FIG. 17;

FIG. 19 is a schematic view of a first tee in accordance with an embodiment of the present disclosure;

FIG. 20 is a rear view of FIG. 19;

FIG. 21 is a cross-sectional view taken along plane G-G of FIG. 20;

FIG. 22 is a schematic view of a second ball holder according to an embodiment of the present disclosure;

FIG. 23 is a rear view of FIG. 22;

FIG. 24 is a cross-sectional view taken along plane H-H of FIG. 23;

FIG. 25 is a schematic structural view of a joint provided in an embodiment of the present application;

FIG. 26 is a schematic view of a seal provided in an embodiment of the present application;

fig. 27 is a flow chart illustrating steps of a hydrajetting infinite stage fracturing method provided in an embodiment of the present application.

Description of reference numerals:

1. a body; 11. a first step portion; 12. a second step portion; 13. a first accommodating groove; 2. a nozzle; 3. a sliding sleeve; 4. a variable diameter ball; 41. a first channel; 42. a second channel; 43. a reducer bar; 44. a diameter-variable block; 45. a limiting block; 5. a first ball seat; 51. a first notch; 52. a second mounting portion; 6. a second ball seat; 61. a second notch; 7. a driver; 8. a seal member; 81. a cone; 9. and (4) a joint.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

For convenience of description, the direction near the wellhead is defined as "up" and the direction near the bottom of the well is defined as "down". The fracturing device in this application embodiment can concatenate, forms by multistage the fracturing unit that the fracturing device is constituteed, and the progression of fracturing unit can set up as required. For convenience of explanation, the first stage fracturing device closest to the well bottom is defined as a "first stage fracturing device", the next stage fracturing device is arranged above each stage fracturing device, and the previous stage fracturing device is arranged below each stage fracturing device.

In order to meet the requirements of unconventional oil and gas resource development and overcome the defects of the prior art, the inventor provides the hydraulic jet infinite-stage fracturing device and the fracturing method according to the practice of carrying out hydraulic fracturing construction for many years and the experience of developing fracturing tools so as to overcome the defects of the prior art.

Please refer to fig. 1 to 5. The utility model provides a hydraulic jet infinite stage fracturing unit in the embodiment of this application, the device includes: the ball sealing device comprises a body 1, a sliding sleeve 3, a ball seat, a reducing ball 4 and a sealing element 8.

As shown in fig. 10 to 12, the body 1 extends in the axial direction and has a cylindrical shape. Adjacent fracturing units can be directly connected through the bodies 1, or a joint 9 as shown in fig. 25 can be arranged between the bodies 1 to realize connection. The connection mode can select threaded connection, and is more reliable and convenient, and certainly, other feasible connection modes can also be selected, for example, snap connection, and the embodiment of the application does not limit the connection modes.

The side wall of the body 1 is provided with a nozzle 2 which can communicate the inner cavity of the body 1 and the outside of the body 1. The side wall of the body 1 can also be provided with a nozzle 2 mounting hole for sealing the nozzle 2. The inner cavity of the body 1 can accommodate components such as a sliding sleeve 3, a ball seat, a sealing element 8 and the like, and can provide a flow passage for fluid pumped from the ground. When the nozzle 2 is opened, high-pressure fluid can be sprayed out from the nozzle 2 and enters the stratum to realize stratum fracture initiation and complete the jet fracturing at the position.

The nozzle 2 can be opened by an axial displacement of the sliding sleeve 3. Specifically, the sliding sleeve 3 is sleeved in the body 1 in a sealing manner. The sliding sleeve 3 has a first position in which the nozzle 2 is closed and a second position in which the nozzle 2 is open. The sliding sleeve 3 can slide axially along the inner wall of the body 1 to switch from the first position to the second position. When the sliding sleeve is applied to the underground, the axial moving direction of the sliding sleeve 3 is downward. The structure of the sliding sleeve 3 provided in the embodiment of the present application is shown in fig. 13 to 15.

In the embodiment of the application, the ball seat is sleeved in the body 1 and is fixedly connected with the sliding sleeve 3. When the sliding sleeve 3 slides axially, the ball seat can also slide axially along with the sliding sleeve 3. A reducing ball 4 is arranged in the ball seat, the reducing ball 4 is provided with a first channel 41 and a second channel 42, and the radius of the first channel 41 is smaller than that of the second channel 42. The first channel 41 can limit the sealing element 8, and the second channel 42 can enable the sealing element 8 to pass through smoothly. The reducing ball 4 has a first state in which the second passage 42 is axially communicated with the body 1, and a second state in which the first passage 41 is axially communicated with the body 1. The reducing ball 4 can be blocked by a sealing element 8 when in the second state. When the sliding sleeve 3 is switched from the first position to the second position, the variable diameter ball 4 of the adjacent fracturing device is switched from the first state to the second state.

Specifically, the reducing ball 4 is provided with a reducing portion for realizing reducing. The variable diameter is switched from the position where the second channel 42 is axially communicated with the body 1 to the position where the first channel 41 is axially communicated with the body 1, that is, the variable diameter ball 4 is switched from the first state to the second state. As shown in fig. 7 and 16 to 18, the reducing portion includes a reducing rod 43, a reducing block 44, and a stopper 45.

The reducing rods 43 are arranged at two ends of the reducing ball 4 in the radial direction. Namely, a reducing rod 43 is respectively arranged at the two radial ends of the reducing ball 4. The rotation of the reducing rod 43 about its axis switches the reducing ball 4 from the first state to the second state. The axial direction of the reducing rod 43 is the radial direction of the reducing ball 4.

And a reducing block 44 is arranged at one end of the reducing rod 43 far away from the reducing ball 4. The reducing block 44 can drive the reducing rod 43 to rotate under the action of gravity, so that the reducing ball 4 is switched from the first state to the second state. Specifically, the center of gravity of the reducing block 44 is located on one side of the axis of the reducing rod 43, that is, the center of gravity of the reducing block 44 and the axis of the reducing rod 43 are not located on the same straight line, so that the reducing block 44 can drive the reducing ball 4 to rotate under the action of gravity, and the first state is switched to the second state.

As shown in fig. 7, the outer wall of the body 1 is provided with a first receiving groove 13 for receiving the diameter-changing block 44. A limiting block 45 is further arranged in the first accommodating groove 13 and used for preventing the reducing block 44 from moving under the action of gravity, so that the reducing ball 4 is kept in the first state. The limiting block 45 does not exceed the outer wall surface of the body 1, so that the outer wall surface of the fracturing device is smooth, and the fracturing device can be smoothly put into a well without collision. The shape of the limiting block 45 is not limited in the embodiment of the present application. As shown in fig. 7, the stopper 45 may be a cylinder.

In the embodiment of the present application, as shown in fig. 16, the first passage 41 and the second passage 42 are perpendicular to each other, and the rotation angle of the diameter-changing rod 43 and the diameter-changing block 44 is 90 °. When the reducing ball 4 is in the first state, the sealing element 8 can smoothly pass through the reducing ball 4, the reducing block 44 is limited at a horizontal position by the limiting block 45, the center of gravity of the reducing block 44 is located on one side of a vertical plane where the connecting line of the center of the reducing ball 4 and the center of the reducing rod 43 is located, and the reducing block 44 and the reducing rod 43 are located on the same horizontal plane. When the reducing ball 4 is in the second state, the sealing element 8 is limited by the reducing ball 4, the reducing block 44 is not limited by the limiting block 45 and is located at a vertical position, the gravity center of the reducing block 44 is located in a vertical plane where the connecting line of the spherical center of the reducing ball 4 and the center of the reducing rod 43 is located, and the reducing block 44 is located below the reducing rod 43.

More specifically, the ball seat includes a first ball seat 5 and a second ball seat 6 connected, the first ball seat 5 being shown in fig. 19 to 21, and the second ball seat 6 being shown in fig. 22 to 24. The first and second ball seats 5 and 6 are hollow to provide a flow passage for fluid. The first ball seat 5 is connected with the sliding sleeve 3. One end of the inner wall of the first ball seat 5, which is far away from the sliding sleeve 3, is hemispherical so as to accommodate part of the reducing ball 4. One end of the inner wall of the second ball seat 6, which is close to the sliding sleeve 3, is hemispherical so as to accommodate the rest part of the reducing ball 4. The hemispherical diameter is equal to the outer diameter of the reducing ball 4. The first ball seat 5 is provided at a lower end thereof with a first gap 51 for receiving a portion of the reducer shaft 43. The second ball seat 6 is provided at an upper end thereof with a second notch 61 for receiving a portion of the reducer shaft 43.

In the present embodiment, the fracturing device also comprises a driver 7 located at least partially outside the body. The driving piece 7 can be adjacent to the fracturing device, the first ball seat 5 is connected with the limiting block 45, so that the downward sliding of the first ball seat 5 of the stage is driven by the downward sliding of the sliding sleeve 3 of the stage, the limiting block 45 of the next stage of fracturing device is pulled to be damaged, and the reducing ball of the next stage of fracturing device can be switched to the second state from the first state.

Specifically, a channel through which the driving member 7 passes is formed in the side wall of the body 1, and the driving member 7 passes through the first ball seat 5 (i.e., inside the body 1) to the outside of the body 1. Spacing the driver 7 from the fluid flow path enables more reliable transmission of the fracturing units at each stage while protecting the driver 7. The outer wall of the body 1 is provided with a second accommodating groove for accommodating the driving piece 7, so that the driving piece 7 is not protruded out of the outer wall surface of the body 1, the outer wall surface of the fracturing device is smooth, and the fracturing device can be smoothly and conveniently lowered into a well without collision. The limiting block 45 is provided with a first mounting portion for mounting the driving member 7, so that the limiting block 45 is connected with the driving member 7. One end of the first ball seat 5 close to the sliding sleeve 3 is provided with a second mounting part 52 for mounting the driving part 7.

In a specific embodiment, the driving member 7 may be a steel wire rope, so as to ensure reliable driving performance. One end of the steel wire rope is fixed by a second mounting part 52 on the first ball seat 5 of the fracturing device of the current stage, and the other end of the steel wire rope is fixed by a first mounting part on the limiting block 45 of the next stage of fracturing device.

In the embodiment of the present application, in order to limit the sliding sleeve 3 and the ball seat, the inner wall of the body 1 is provided with a first step portion 11 and a second step portion 12. The upper end of the sliding sleeve 3 can be abutted against the first step part 11. The upper end of the first ball seat 5 can be pressed against the second step part 12.

Specifically, the diameter of the second passage 42 is equal to the inner diameter of the sliding sleeve 3, so that the sealing element 8 can pass through the second passage more smoothly. In order to better accommodate the reducing ball 4, the outer diameter of the ball seat is larger than that of the sliding sleeve 3. So that the smallest diameter of the first step 11 is smaller than the smallest diameter of the second step 12.

In the embodiment of the present application, in order to fix the sliding sleeve 3 and the ball seat in the body 1, in addition to the above-mentioned first step portion 11 and the second step portion 12, a shear pin for fixedly connecting with the body 1 may be disposed along the circumferential direction on the side walls of the sliding sleeve 3 and the ball seat. The first and second seats 5, 6 may also be connected by shear pins. Be equipped with on the lateral wall of body 1 and be used for setting up the pin mounting hole of shear pin. A first sealing ring is arranged between the outer wall of the sliding sleeve 3 and the inner wall of the body 1, and a second sealing ring is arranged between the outer wall of the ball seat and the inner wall of the body 1.

In the embodiment of the present application, the connection mode of the respective members is as follows. The inner wall of the first ball seat 5 is provided with a thread part used for being connected with the lower end of the sliding sleeve 3. The lower extreme of sliding sleeve 3 is equipped with the external screw thread with screw thread portion matched with. The body 1 of the upper and lower stage fracturing devices may be threadedly connected by a fitting 9. The joint 9 is hollow cylindrical, one end of the joint 9 can limit the second ball seat 6, and further limit the sliding sleeve 3 after sliding.

Specifically, the first step 11 and the second step 12 limit the sliding sleeve 3 and the first ball seat 5 when the sliding sleeve 3 and the ball seat are fixed in the body 1. Once the shear pin of the sliding sleeve 3 and the reducer rod 43 of the fracturing device of the current stage are damaged, the sliding sleeve 3 and the ball seat slide downwards until the joints 9 of the fracturing device of the current stage are met and the sliding stops. The sliding sleeve 3 can drive the limiting block 45 which destroys the next stage of fracturing device when sliding downwards, so that the reducing ball 4 of the next stage can be changed in diameter, the first channel 41 and the body 1 are switched to the axial communication position, and the reducing ball 4 can be blocked by the sealing element 8 at the moment.

In the embodiment of the present application, as shown in fig. 26, the lower portion of the sealing element 8 is a solid cone 81, so as to have better sealing performance when contacting with the first channel 41, and the solid cone 81 can block the reducing ball 4 in the second state. The upper part of the sealing element 8 can be in a solid cylinder shape, the lower part of the sealing element is in a solid cone shape, and the outer diameter of the lower part does not exceed the outer diameter of the upper part.

The hydraulic jet infinite-stage fracturing device provided by the embodiment of the application realizes the position switching of the sliding sleeve 3 by throwing the sealing piece 8 and controlling the fluid discharge capacity so as to open the nozzle 2 for infinite times and realize infinite-stage fracturing.

When the hydraulic jet infinite-stage fracturing device is used, a structural form that the multistage fracturing device is connected on an oil pipe in series is adopted. The first stage fracturing device (i.e. the fracturing device closest to the well bottom) is positioned at the bottommost end, the upper end of the first stage fracturing device is connected with the second stage fracturing device, and the upper end of the topmost stage fracturing device (i.e. the fracturing device closest to the well top) is connected with an oil pipe to realize series connection. Fig. 6 to 9 are schematic structural diagrams of the first stage and the second stage fracturing devices connected in series.

The reducing ball 4 of the first-stage fracturing device is in a second state that the first channel 41 is axially communicated with the body 1, so that the reducing ball 4 can be blocked by the sealing element 8; the variable diameter balls 4 of the rest stages of fracturing devices are in a first state that the second channel 42 is communicated with the body 1 in the axial direction, so that the sealing element 8 can pass through smoothly.

The sealing element 8 of the first-stage fracturing device is thrown into the fracturing device, when the ground starts to pump fluid, the sealing element 8 is set with the reducing ball 4 of the first-stage fracturing device, the ground displacement is increased at the moment to increase the underground pressure, the sliding sleeve 3 is separated from a fixed position (namely a first position) under the action of high pressure, and slides downwards to a second position along the axial direction together with the ball seat, and the reducing ball 4 of the second-stage fracturing device is switched from the first state to the second state when the nozzle 2 is opened so as to be plugged by the sealing element 8. High-pressure fluid enters the stratum through the nozzle 2, so that the stratum is cracked, and jet fracturing at the position is completed.

After fracturing, throw into sealing member 8 again, by spacing after sealing member 8 reachs second stage fracturing device, repeat above-mentioned pumping fluid and increase the step of discharge capacity this moment, just can realize the fracturing of second stage fracturing device department stratum. By analogy, the fracturing of multiple layers of a pipe column can be realized once, infinite hydraulic fracturing can be realized, the operation time can be shortened, the hydraulic fracturing efficiency can be improved, and the labor intensity of workers can be reduced.

The fracturing device is simple in structure. Under the complicated condition in the pit, simple structure can guarantee that fracturing unit has better reliability. The fracturing device and the fracturing method are simple and convenient to operate and high in safety. And as the pipe column is not moved in the fracturing process, the safety factor is increased, and the construction operation is simple and convenient. The fracturing method starts fracturing from a far well end, and ensures that fracturing is orderly developed in the multi-stage fracturing process.

Referring to fig. 27, in the present embodiment, a corresponding hydraulic jet infinite stage fracturing method is further provided based on the hydraulic jet infinite stage fracturing device. Specifically, the fracturing method can comprise the following steps:

step a: the multi-stage fracturing devices and the oil pipe are connected in series, the reducing ball of the first-stage fracturing device is in a second state that the first channel is axially communicated with the body, the sealing element is thrown into the first-stage fracturing device, and the ball seat of each stage of fracturing device is connected with the reducing ball of the next-stage fracturing device;

step b: the assembled oil pipe and the connected multistage hydraulic jet infinite stage fracturing device are put into a casing of a stratum needing hydraulic jet fracturing;

step c: pumping high-pressure fluid into the oil pipe from the ground, wherein the sealing element is abutted against a first channel of the fracturing device under the action of the fluid pressure;

step d: increasing the ground discharge capacity to enable the sliding sleeve to be separated from the first position, sliding downwards to the second position along the axial direction, opening the nozzle, and enabling high-pressure fluid to form high-speed jet flow through the nozzle; simultaneously driving the reducing ball of the next stage of fracturing device to switch the reducing ball of the next stage of fracturing device from a first state to a second state;

step e: starting the hydraulic jet fracturing operation: firstly, pumping perforating fluid, performing casing windowing operation, then pumping fracturing fluid, simultaneously controlling the annular pressure to be close to the formation fracture pressure, forming pressurization in the formation by high-pressure jet flow, and compounding the annular pressure to realize formation fracture initiation to finish jet fracturing;

step f: after the hydraulic jet fracturing operation of the stage is finished, a sealing element is put in, and a reducing ball of the next stage of fracturing device is plugged by the sealing element;

step g: and (f) starting jet fracturing operation of the next-stage hydraulic jet infinite fracturing device, and repeating the steps from c to f to finish all hydraulic jet fracturing operations.

In the step a, the first stage fracturing device (i.e. the fracturing device closest to the well bottom) is the bottommost end, the upper end of the first stage fracturing device is connected with the second stage fracturing device, and the upper end of the topmost stage fracturing device (i.e. the fracturing device closest to the well top) is connected with the oil pipe to realize series connection. The reducing ball 4 of the first stage fracturing device is in a second state that the first channel 41 is communicated with the body 1 in the axial direction, so that the reducing ball 4 can be blocked by the sealing element 8. The variable diameter balls 4 of the rest stages of fracturing devices are in a first state that the second channel 42 is communicated with the body 1 in the axial direction, so that the sealing element 8 can pass through smoothly. The seal 8 of the first stage of the fracturing unit is thrown into the fracturing unit.

In step c, the high-pressure fluid is pure fluid which is commonly used in the perforation preparation stage, and the upper limit of the pressure range of the high-pressure fluid is the pressure reaching the casing windowing.

In the step d, the ground displacement is increased instantaneously to increase the pressure of the oil pipe, under the action of high pressure, the axial force borne by the sliding sleeve 3 is greater than the allowable shearing force of the shearing pin, the shearing pin is sheared, the combined body consisting of the sliding sleeve 3, the ball seat, the sealing element 8 and the driving element 7 moves downwards rapidly, the nozzle 2 on the side wall of the body 1 is opened, high-pressure fluid forms high-speed jet flow through the nozzle 2, the driving element 7 pulls and destroys the limiting block 45 of the second-stage fracturing device, and the reducing ball 4 of the second-stage fracturing device is switched from the first state to the second state and can be blocked by the sealing element 8.

In the step e, the perforating fluid is a mixed liquid and is formed by mixing abrasive materials in the liquid, and the perforating fluid is uniformly mixed by a ground pump truck and then pumped into an oil pipe. The fracturing fluid is generally a pure liquid. The completion of the jet fracturing job may be determined by monitoring casing pressure.

In this embodiment, the method embodiment corresponds to the apparatus embodiment, which can achieve the technical problems solved by the apparatus embodiment, and accordingly achieve the technical effects of the apparatus embodiment, and detailed descriptions of this application are omitted here.

It is noted that the hydraulically-jetted infinite stage fracturing method can be implemented using, but not limited to, the hydraulically-jetted infinite stage fracturing apparatus of any of the embodiments or examples described above, and it is understood that any changes made without departing from the spirit provided by the hydraulically-jetted infinite stage fracturing method are within the scope of the present application.

It should be noted that, in the description of the present application, the terms "first", "second", and the like are used for descriptive purposes only and for distinguishing similar objects, and no precedence between the two is intended or should be construed to indicate or imply relative importance. In addition, in the description of the present application, "a plurality" means two or more unless otherwise specified.

All articles and references disclosed, including patent applications and publications, are hereby incorporated by reference for all purposes. The term "consisting essentially of …" describing a combination shall include the identified element, ingredient, component or step as well as other elements, ingredients, components or steps that do not materially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, components, or steps herein also contemplates embodiments that consist essentially of such elements, components, or steps. By using the term "may" herein, it is intended to indicate that any of the described attributes that "may" include are optional.

A plurality of elements, components, parts or steps can be provided by a single integrated element, component, part or step. Alternatively, a single integrated element, component, part or step may be divided into separate plural elements, components, parts or steps. The disclosure of "a" or "an" to describe an element, ingredient, component or step is not intended to foreclose other elements, ingredients, components or steps.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many embodiments and many applications other than the examples provided will be apparent to those of skill in the art upon reading the above description. The disclosures of all articles and references, including patent applications and publications, are hereby incorporated by reference for all purposes.

Claims (10)

1. A hydrajetting infinite stage fracturing device, comprising:

the nozzle is arranged on the side wall of the body and can communicate the inner cavity of the body with the outside of the body;

the sliding sleeve is sleeved in the body and provided with a first position enabling the nozzle to be closed and a second position enabling the nozzle to be opened, and the sliding sleeve can axially slide along the inner wall of the body to be switched from the first position to the second position;

the ball seat is sleeved in the body and fixedly connected with the sliding sleeve;

the reducing ball is arranged in the ball seat and is provided with a first channel and a second channel, and the radius of the first channel is smaller than that of the second channel; the reducing ball is provided with a first state that the second channel is axially communicated with the body and a second state that the first channel is axially communicated with the body, and the reducing ball can be blocked by a sealing element when in the second state; when the sliding sleeve is switched from the first position to the second position, the variable diameter balls of the adjacent fracturing devices can be switched from the first state to the second state.

2. The hydrajetting infinite stage fracturing device of claim 1, wherein the reducing ball is provided with a reducing portion, the reducing portion comprising:

the reducing rods are arranged at the two radial ends of the reducing ball, and the reducing rods rotate around the axis of the reducing rods to switch the reducing ball from the first state to the second state;

the diameter-changing block is arranged at one end of the diameter-changing rod, which is far away from the diameter-changing ball, and the diameter-changing block can drive the diameter-changing rod to rotate under the action of gravity so as to enable the diameter-changing ball to be switched from the first state to the second state; the outer wall of the body is provided with a first accommodating groove for accommodating the reducing block;

locate the stopper in the first holding tank, the stopper stops the reducing piece removes, makes the reducing ball keeps the first state.

3. The hydrajetting infinite stage fracturing device of claim 2, wherein the ball seat comprises a first ball seat and a second ball seat connected; the first ball seat and the second ball seat are arranged in a hollow mode; the first ball seat with the sliding sleeve links to each other, first ball seat inner wall is kept away from the one end of sliding sleeve is the hemisphere, the second ball seat inner wall is close to the one end of sliding sleeve is the hemisphere, the hemispherical diameter of first ball seat and second ball seat all with reducing ball external diameter equals.

4. The hydrajetting infinite stage fracturing device of claim 3, further comprising a driver at least partially external to the body, the driver capable of connecting the first ball seat and a stop block adjacent the fracturing device; the outer wall of the body is provided with a second accommodating groove for accommodating the driving piece;

the stopper is equipped with and is used for the installation the first installation department of driving the piece, first ball seat is close to the one end of sliding sleeve is equipped with and is used for the installation the second installation department of driving the piece.

5. The hydrajetting infinite stage fracturing device of claim 3, wherein the first channel and the second channel are perpendicular to each other, and the rotation angle of the reducer rod and the reducer block is 90 °;

the one end that first ball seat kept away from the sliding sleeve is equipped with and is used for the accommodate part the first breach of reducing pole, the second ball seat is close to the one end of sliding sleeve is equipped with and is used for the accommodate part the second breach of reducing pole.

6. The hydraulic jet infinite stage fracturing device of claim 1, wherein the inner wall of the body is provided with a first step part and a second step part, one end of the sliding sleeve, which is far away from the ball seat, can abut against the first step part, and one end of the ball seat, which is close to the sliding sleeve, can abut against the second step part;

the outer diameter of the ball seat is larger than that of the sliding sleeve, the diameter of the second channel is equal to that of the sliding sleeve, and the minimum diameter of the first step part is smaller than that of the second step part.

7. The hydrajetting infinite stage fracturing device of claim 1, wherein shear pins for fixedly connecting with the body are arranged on the side walls of the sliding sleeve and the ball seat along the circumferential direction; a first sealing ring is arranged between the outer wall of the sliding sleeve and the inner wall of the body, and a second sealing ring is arranged between the outer wall of the ball seat and the inner wall of the body; the side wall of the body is provided with a nozzle mounting hole used for sealing the nozzle and a pin mounting hole used for arranging the shearing pin.

8. The hydrajetting infinite stage fracturing device of claim 1, wherein one end of the seal is a solid cone that can block the reducing ball in the second state.

9. The hydrajetting infinite stage fracturing device of claim 1, further comprising a joint for connecting adjacent ones of the fracturing devices, the joint being hollow cylindrical, one end of the joint being capable of retaining the ball seat.

10. A fracturing method based on the hydrajetting infinite stage fracturing device of any one of claims 1 to 9, characterized by comprising the following steps:

step a: the multi-stage fracturing devices and the oil pipe are connected in series, the reducing ball of the first-stage fracturing device is in a second state that the first channel is axially communicated with the body, the sealing element is thrown into the first-stage fracturing device, and the ball seat of each stage of fracturing device is connected with the reducing ball of the next-stage fracturing device;

step b: the assembled oil pipe and the connected multistage hydraulic jet infinite stage fracturing device are put into a casing of a stratum needing hydraulic jet fracturing;

step c: pumping high-pressure fluid into the oil pipe from the ground, wherein the sealing element is abutted against a first channel of the fracturing device under the action of the fluid pressure;

step d: increasing the ground discharge capacity to enable the sliding sleeve to be separated from the first position, sliding downwards to the second position along the axial direction, opening the nozzle, and enabling high-pressure fluid to form high-speed jet flow through the nozzle; simultaneously driving the reducing ball of the next stage of fracturing device to switch the reducing ball of the next stage of fracturing device from a first state to a second state;

step e: starting the hydraulic jet fracturing operation: firstly, pumping perforating fluid, performing casing windowing operation, then pumping fracturing fluid, simultaneously controlling the annular pressure to be close to the formation fracture pressure, forming pressurization in the formation by high-pressure jet flow, and compounding the annular pressure to realize formation fracture initiation to finish jet fracturing;

step f: after the hydraulic jet fracturing operation of the stage is finished, a sealing element is put in, and a reducing ball of the next stage of fracturing device is plugged by the sealing element;

step g: and (f) starting jet fracturing operation of the next-stage hydraulic jet infinite fracturing device, and repeating the steps from c to f to finish all hydraulic jet fracturing operations.

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