Full bore unlimited stage fracturing sliding sleeve for horizontal well

Abstract

The present application relates to the technical field of oilfield production engineering, in particular to a full-bore unlimited-stage fracturing sliding sleeve for horizontal wells, comprising a switching mechanism and a plurality of execution mechanisms, which jointly constitute a channel for fracturing fluid flow; the execution mechanism comprises an upper joint and a lower joint; the lower joint is provided with a fracture one, which is in communication with the channel; the inner side of the lower joint is provided with an inner cylinder; the inner cylinder is provided with a fracture two; under the action of the switching mechanism, the inner cylinder can slide along the axial direction and has corresponding first and second positions before and after sliding; when in the first position, the fracture two and the fracture one are axially misaligned; when in the second position, the fracture one and the fracture two are in correspondence and communication, and the inner cylinder and the lower joint form a stop cooperation, which facilitates the fracturing of the well section of the horizontal well; after the fracturing is completed, the special structure of the switching mechanism and the execution mechanism enables the switching mechanism to automatically adapt to different execution mechanisms and to perform multiple fracturing on the same well section of the horizontal well.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oilfield production engineering, in particular to a full-bore unlimited-stage fracturing sliding sleeve for horizontal wells. BACKGROUND

[0002] In oilfield production operations, staged fracturing technology is one of the core technologies for promoting the efficient development of low-permeability oil and gas reservoirs. The core operation logic is to divide the production area into multiple independent operation sections according to the geological characteristics and reservoir distribution of the target well section or rock formation. By carrying out fracturing operation on each independent section one by one, the original closed state of the reservoir is broken, and more abundant oil and gas seepage channels are constructed, thereby realizing the increase of single well production and oil and gas recovery.

[0003] In the fracturing implementation process of each operation section, two types of technical solutions are mainly used, namely, drag-type fracturing process and full-bore unlimited-stage fracturing process. Among them, the full-bore unlimited-stage fracturing process has outstanding advantages in operation flexibility, wellbore utilization rate and scene adaptability, and has been widely used in various oilfield production scenes.

[0004] The application range of the full-bore unlimited-stage fracturing process covers both open-hole completion and casing completion. Compared with the traditional ball sliding sleeve + packer staged fracturing process, the core difference between the two lies in the opening mode of the sliding sleeve.

[0005] In related technologies, for example, Chinese patent CN107178352B discloses a downhole full-bore unlimited-stage fracturing sliding sleeve. The opening of the sliding sleeve is realized by axial movement, which is more stable than the circumferential rotation mode. By changing the axial distance of the push block to correspond to different inner cylinders, it is realized that each specific actuator can only correspond to a specific switch mechanism, achieving accurate identification effect.

[0006] However, the above-mentioned downhole full-bore unlimited-stage fracturing sliding sleeve can only perform fracturing on the same well section once in actual use, and has poor adaptability. Moreover, a switch mechanism can only adapt to one actuator at a time, and when the switch mechanism needs to be changed, the switch mechanism needs to be removed and then the axial distance of the push block needs to be changed. Not only is the procedure complicated, but also the construction time is long, which affects the construction efficiency. SUMMARY

[0007] Therefore, it is necessary to provide a full-bore unlimited-stage fracturing sliding sleeve for horizontal wells to solve the problems that the current full-bore unlimited-stage fracturing sliding sleeve can only perform fracturing on the same well section once, resulting in poor adaptability and complex operation of changing the switch mechanism.

[0008] The above-mentioned purpose is realized by the following technical solutions:

[0009] The full-bore unlimited-stage fracturing sliding sleeve for horizontal wells comprises a switching mechanism and a plurality of executing mechanisms;

[0010] The executing mechanism comprises an upper joint and a lower joint, and an inner cylinder is arranged on the inner side of the lower joint, the inner cylinder is connected with the lower joint through N latches arranged in the circumferential direction, and the latches can elastically slide in the radial direction; a fracture I is arranged on the upper joint; a fracture II is arranged on the inner cylinder; under the action of the switching mechanism, the inner cylinder can slide in the axial direction, and has corresponding first and second positions before and after sliding, when in the first position, the fracture II and the fracture I are misaligned, and when in the second position, the fracture I and the fracture II are correspondingly communicated, and the inner cylinder and the lower joint form a stop cooperation;

[0011] The switching mechanism can rotate and comprises a sliding seat, the sliding seat is located on the inner side of the inner cylinder and can slide in the axial direction; N guide protrusions I are arranged on the sliding seat in the circumferential direction; a sliding groove I is arranged on each guide protrusion I and extends in the axial direction; the latch can be slidably inserted into the sliding groove I; a stop protrusion is arranged in each sliding groove I, the stop protrusion can form a stop cooperation with the latch and can drive the latch to move inward; two groups of guide protrusions II are arranged on the inner circumferential wall of each inner cylinder in the axial direction, N guide protrusions II in the same group are arranged in the circumferential direction, the guide protrusions II can form a guide cooperation with the guide protrusions I; the latch is located at the gap between the guide protrusions II in the same group and between the two groups of guide protrusions II; N locking blocks are arranged on the inner circumferential wall of each inner cylinder in the circumferential direction, the locking blocks can elastically slide in the radial direction, the locking blocks on different inner cylinders are misaligned in the circumferential direction at different angles relative to the gap between the guide protrusions II in the same group; an end is inserted into the sliding seat; the sliding seat can elastically slide in the axial direction relative to the end; N key blocks are arranged on the side wall of the end in the circumferential direction, the end can rotate relative to the sliding seat and can be rotated to correspondingly arrange the key blocks with the sliding grooves I or the locking blocks on different inner cylinders; an iris assembly is arranged between the sliding seat and the end, and the iris assembly can seal the inner cylinder in the transverse direction.

[0012] Further, the iris assembly comprises a plurality of sealing blocks, the plurality of sealing blocks are arranged in the circumferential direction and can be movably sleeved on the sliding seat and can be attached to the inner circumferential wall of the inner cylinder; each sealing block is connected with the sliding seat through a first elastic member, and under the action of the first elastic member, the sealing block has a tendency to move inward.

[0013] Further, an elastic layer I is arranged on the side wall of each sealing block.

[0014] Further, the attachment position of the inner cylinder and the sealing block is provided with an annular elastic layer II.

[0015] Further, the sealing block is made of an elastic material.

[0016] Further, the elastic material is rubber.

[0017] Further, the end head is internally provided with a cavity one, the cavity one is internally provided with a baffle one and a baffle two, the baffle one is fixedly connected with the end head, the baffle two is connected with the sliding base, and the baffle one and the baffle two divide the cavity one into two sub-cavities which are not communicated with each other, and one of the sub-cavities is configured to be capable of receiving liquid from the outside.

[0018] Further, the baffle one and the baffle two are connected with a first elastic member, after the end head is rotated relative to the sliding base, under the action of the first elastic member, the end head has a tendency to rotate to reset.

[0019] Further, the upper joint and the lower joint of the same execution mechanism are threadedly connected, and the lower joint and the upper joint of adjacent execution mechanisms are threadedly connected.

[0020] Further, the upper joint and the lower joint of the same execution mechanism are fixedly connected through a fastener, and the lower joint and the upper joint of adjacent execution mechanisms are fixedly connected through a fastener.

[0021] The beneficial effects of the present application are:

[0022] The present application relates to a full-bore unlimited-stage fracturing sliding sleeve for horizontal wells, a switching mechanism and a plurality of execution mechanisms are arranged, and the plurality of execution mechanisms jointly constitute a channel for conveying fracturing fluid; during the fracturing process, the inner cylinder is driven to move from the first position to the second position under the action of the switching mechanism, at this time, the fracture one, the fracture two and the channel are communicated, then the fracturing fluid is conveyed into the channel, and the fracturing fluid is sprayed out in turn after passing through the fracture two and the fracture one, so that the fracturing of the horizontal well section is realized; after the fracturing is completed, the inner cylinder is driven to move from the second position to the first position by using the special structure of the switching mechanism and the execution mechanism, so that the fracture two and the fracture one are axially dislocated, then the fracturing process is repeated, so that the multiple fracturing of the same well section is realized, and the applicability is improved; at the same time, the switching mechanism can be adapted to different execution mechanisms, so that the operation steps are simplified, the construction time is reduced, and the construction efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The cross-sectional structure schematic diagram of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application Figure 1 ;

[0024] Figure 2 The partial enlarged structure schematic diagram of the W in the Figure 1

[0025] Figure 3 The top view structure schematic diagram of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application

[0026] Figure 4 The cross-sectional view of the A-A direction in the Figure 3

[0027] Figure 5 ​​​Figure 4 Enlarged view of the structure at X;

[0028] Figure 6 For Figure 3 Sectional view along B-B;

[0029] Figure 7 For Figure 6 Enlarged view of the structure at Y;

[0030] Figure 8 Front view structural schematic diagram of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application;

[0031] Figure 9 For Figure 8 Sectional view along C-C;

[0032] Figure 10 Sectional view structural schematic diagram of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application; Figure 2

[0033] Figure 11 Sectional view structural schematic diagram of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application; Figure 3

[0034] Figure 12 For Figure 11 Enlarged view of the structure at Z;

[0035] Figure 13 Sectional view structural schematic diagram of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application; Figure 4

[0036] Figure 14 Stereoscopic sectional view structural schematic diagram of the inner cylinder of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application;

[0037] Figure 15 Stereoscopic structural schematic diagram of the latch of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application;

[0038] Figure 16 Stereoscopic structural schematic diagram of the switch mechanism of the full-bore unlimited-stage fracturing sliding sleeve for horizontal wells provided by the embodiment of the present application.

[0039] Wherein:

[0040] ​​​1, upper joint; 2, lower joint; 201, split one; 202, slot; 203, inclined surface structure two; 204, necked structure; 3, inner cylinder; 301, split two; 302, guide convex two; 3021, curved surface structure one; 303, cavity two; 304, conical annular surface structure one; 305, mounting groove; 4, bolt; 401, sliding ring; 402, inclined surface structure one; 403, inclined surface structure three; 5, first compression spring; 6, sliding seat; 601, guide convex one; 6011, curved surface structure two; 602, sliding groove one; 603, blocking convex; 604, baffle two; 605, cavity three; 606, connecting rod; 607, column convex; 608, conical annular surface structure two; 609, infusion channel; 610, telescopic groove; 7, locking block; 701, inclined surface structure four; 8, second compression spring; 9, end head; 901, key block; 9011, inclined surface structure five; 9012, convex block; 902, cavity one; 903, baffle one; 904, fixing sleeve; 905, conical annular surface structure three; 10, spring; 11, iris assembly; 1101, plugging block; 11011, sliding groove two; 1102, third compression spring; 12, torsion spring. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the present application with reference to the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0042] The serial numbers of the components in this paper, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any sequence or technical meaning. In this paper, "connection" and "coupling" include direct and indirect connection (coupling) unless otherwise specified. In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0043] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0044] The existing full-bore unlimited-stage fracturing sliding sleeve only supports single fracturing operation on the same well section of a horizontal well during use, and cannot perform secondary or multiple fracturing adjustment on the fractured well section according to reservoir dynamic changes or mining requirements, resulting in poor technical adaptability. Meanwhile, the existing full-bore unlimited-stage fracturing sliding sleeve adopts a fixed matching mode of "one-to-one", that is, one switch mechanism can only match one specific actuating mechanism; when the mining operation requirement changes and the type of the actuating mechanism matched by the switch mechanism needs to be changed, the switch mechanism in the well must be taken out as a whole, and after the axial spacing of the push block is adjusted on the ground, it is reinstalled and debugged in the well; this adjustment process is not only cumbersome in operation steps, but also requires a large amount of labor and time cost, and more importantly, the downhole operation environment is complex, and frequent pipe column tripping operation will increase the risk of wellbore collapse and well contamination, and also greatly prolong the construction period and reduce the overall mining operation efficiency.

[0045] Based on this, the embodiments of the present application provide a full-bore unlimited-stage fracturing sliding sleeve for horizontal wells, which is particularly suitable for oilfield mining operations.

[0046] Specifically, as shown in Figures 1 to 16 The full-bore unlimited-stage fracturing sliding sleeve for horizontal wells is provided with a switch mechanism and a plurality of actuating mechanisms, the plurality of actuating mechanisms are arranged along the vertical direction and jointly form a vertical tubular structure, the inner side of the vertical tubular structure forms a channel for conveying fracturing fluid, and the switch mechanism is located in the channel. Taking one of the actuating mechanisms as an example, the actuating mechanism includes an upper joint 1, the upper joint 1 is a tubular structure and is vertically arranged, and a lower joint 2 is threadedly inserted at the bottom of the upper joint 1, the lower joint 2 is a tubular structure and is vertically arranged, and the inner diameters of the lower joint 2 and the upper joint 1 are equal; an inner cylinder 3 is vertically arranged on the inner side of the upper joint 1 and the lower joint 2, both ends of the inner cylinder 3 are open, and the outer diameter of the inner cylinder 3 is equal to the inner diameter of the upper joint 1; the inner cylinder 3 is connected with the lower joint 2 through N circumferentially arranged bolts 4, so as to lock the initial position of the inner cylinder 3.

[0047] With N equal to three as an example, three plugs 4 are uniformly arranged in the circumferential direction. With one of the plugs 4 as an example, the main body of the plug 4 is long strip-shaped, and the cross-sectional shape is square, and is horizontally arranged during installation; a cavity two 303 is formed in the inner wall of the inner cylinder 3, the cavity two 303 is a columnar structure, and is arranged vertically with the inner cylinder 3, a slot 202 is formed on the inner wall of the lower connector 2, the middle part of the plug 4 is inserted into the cavity two 303, and the inner end penetrates through the inner wall of the inner cylinder 3 and is located inside the inner cylinder 3, and the outer end penetrates through the outer wall of the inner cylinder 3 and is located in the slot 202; the middle part of the plug 4 is provided with a sliding ring 401, the sliding ring 401 and the cavity two 303 are coaxially arranged, and can slide along the extension direction of the cavity two 303, and can form a stop cooperation with the outer wall of the cavity two 303 to limit the limit position of the plug 4 sliding outward; the plug 4 is connected with the inner cylinder 3 through the second elastic member, and under the action of the second elastic member, the plug 4 can elastically slide in the radial direction, which is convenient for resetting; the second elastic member can be a first compression spring 5, the first compression spring 5 is sleeved on the middle part of the plug 4, and is connected between the inner wall of the sliding ring 401 and the inner wall of the cavity two 303; the outer end wall of the plug 4 is inclined structure one 402, and is arranged inclined upward and outward at the same time; the junction between the slot 202 and the inner wall of the lower connector 2 is provided with inclined structure two 203, the inclination of the inclined structure two 203 is equal to that of the inclined structure one 402, which is convenient for guiding the plug 4 to separate from the slot 202, so that the inner cylinder 3 can slide axially relative to the lower connector 2, and the crack two 301 and the crack one 201 correspond and communicate. With two adjacent actuators as an example, the lower connector 2 of the upper actuator is threadedly sleeved on the upper connector 1 of the lower actuator during installation.

[0048] The inner wall of the lower connector 2 is provided with a crack one 201, which is composed of a plurality of hole structures; the inner wall of the inner cylinder 3 is provided with a crack two 301, which is composed of a plurality of hole structures; the inner wall near the bottom of the lower connector 2 is a necked structure 204, and the large end is arranged upward; the outer wall of the bottom of the inner cylinder 3 is a conical surface structure one 304, and the taper is equal to that of the necked structure 204. Under the action of the switch mechanism, the inner cylinder 3 can slide axially, and has corresponding first and second positions before and after sliding, initially, the inner cylinder 3 is in the first position, the crack two 301 and the crack one 201 are axially misaligned, and the crack two 301 is located above the crack one 201; when in the second position, the crack one 201 and the crack two 301 correspond and communicate, the necked structure 204 and the conical surface structure one 304 overlap, so that the inner cylinder 3 and the lower connector 2 form a stop cooperation, which is convenient for locking the position of the inner cylinder 3, at this time, the fracturing fluid can be transported into the channel, the fracturing fluid is sprayed out after passing through the crack two 301 and the crack one 201 in turn, and the horizontal well section is fractured.

[0049] The switch mechanism can rotate and comprises a slide 6, which is in a columnar structure, is vertically inserted into the inner cylinder 3, and can slide along the axial direction; three guide protrusions one 601 are uniformly distributed on the circumferential side wall of the slide 6 in the circumferential direction, are in a strip structure, and extend along the direction parallel to the axis of the slide 6; a sliding groove one 602 is formed on the outward side wall of each guide protrusion one 601, is symmetrically arranged with respect to the guide protrusion one 601, is located at the middle part of the guide protrusion one 601 in the circumferential direction, extends along the direction parallel to the axis of the slide 6, and simultaneously extends inward to the circumferential side wall of the slide 6; a stop protrusion 603 is correspondingly arranged on the two slot side walls close to the bottom of each sliding groove one 602; four inclined surface structures three 403 are arranged on the side wall of the inner end of the plug 4 towards the sliding ring 401, are divided into two groups, are respectively located on the left and right sides of the plug 4, are symmetrically arranged with respect to the plug 4, the two inclined surface structures three 403 in the same group are arranged along the axial direction, are symmetrically arranged with respect to the plug 4, and jointly form a V-shaped shape, the tip of the V-shaped shape faces the sliding ring 401, the inclined surface structure three 403 can form a stop cooperation with the stop protrusion 603, and when the stop protrusion 603 and the inclined surface structure three 403 located above form the stop cooperation, the stop protrusion 603 drives the plug 4 to move inward through the inclined surface structure three 403 located above along with the downward movement of the slide 6, until the stop protrusion 603 moves to the tip of the V-shaped shape formed by the two inclined surface structures three 403 in the same group, at this time, the plug 4 moves inward to the limit position, and the inclined surface structure one 402 and the inclined surface structure two 203 coincide.

[0050] The inner peripheral wall of each inner cylinder 3 is provided with two groups of guide protrusions 302 in the axial direction, three guide protrusions 302 in the same group are arranged equidistantly in the circumferential direction, a gap is formed between adjacent guide protrusions 302, and the guide protrusions 302 in different groups are arranged correspondingly in the axial direction; the guide protrusions are arc-shaped structures and are coaxial with the inner cylinder 3, the top of the upper guide protrusion 302 gradually decreases from the middle to both ends, so that two curved structures 3021 are formed, the two curved structures 3021 are symmetrically arranged about the guide protrusion 302 and form a V-shaped structure with the tip pointing upward, and the bottom of the lower guide protrusion 302 gradually increases from the middle to both ends, so that two curved structures 3021 are formed, the two curved structures 3021 are symmetrically arranged about the guide protrusion 302 and form a V-shaped structure with the tip pointing downward; the upper and lower end faces of each guide protrusion 601 are curved structures 6011, the upper curved structure 6011 extends upward and inward, and the lower curved structure 6011 extends downward and inward. When the sliding seat 6 slides downward, the lower curved structure 6011 can form a guide fit with the upper curved structure 3021, facilitating the rotation of the switch mechanism, so that the guide protrusion 601 can be rotated to correspond to the gap between the adjacent guide protrusions 302 in the same group, thereby realizing automatic correction of the position, and with the continuous downward sliding of the sliding seat 6, the guide protrusion 601 can be embedded into the gap.

[0051] The bolt 4 is located in the gap between the guide protrusions 302 in the same group and is located between the two groups of guide protrusions 302 in the axial direction; the inner peripheral wall of each inner cylinder 3 is uniformly provided with three mounting grooves 305 in the circumferential direction, and the mounting grooves 305 are located below the two groups of guide protrusions 302; a locking block 7 is inserted into each mounting groove 305, the locking block 7 is connected to the inner cylinder 3 through a third elastic member, and under the action of the third elastic member, the locking block 7 can elastically slide in the radial direction; the third elastic member can be a second compression spring 8, the second compression spring 8 is inserted into the mounting groove 305 during installation, and the two ends are connected between the groove bottom of the mounting groove 305 and the outer side wall of the locking block 7, under the action of the second compression spring 8, the locking block 7 has a tendency to move inward; the locking blocks 7 on different inner cylinders 3 are different in the circumferential direction with respect to the gap between the guide protrusions 302 in the same group, so that each actuator is different.

[0052] The sliding seat 6 is provided with a cavity three 605 near the bottom, which divides the sliding seat 6 into two parts, and a plurality of connecting rods 606 are connected between the two parts and extend in the vertical direction, and the plurality of connecting rods 606 are uniformly arranged in the circumferential direction; the bottom of the sliding seat 6 is inserted with an end 9, the main body of the end 9 is a columnar structure, and is coaxially arranged with the sliding seat 6; a fourth elastic member is connected between the sliding seat 6 and the end 9, and under the action of the fourth elastic member, the sliding seat 6 can elastically slide along the axial direction relative to the end 9; a columnar protrusion 607 is coaxially arranged on the top of the cavity three 605 on the sliding seat 6; a fixing sleeve 904 is coaxially arranged on the top of the end 9, and the fixing sleeve 904 is slidably sleeved on the columnar protrusion 607; the fourth elastic member can be a spring 10, which is sleeved on the columnar protrusion 607 and the fixing sleeve 904.

[0053] The inner side wall of each locking block 7 is provided with two inclined surface structures four 701, which are arranged in the axial direction and symmetrically arranged about the locking block 7, and together form a V-shaped shape, the tip of the V-shaped shape is arranged inward, and a V-shaped notch is arranged at the connection between the upper inclined surface structure four 701 and the top surface, and the tip of the notch is arranged downward. Three key blocks 901 are equally and circumferentially arranged on the peripheral side wall of the end 9, two inclined surface structures five 9011 are arranged on the outer side wall of each key block 901, which are arranged in the axial direction and together form a V-shaped shape, and the tips of the V-shaped shape are arranged outward, the inclination of the lower inclined surface structure five 9011 and the upper inclined surface structure four 701 is consistent, and the inclination of the upper inclined surface structure five 9011 and the lower inclined surface structure four 701 is consistent; a protrusion 9012 is arranged on the lower inclined surface structure five 9011, which can be embedded into the notch on the locking block 7, so as to realize the clamping connection between the locking block 7 and the key block 901. The junctions between the upper and lower end surfaces and the peripheral side wall of the sliding seat 6 are provided with a conical annular surface structure two 608, and the large end of the upper conical annular surface structure two 608 is arranged downward, when the sliding seat 6 slides upward, it can form a stop cooperation with the lower inclined surface structure four 701, so as to guide the locking block 7 to be inserted into the installation groove 305 inward, avoiding movement interference; the large end of the lower conical annular surface structure two 608 is arranged upward, when the sliding seat 6 slides downward, it can form a stop cooperation with the upper inclined surface structure four 701, so as to guide the locking block 7 to be inserted into the installation groove 305 inward, avoiding movement interference.

[0054] The end 9 can rotate relative to the sliding seat 6, and can be rotated to correspond to the locking block 7 on the key block 901 and the different inner barrels 3, so as to facilitate the clamping of the key block 901 and the locking block 7 of the corresponding actuator, so as to be able to crack the target well section, and then make the switch mechanism adapt to different actuators, simplify the operation steps, reduce the construction time, and improve the construction efficiency. And can be rotated to correspond to the sliding groove one 602, so as to facilitate the movement of the inner barrel 3 from the second position to the first position, so that the crack two 301 and the crack one 201 are axially dislocated, and then the cracking process is repeated, so that the same well section can be cracked multiple times, and the applicability is improved.

[0055] The iris assembly 11 is arranged between the sliding seat 6 and the end 9, the iris assembly 11 is located in the cavity three 605, and the iris assembly 11 comprises a plurality of blocking blocks 1101. The top of each blocking block 1101 is provided with a sliding groove two 11011 extending in a direction perpendicular to the sliding seat 6. The blocking block 1101 is movably sleeved on the connecting rod 606 through the sliding groove two 11011 during installation. Figure 13 As shown in the drawings, viewed from above, the blocking block 1101 is approximately an obtuse triangle, and the outer side wall of the blocking block 1101 is a circular arc surface, which is convenient for abutting with the inner peripheral wall of the inner barrel 3. In the clockwise direction, the side wall of the blocking block 1101 located on the front side is a vertical surface, and the side wall of the blocking block 1101 located on the rear side is a circular arc surface close to the part of the side wall of the blocking block 1101 located on the front side. The plurality of blocking blocks 1101 can form a complete circular ring structure, which is convenient for cooperating with the sliding seat 6 to block the inner barrel 3 in the transverse direction.

[0056] In order to facilitate the movement of the plurality of blocking blocks 1101 to form a complete circular ring structure, the intersection between the top end surface and the peripheral side wall of the end 9 is provided with a conical ring surface structure three 905, and the large end of the conical ring surface structure three 905 is arranged downward. The bottom of each blocking block 1101 is provided with a conical ring surface structure four, and the taper of the conical ring surface structure four is equal to the taper of the conical ring surface structure three 905, so as to facilitate the guiding cooperation. When the sliding seat 6 slides downward relative to the end 9, the sliding seat 6 synchronously drives the blocking block 1101 to slide downward relative to the end 9. Under the guiding cooperation between the conical ring surface structure four and the conical ring surface structure three 905, the blocking block 1101 moves outward and finally forms a complete circular ring structure. In order to facilitate the automatic reset of the blocking block 1101, a first elastic member is connected between the blocking block 1101 and the connecting rod 606. Under the action of the first elastic member, the blocking block 1101 has a tendency to move inward. The first elastic member can be a third compression spring 1102, which is inserted into the sliding groove two 11011 and has two ends located between the inner end of the sliding groove two 11011 and the connecting rod 606, respectively.

[0057] To facilitate the relative rotation between the end 9 and the slide 6, the cavity one 902 is set in the end 9 near the top, and the cavity one 902 and the fixed sleeve 904 are correspondingly set; the baffle one 903 and the baffle two 604 are vertically inserted in the cavity one 902, the bottom of the column convex 607 is provided with the expansion slot 610, which can extend upward to the inside of the slide 6, the baffle two 604 penetrates the top of the end 9 upward during installation, and is inserted into the fixed sleeve 904 and can be slidably inserted into the expansion slot 610, ensuring that the position of the baffle two 604 in the cavity one 902 is unchanged; the baffle one 903 is fixedly connected with the end 9; the baffle one 903 and the baffle two 604 divide the cavity one 902 into two separate cavities along the circumference, and the infusion channel 609 is provided in the inside of the slide 6, which is in communication with one of the cavities four formed between the column convex 607 and the fixed sleeve 904, so that the liquid such as hydraulic oil outside can be introduced into the cavity, so that under the action of hydraulic pressure, the end 9 can be driven to rotate relative to the slide 6 through the baffle one 903, and then the key block 901 and the locking block 7 on the different inner barrels 3 can be correspondingly arranged.

[0058] Optionally, to realize the upper sealing of the well section, a liquid bag is arranged on the slide 6, which is located above the crack two 301 and can synchronously slide along the axial direction with the slide 6, and can block the inner barrel 3 in the transverse direction when the liquid is injected.

[0059] In the preparation stage, first, the actuator is assembled: the upper joint 1 and the lower joint 2 are threadedly connected, then the assembled upper joint 1 and lower joint 2 are vertically arranged, with the upper joint 1 located above, then the inner barrel 3 is inserted into the inside of the upper joint 1 and the lower joint 2 from top to bottom, driven by gravity or external force to move downward, and moved to the position where the bolt 4 is inserted into the slot 202, the first compression spring 5 is first compressed and then released, at this time the position of the inner barrel 3 inside the lower joint 2 is locked, and is located at the first position, the crack one 201 and the crack two 301 are axially misaligned, and the crack two 301 is located above the crack one 201; then the different actuators are assembled together: the lower joint 2 and the upper joint 1 of adjacent actuators are threadedly connected, so that multiple actuators form a tubular structure, and a channel for conveying fracturing fluid is formed inside the tubular structure. The guide convex two 302 of different actuators are correspondingly arranged, and the locking blocks 7 on the inner barrels 3 are misaligned at different angles along the circumference relative to the gap between the same group of adjacent guide convex two 302, so that each actuator is different.

[0060] During use, firstly, the assembled plurality of execution mechanisms are put into the horizontal well; then hydraulic oil is inputted into the cavity 1 902 through the liquid delivery channel 609, under the hydraulic action, the end 9 is driven to rotate relative to the slide 6 by the baffle 1 903, so that the key block 901 and the locking block 7 on the target inner cylinder 3 are correspondingly arranged; then the switch mechanism is put into the channel; then the switch mechanism is driven to move along the channel to the target execution mechanism.

[0061] During the movement of the switch mechanism, if the gap between the guide convex 1 601 and the same group of adjacent guide convex 2 302 located above the first execution mechanism is circumferentially misaligned, when the slide 6 moves to the guide cooperation formed by the curved surface structure 2 6011 located below and the curved surface structure 1 3021 located above, with the continuous movement of the slide 6, the switch mechanism is rotated to the gap between the guide convex 1 601 and the same group of adjacent guide convex 2 302 under the guidance of the curved surface structure 1 3021 located above, and with the continuous sliding of the slide 6, the guide convex 1 601 is embedded into the gap, and the latch 4 is inserted into and slides along the slot 1 602.

[0062] Before the switch mechanism moves to the target execution mechanism, when the stop convex 603 and the inclined surface structure 3 403 located above form a stop cooperation, with the continuous movement of the slide 6, the stop convex 603 drives the latch 4 to move inward through the inclined surface structure 3 403 located above, and the first compression spring 5 is synchronously compressed, until the stop convex 603 moves to the V-shaped tip formed by the two inclined surface structures 3 403 of the same group, at this time, the latch 4 moves inward to the limit position, since the outer end of the latch 4 is still located in the slot 202, and the inner cylinder 3 is not subjected to downward force, the inner cylinder 3 will not move; after the stop convex 603 passes the V-shaped tip formed by the two inclined surface structures 3 403 of the same group, with the continuous movement of the slide 6, the first compression spring 5 is released to drive the latch 4 to reset; and since the key block 901 only corresponds to the locking block 7 on the target inner cylinder 3, the key block 901 will not interfere with the movement of the locking block 7 on other inner cylinders 3, so as to ensure that the switch mechanism can smoothly pass through other execution mechanisms.

[0063] When the switch mechanism moves to the target actuator, the protrusion 9012 is inserted into the gap on the locking block 7, so that the key block 901 and the locking block 7 are clamped, at this time the position of the end head 9 is locked, the blocking protrusion 603 moves to the V-shaped tip formed by the two inclined structures three 403 of the same group, the latch 4 moves inward to the limit position, the inclined structure one 402 and the inclined structure two 203 coincide; then drive the sliding seat 6 to continue to move, the sliding seat 6 synchronously drives the blocking block 1101 to approach the end head 9, under the guidance of the conical ring surface structure four and the conical ring surface structure three 905, the third compression spring 1102 is compressed, and the blocking block 1101 moves outward, and finally forms a complete annular structure, so as to cut off the channel together with the sliding seat 6 along the transverse direction; then drive the sliding seat 6 to continue to move, the sliding seat 6 synchronously drives the inner cylinder 3 away from the upper connector 1 through the clamping between the key block 901 and the locking block 7, the inner cylinder 3 drives the latch 4 to move along the inclined structure two 203, guides the latch 4 to disengage from the insertion slot 202, and the outer end of the latch 4 is then pushed against the inner circumferential wall of the lower connector 2 and slides along the inner circumferential wall of the lower connector 2; when the retraction structure 204 and the conical ring surface structure one 304 coincide, the inner cylinder 3 reaches the limit position downward, at this time the crack two 301 and the crack one 201 correspond and communicate, the switch mechanism stops moving, then the liquid in the liquid chamber is injected to make it swell and block the channel in the transverse direction, at this time the target well section is blocked into a sealed chamber by the annular structure formed by the liquid chamber, the blocking block 1101 and the sliding seat 6, then the fracturing fluid is filled into the sealed chamber, and the fracturing fluid is sprayed out after passing through the crack two 301 and the crack one 201 in turn, so as to realize the fracturing of the target well section.

[0064] When the target well section needs to be fractured twice, first, the liquid in the liquid chamber is withdrawn to make the liquid chamber shrink; then hydraulic oil can be input into the cavity one 902 through the liquid delivery channel 609, under the hydraulic action, the end head 9 is driven to rotate relative to the sliding seat 6 through the baffle one 903, so that the key block 901 and the latch 4 are correspondingly arranged, or the hydraulic oil in the cavity one 902 can be pumped out through the liquid delivery channel 609, under the pressure difference, the end head 9 is driven to rotate relative to the sliding seat 6 through the baffle one 903, so that the key block 901 and the latch 4 are correspondingly arranged; then drive the sliding seat 6 to move away from the end head 9, the third compression spring 1102 is released, and the blocking block 1101 is driven to move inward to reset the blocking block 1101; when the key block 901 moves to the stop of the latch 4, with the continuous movement of the sliding seat 6, the sliding seat 6 synchronously drives the inner cylinder 3 to approach the upper connector 1, so that the crack two 301 and the crack one 201 are gradually misaligned until the latch 4 is reinserted into the insertion slot 202; then repeat the process of making the crack two 301 and the crack one 201 correspond and communicate, then fill the fracturing fluid into the sealed chamber, so as to realize the secondary fracturing of the target well section.

[0065] When the target well section needs to be fractured three times or more, the above-mentioned secondary fracturing process can be repeated.

[0066] It should be noted that when the switch mechanism is inside the channel, hydraulic oil can be input into cavity one 902 through the infusion channel 609, under the action of hydraulic pressure, the end head 9 is driven to rotate relative to the sliding seat 6 through the baffle one 903, so that the key block 901 and the locking block 7 on the other target inner cylinder 3 are correspondingly arranged, and the hydraulic oil in the cavity one 902 can also be pumped out through the infusion channel 609, under the action of pressure difference, the end head 9 is driven to rotate relative to the sliding seat 6 through the baffle one 903, so that the key block 901 and the locking block 7 on the other target inner cylinder 3 are correspondingly arranged, so that the switch mechanism in the well can adapt to different executing mechanisms, while simplifying the operation steps, it is beneficial to reduce the construction time and improve the construction efficiency.

[0067] In further embodiments, in order to improve the sealing performance of the iris assembly 11 when sealing the inner cylinder 3 in the transverse direction, an elastic layer one is arranged on the side wall of each sealing block 1101. The elastic layer one can be made of an elastic material such as rubber. In this way, when the plurality of sealing blocks 1101 form a complete circular ring structure, the elastic layer one can deform to fill the gaps and improve the sealing effect.

[0068] In other embodiments, in order to improve the sealing performance of the iris assembly 11 when sealing the inner cylinder 3 in the transverse direction, an annular elastic layer two can also be arranged at the abutting position of the inner cylinder 3 and the sealing block 1101. The elastic layer two can be made of an elastic material such as rubber. In this way, when the plurality of sealing blocks 1101 form a complete circular ring structure, the elastic layer two can deform to fill the gaps and improve the sealing effect.

[0069] In other embodiments, in order to improve the sealing performance of the iris assembly 11 when sealing the inner cylinder 3 in the transverse direction, the sealing block 1101 can also be made of an elastic material such as rubber. In this way, when the plurality of sealing blocks 1101 form a complete circular ring structure, the sealing block 1101 can deform by itself to fill the gaps and improve the sealing effect.

[0070] In other embodiments, in order to realize automatic reset of the end head 9 after rotating relative to the sliding seat 6, a second elastic member is connected between the baffle one 903 and the baffle two 604. After the end head 9 rotates relative to the sliding seat 6, the end head 9 has a tendency to rotate to reset under the action of the second elastic member.

[0071] Specifically, the second elastic member can be a torsion spring 12, which is inserted into the baffle one 903 and fixedly connected to the baffle one 903 and the baffle two 604 at both ends.

[0072] During use, after the end head 9 rotates relative to the sliding seat 6, the torsion spring 12 deforms and stores energy; during the process of restoring normal pressure in the cavity one 902, the torsion spring 12 drives the end head 9 to rotate relative to the sliding seat 6 through the baffle one 903, thereby realizing reset.

[0073] In other embodiments, in order to improve the connection stability between the upper joint 1 and the lower joint 2 of the same actuating mechanism, and between the lower joint 2 and the upper joint 1 of the adjacent actuating mechanism, the upper joint 1 and the lower joint 2 of the same actuating mechanism, and the lower joint 2 and the upper joint 1 of the adjacent actuating mechanism are fixedly connected by fasteners.

[0074] Specifically, the fastener can be provided with an anti-rotation pin. For the upper joint 1 and the lower joint 2 of the same actuating mechanism, the anti-rotation pin is radially inwardly penetrated through the side wall of the upper joint 1 during installation, and is screwed or frictionally inserted into the inside of the side wall of the lower joint 2. For the lower joint 2 and the upper joint 1 of the adjacent actuating mechanism, the anti-rotation pin is radially inwardly penetrated through the side wall of the lower joint 2 during installation, and is screwed or frictionally inserted into the inside of the side wall of the upper joint 1.

[0075] In other embodiments, in order to improve the sealing between the upper joint 1 and the lower joint 2, a sealing member such as a sealing ring is arranged at the connection between the upper joint 1 and the lower joint 2 to achieve sealing.

[0076] In other embodiments, the liquid capsule can also be replaced by an existing packer or dissolvable bridge plug to achieve unilateral plugging of the channel. At this time, the crack two 301 and the crack one 201 are both located below the end 9, and the packer or dissolvable bridge plug is located below the crack one 201.

[0077] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present disclosure.

[0078] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A full-bore, unlimited-stage fracturing sleeve for horizontal wells, characterized in that, Includes a switching mechanism and multiple actuators; The actuator includes an upper connector (1) and a lower connector (2). An inner cylinder (3) is provided inside the lower connector (2). The inner cylinder (3) is connected to the lower connector (2) by N pins (4) arranged circumferentially. The pins (4) can slide elastically in the radial direction. A first slit (201) is provided on the lower connector (2). A second slit (301) is provided on the inner cylinder (3). Under the action of the switching mechanism, the inner cylinder (3) can slide axially and has a first position and a second position before and after sliding. When it is in the first position, the second slit (301) and the first slit (201) are misaligned. When it is in the second position, the first slit (201) and the second slit (301) are connected to each other, and the inner cylinder (3) and the lower connector (2) form a stop fit. The switching mechanism is rotatable and includes a slide (6), which is located inside the inner cylinder (3) and can slide along the axial direction; N guide protrusions (601) are arranged circumferentially on the slide (6); each guide protrusion (601) is provided with a groove (602), which extends axially; the pin (4) can be slidably inserted into the groove (602); each groove (602) is provided with a stop protrusion (603), which can form a stop engagement with the pin (4) and can drive the pin (4) to move inward; two sets of guide protrusions (302) are arranged axially at intervals on the inner circumferential wall of each inner cylinder (3), and the N guide protrusions (302) in the same set are arranged circumferentially at intervals, and the guide protrusions (302) can form a guiding engagement with the guide protrusions (601); the pin (4) is located in the same set of adjacent guide protrusions (302). The gap between the two sets of guide protrusions (302) is located between the two sets of guide protrusions (302); N locking blocks (7) are arranged circumferentially on the inner wall of each inner cylinder (3). The locking blocks (7) can slide elastically in the radial direction. The locking blocks (7) on different inner cylinders (3) are misaligned at different angles relative to the gap between adjacent guide protrusions (302) in the same set of guide protrusions (302) in the circumferential direction; an end (9) is inserted on the slide (6); the slide (6) can slide elastically in the axial direction relative to the end (9); N key blocks (901) are arranged circumferentially on the side wall of the end (9). The end (9) can rotate relative to the slide (6) and can rotate until the key block (901) and the first slide groove (602) or the locking blocks (7) on different inner cylinders (3) are correspondingly arranged; an iris assembly (11) is arranged between the slide (6) and the end (9). The iris assembly (11) can block the inner cylinder (3) in the transverse direction.

2. The horizontal well full-bore unlimited-stage fracturing sliding sleeve according to claim 1, characterized in that, The iris assembly (11) includes multiple blocking blocks (1101), which are arranged circumferentially and can be movably fitted onto the slide (6) and can fit against the inner circumferential wall of the inner cylinder (3). Each blocking block (1101) is connected to the slide (6) through a first elastic element. Under the action of the first elastic element, the blocking block (1101) has a tendency to move inward.

3. The horizontal well full-bore unlimited-stage fracturing sliding sleeve according to claim 2, characterized in that, Each sealing block (1101) has an elastic layer on its sidewall.

4. The horizontal well full-bore unlimited-stage fracturing sliding sleeve according to claim 2, characterized in that, An annular elastic layer 2 is provided at the contact position between the inner cylinder (3) and the sealing block (1101).

5. The horizontal well full-bore unlimited-stage fracturing sliding sleeve according to claim 2, characterized in that, The sealing block (1101) is made of elastic material.

6. The horizontal well full-bore unlimited-stage fracturing sleeve according to claim 5, characterized in that, The elastic material is rubber.

7. The horizontal well full-bore unlimited-stage fracturing sliding sleeve according to claim 1, characterized in that, The end (9) has a cavity 1 (902) inside. A baffle 1 (903) and a baffle 2 (604) are inserted in the cavity 1 (902). The baffle 1 (903) is fixedly connected to the end (9), and the baffle 2 (604) is connected to the slide (6). The baffle 1 (903) and the baffle 2 (604) divide the cavity 1 (902) into two non-communicating sub-cavities. One of the sub-cavities is configured to receive liquid from the outside.

8. The horizontal well full-bore unlimited-stage fracturing sleeve according to claim 7, characterized in that, A first elastic element is connected between baffle one (903) and baffle two (604). After the end (9) rotates relative to the slide (6), the end (9) tends to rotate to the reset position under the action of the first elastic element.

9. The horizontal well full-bore unlimited-stage fracturing sleeve according to claim 1, characterized in that, The upper connector (1) and lower connector (2) of the same actuator are threaded together; the lower connector (2) and upper connector (1) of adjacent actuators are threaded together.

10. The horizontal well full-bore unlimited-stage fracturing sliding sleeve according to claim 9, characterized in that, The upper connector (1) and lower connector (2) of the same actuator are fixedly connected by fasteners, as are the lower connector (2) and upper connector (1) of adjacent actuators.

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