Underground absolute differential pressure opening isolation device and use method
By designing an isolation device with absolute pressure difference opening downhole, using structures such as shear parts and breathable holes, the connection of the oil sleeve, isolation and the establishment of the oil pipe and the formation channel are achieved, which solves the multifunctional needs that cannot be achieved simultaneously in the existing technology, and ensures the reliability and sealing of circulation.
Patent Information
- Application Number
- CN202510601419.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-12
- Publication Date
- 2025-07-18
AI Technical Summary
The prior art cannot simultaneously realize the unidirectionality of oil sleeves in the downward flow of horizontal well pipe columns, isolation of oil sleeves after being lowered, and establishment of passage between the oil pipes and formations after operation is completed.
An isolation device with absolute pressure difference opening of downhole is designed, including an upper joint, a lower joint, a valve seat, a valve core and a support sleeve. Through the shearing action of the shearing part, the oil sleeve is connected, isolation and the establishment of channels, and the air permeability hole and elastic limiting part are used to ensure the smooth movement and limit of the valve core.
The oil sleeve connection is achieved in the process of downstream pipe string, the oil sleeve isolation after downstream, and the channel between the oil pipe and the formation is established after operation is completed. The structure is simple and reliable, ensuring the sealing and connectivity of circulation.
Smart Images
Figure CN120331715A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of downhole reservoir fracturing and reconstruction tools in oil and gas fields, and particularly relates to an isolation device opened by absolute differential pressure downhole and a using method thereof. Background Art
[0002] Currently, the horizontal well staged completion string is applied to horizontal wells that require acid fracturing reconstruction in the production section for a long time. Open-hole horizontal well staged fracturing is an effective technology for developing low-porosity, low-permeability, and tight gas reservoirs. During the process of running in the horizontal well string, it is necessary to ensure the unidirectional connection between the tubing and the casing during the running process of the string. After the string is in place, it is necessary to isolate the tubing and the casing to ensure the setting of the packer at the upper part of the string. After the entire string running operation is completed, it is necessary to open it by absolute differential pressure to establish a channel between the tubing and the formation for acid fracturing reconstruction. However, there is currently no isolation device that can meet the requirements of the above three links at the same time. Summary of the Invention
[0003] The purpose of the present invention is to address the deficiencies of the prior art and provide an isolation device opened by absolute differential pressure downhole and a using method thereof, which realizes the unidirectional connection between the tubing and the casing during the running process of the string, the isolation between the tubing and the casing after the string is in place, and the establishment of a channel between the tubing and the formation after the string operation is completed.
[0004] To solve the above technical problems, in a first aspect, the present invention provides an isolation device opened by absolute differential pressure downhole, including:
[0005] An upper sub, on which a first side through hole is opened;
[0006] A lower sub, one end of which is inserted into the upper sub and fixedly connected to the upper sub, and a first limiting step is provided on the inner wall of the lower sub;
[0007] A valve seat, which is slidably arranged in the upper sub, a second side through hole is opened on the valve seat, the valve seat closes the first side through hole of the upper sub, a channel is provided between the valve seat and the upper sub, so that the second side through hole is communicated with the inside of the lower sub through the channel, and a second limiting step is provided on the inner wall of the valve seat;
[0008] A valve core, which is slidably arranged in the valve seat, a third side through hole is opened on the valve core, the third side through hole is arranged corresponding to the second side through hole, the valve core and the valve seat are connected by a first shear member, and after the first shear member is cut off, the valve core can axially move to abut against the second limiting step, so that the third side through hole is not communicated with the second side through hole;
[0009] A support sleeve is slidably disposed at one end of the lower joint inserted into the upper joint. The support sleeve abuts against the valve seat. The support sleeve and the lower joint are connected by a second shear member. The shear strength of the second shear member is greater than that of the first shear member. After the second shear member is cut off, the valve seat can push the support sleeve to move until it abuts against the first limit step, so that the first side through hole is opened.
[0010] In some embodiments, a groove is formed on the valve core, and an elastic limit member is disposed in the groove. After the valve core moves axially to abut against the second limit step, the elastic limit member pops open to limit the rebound of the valve core.
[0011] In some embodiments, a vent hole is formed on the valve seat. The vent hole is close to the second limit step and is used to discharge the air between the valve core and the valve seat during the process of the valve core moving axially to abut against the second limit step.
[0012] In some embodiments, the vent hole and the second limit step are located on the side of the second side through hole away from the lower joint.
[0013] In some embodiments, the valve seat includes a contact section, a vent section, and a flow-through section connected in sequence. The contact section fits against the inner wall of the upper joint and is used to close the first side through hole. The vent section is not in contact with the upper joint or the valve core. The second limit step is arranged at one end of the vent section away from the contact section. The flow-through section is not in contact with the upper joint, and the inner wall of the flow-through section fits against the valve core.
[0014] In some embodiments, a first sealing ring is disposed on the valve seat and is arranged on both sides of the first side through hole.
[0015] In some embodiments, a second sealing ring is disposed between the part of the lower joint inserted into the upper joint and the upper joint.
[0016] In some embodiments, a third sealing ring and a fourth sealing ring are disposed on the valve core. The third sealing ring is arranged on both sides of the third side through hole, and the fourth sealing ring is arranged at one end of the valve core away from the lower joint, so as to seal between the valve core and the contact section of the valve seat.
[0017] In some embodiments, a plurality of notches are formed at one end of the valve seat close to the lower joint, and the channel is communicated with the inside of the lower joint through the notches.
[0018] In a second aspect, the present invention provides a method for using an isolation device opened by an absolute pressure difference underground, including:
[0019] Install the isolation device at the lower end of the oil pipe to form a pipe string, lower the pipe string, and the inside of the upper joint is communicated with the lower joint through the third side through hole, the second side through hole, and the channel, so that the oil pipe and the casing establish a circulation;
[0020] After the pipe string reaches the specified depth, a steel ball is dropped to seat on the valve core, blocking the third side through-hole. The tubing is pressured until the first shear member is cut off, and the valve core moves to abut against the second limit step, causing the second side through-hole and the third side through-hole to be non-communicating, isolating the tubing and the casing.
[0021] After the packer in the upper part of the pipe string is set and the pipe string running operation is completed, the tubing is pressured until the second shear member is cut off. The valve seat moves with the support sleeve to abut against the first limit step, and the first side through-hole of the upper joint opens, establishing communication between the tubing and the formation, and starting the acid fracturing operation.
[0022] The beneficial effects of the present invention are as follows:
[0023] 1. In the initial state of the present invention, the upper joint is communicated with the lower joint through the third side through-hole, the second side through-hole, and the passage between the valve seat and the upper joint, and the oil-casing circulation is established. After the first shear member is cut off, the valve core moves, and the passage formed by the third side through-hole and the second side through-hole is disconnected, isolating the oil-casing. After the second shear member is cut off, the valve seat moves, and the first side through-hole opens, establishing communication between the tubing and the formation. This isolation device can realize three functions: oil-casing communication, oil-casing isolation, and establishment of communication between the tubing and the formation, and has a simple and reliable structure.
[0024] 2. By providing a vent hole in the present invention, the smooth movement of the valve core after the first shear member is cut off is ensured.
[0025] 3. By providing an elastic limit member in the present invention, after the valve core moves to abut against the second limit step, the valve core is limited to prevent the valve core from rebounding.
[0026] 4. One end of the valve seat of the present invention is provided with a notch, enabling the valve seat to abut against the support sleeve and be communicated with the lower joint at the same time.
[0027] 5. By providing a first sealing ring in the present invention, the sealing of the first side through-hole by the valve seat is ensured. By providing a second sealing ring and a third sealing ring, the sealing of the internal flow between the upper joint and the lower joint is ensured. By providing a fourth sealing ring, the sealing between the valve seat and the valve core is ensured. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 is a structural schematic diagram of the present invention;
[0029] Figure 2 is a structural schematic diagram of the valve sleeve of the present invention.
[0030] Reference numerals: upper joint 1; first side through-hole 11; lower joint 2; first limiting step 21; second sealing ring 22; second shear member 23; valve seat 3; contact section 31; ventilation section 32; flow-through section 33; second side through-hole 34; ventilation hole 35; second limiting step 36; first sealing ring 37; first shear member 38; notch 39; valve core 4; third side through-hole 41; elastic limiting member 42; third sealing ring 43; fourth sealing ring 44; support sleeve 5; set screw 6; steel ball 7. Detailed implementation manners
[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. 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.
[0032] As Figure 1 shown, the present invention provides an isolation device opened by absolute pressure difference underground, including an upper joint 1, a lower joint 2, a valve seat 3, a valve core 4 and a support sleeve 5. Among them, the upper joint 1, the lower joint 2, the valve seat 3 and the support sleeve 5 are all circular cylindrical structures, and the valve core 4 is a combination of a cylindrical and a circular cylindrical structure.
[0033] The upper joint 1 is provided with a first side through-hole 11. A plurality of first side through-holes 11 are provided, and the plurality of first side through-holes 11 are evenly arranged circumferentially around the upper joint 1. Threads are provided on the inner wall of one end of the upper joint 1.
[0034] One end of the lower joint 2 is inserted into the upper joint 1 and is threadedly connected to the upper joint 1 and fixed by a set screw 6. A first limiting step 21 is provided on the inner wall of the lower joint 2.
[0035] The valve seat 3 is slidably arranged in the upper joint 1. The valve seat 3 is provided with a second side through-hole 34. As Figure 2 shown, a plurality of second side through-holes 34 are provided, and the plurality of second side through-holes 34 are evenly arranged circumferentially around the valve seat 3. As Figure 1 shown, one end of the valve seat 3 closes the first side through-hole 11 of the upper joint 1. A channel is provided between the valve seat 3 and the upper joint 1, so that the second side through-hole 34 is communicated with the inside of the lower joint 2 through the channel. A second limiting step 36 is provided on the inner wall of the valve seat 3;
[0036] The valve core 4 is slidably arranged in the valve seat 3. The end face of the valve core 4 away from the lower joint 2 is conical. A third side through hole 41 is opened on the valve core 4, and the third side through hole 41 is arranged corresponding to the second side through hole 34. That is, the liquid in the upper joint 1 can flow into the lower joint 2 in sequence through the third side through hole 41, the second side through hole 34, and the channel between the valve seat 3 and the upper joint 1; The valve core 4 and the valve seat 3 are connected by a first shear member 38. After the first shear member 38 is cut off, the valve core 4 can axially move to abut against the second limit step 36, so that the third side through hole 41 is not communicated with the second side through hole 34, thereby making the upper joint 1 not communicated with the lower joint 2;
[0037] The support sleeve 5 is slidably arranged at one end of the lower joint 2 inserted into the upper joint 1. The support sleeve 5 abuts against the valve seat 3 and can prevent the valve seat 3 from sliding towards the lower joint 2. The support sleeve 5 and the lower joint 2 are connected by a second shear member 23. The shear strength of the second shear member 23 is greater than that of the first shear member 38. That is to say, after the first shear member 38 is cut off, the second shear member 23 still fixes the support sleeve 5 on the lower joint 2; After the second shear member 23 is cut off, the valve seat 3 can push the support sleeve 5 to move to abut against the first limit step 21, so that the first side through hole 11 is opened.
[0038] Wherein, both the first shear member 38 and the second shear member 23 are shear pins.
[0039] It can be understood that in the initial state, the upper joint 1 is communicated with the lower joint 2 through the third side through hole 41, the second side through hole 34, and the channel between the valve seat 3 and the upper joint 1, and the oil sleeve establishes a circulation; After the first shear member 38 is cut off, the valve core 4 moves to abut against the second limit step 36, the third side through hole 41 and the second side through hole 34 are misaligned, and the passage formed by the third side through hole 41 and the second side through hole 34 is disconnected, so that the oil sleeve is sealed and isolated. At this time, the second shear member 23 is not cut off; After the second shear member 23 is cut off, the valve seat 3 drives the support sleeve 5 to move to abut against the first limit step 21. At this time, the first side through hole 11 is opened, so that the oil pipe is communicated with the formation. This isolation device can realize three functions: oil sleeve connection, oil sleeve isolation, and oil pipe connection with the formation, and has a simple and reliable structure.
[0040] In some embodiments, as Figure 1 shown, a groove is opened on the valve core 4, and an elastic limit member 42 is arranged in the groove. After the valve core 4 axially moves to abut against the second limit step 36, the elastic limit member 42 pops open to limit the rebound of the valve core 4. The elastic limit member 42 can adopt an elastic C-ring.
[0041] It can be understood that when the first shear member 38 is not cut, the valve core 4 fits against the inner wall of the valve seat 3, and the elastic limiting member 42 is squeezed in the groove. After the first shear member 38 is cut, the valve core 4 moves towards the lower joint 2. The inner diameter of the end of the valve seat 3 close to the lower joint 2 is larger than the inner diameter at the position where the first shear member 38 is provided. When the groove moves to the end of the valve seat 3 close to the lower joint 2, the elastic limiting member 42 pops open, which can limit the valve core 4 from moving away from the lower joint 2, thus avoiding the rebound of the valve core 4.
[0042] In some embodiments, as Figure 1 shown, a vent hole 35 is provided on the valve seat 3. The vent hole 35 is close to the second limiting step 36. The vent hole 35 is used to discharge the air between the valve core 4 and the valve seat 3 during the process of the valve core 4 moving axially to contact the second limiting step 36.
[0043] It can be understood that a sealed arrangement is provided between the valve core 4 and the valve seat 3. When the valve core 4 moves relative to the valve seat 3, the air between the end of the valve core 4 and the second limiting step 36 on the valve seat 3 is compressed. By providing the vent hole 35, the air can be discharged through the vent hole 35 into the passage between the valve seat 3 and the upper joint 1, enabling the valve core 4 to smoothly move to abut against the second limiting step 36.
[0044] In some embodiments, the vent hole 35 and the second limiting step 36 are located on the side of the second side through hole 34 away from the lower joint 2.
[0045] As Figure 2 shown, in some embodiments, a plurality of notches 39 are provided at one end of the valve seat 3 close to the lower joint 2. The passage communicates with the inside of the lower joint 2 through the notches 39. By providing the notches 39, the valve seat 3 can both abut against the support sleeve 5 and communicate with the lower joint 2.
[0046] In some embodiments, as Figure 1 、 2 shown, the valve seat 3 includes a contact section 31, a vent section 32, and a flow-through section 33 that are connected in sequence. The outer diameter of the contact section 31 is the largest. The outer diameter of the vent section 32 is smaller than the outer diameter of the contact section 31. The inner diameter of the vent section 32 is equal to the inner diameter of the contact section 31. The outer diameter of the flow-through section 33 is smaller than the outer diameter of the vent section 32. The inner diameter of the flow-through section 33 is smaller than the inner diameter of the vent section 32. The contact section 31 fits against the inner wall of the upper joint 1. The contact section 31 is used to close the first side through hole 11. The vent section 32 does not contact the upper joint 1 or the valve core 4. The second limiting step 36 is arranged at one end of the vent section 32 away from the contact section 31. The flow-through section 33 does not contact the upper joint 1. The inner wall of the flow-through section 33 fits against the valve core 4.
[0047] As Figure 1As shown in the figure, a first sealing ring 37 is provided on the contact section 31 of the valve seat 3. The first sealing ring 37 is arranged on both sides of the first side through hole 11, ensuring the sealing of the first side through hole 11 by the valve seat 3. A second sealing ring 22 is provided between the part of the lower joint 2 inserted into the upper joint 1 and the upper joint 1. A third sealing ring 43 and a fourth sealing ring 44 are provided on the valve core 4. The third sealing ring 43 is arranged on both sides of the third side through hole 41. The second sealing ring 22 and the third sealing ring 43 ensure the sealing of the internal circulation between the upper joint 1 and the lower joint 2. The fourth sealing ring 44 is arranged at one end of the valve core 4 away from the lower joint 2, making the contact section 31 between the valve core 4 and the valve seat 3 sealed.
[0048] The usage method of the downhole absolute pressure difference opened isolation device includes:
[0049] Install the isolation device at the lower end of the tubing to form a tubing string, lower the tubing string. The inside of the upper joint 1 is communicated with the lower joint 2 through the third side through hole 41, the second side through hole 34, and the channel, so as to establish a circulation between the tubing and the casing (i.e., the tubing and the casing).
[0050] After the tubing string reaches the specified depth, drop a steel ball 7 to seat on the valve core 4, blocking the third side through hole 41. Pressurize the tubing until the first shear member 38 is cut off, and the valve core 4 moves to abut against the second limit step 36, making the second side through hole 34 and the third side through hole 41 not communicate, isolating the tubing and the casing.
[0051] After the packer at the upper part of the tubing string is set and the tubing string lowering operation is completed, pressurize the tubing until the second shear member 23 is cut off. The valve seat 3 drives the support sleeve 5 to move to abut against the first limit step 21, and the first side through hole 11 of the upper joint 1 is opened, establishing communication between the tubing and the formation, and starting the acid fracturing transformation.
[0052] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.
Claims
1. An isolation device opened by absolute pressure difference underground, characterized in that Comprising: An upper joint (1) with a first side through-hole (11) formed thereon; A lower joint (2), one end of the lower joint (2) is inserted into the upper joint (1) and fixedly connected to the upper joint (1), and a first limiting step (21) is provided on the inner wall of the lower joint (2); A valve seat (3) slidably arranged in the upper joint (1), with a second side through-hole (34) formed on the valve seat (3). The valve seat (3) closes the first side through-hole (11) of the upper joint (1). A channel is provided between the valve seat (3) and the upper joint (1) such that the second side through-hole (34) communicates with the inside of the lower joint (2) through the channel. A second limiting step (36) is provided on the inner wall of the valve seat (3); A valve core (4) slidably arranged in the valve seat (3), with a third side through-hole (41) formed on the valve core (4). The third side through-hole (41) is arranged corresponding to the second side through-hole (34). The valve core (4) is connected to the valve seat (3) through a first shear member (38). After the first shear member (38) is cut off, the valve core (4) can axially move to abut against the second limiting step (36), so that the third side through-hole (41) is not communicated with the second side through-hole (34); A support sleeve (5) slidably arranged at one end of the lower joint (2) inserted into the upper joint (1). The support sleeve (5) abuts against the valve seat (3). The support sleeve (5) is connected to the lower joint (2) through a second shear member (23). The shear strength of the second shear member (23) is greater than that of the first shear member (38). After the second shear member (23) is cut off, the valve seat (3) can push the support sleeve (5) to move to abut against the first limiting step (21), so that the first side through-hole (11) is opened.
2. The downhole absolute pressure difference-activated isolation device according to claim 1, wherein A groove is formed on the valve core (4), and an elastic limiting member (42) is arranged in the groove. After the valve core (4) axially moves to abut against the second limiting step (36), the elastic limiting member (42) pops open to limit the rebound of the valve core (4).
3. The downhole absolute pressure difference-activated isolation device according to claim 1, wherein A vent hole (35) is formed on the valve seat (3), and the vent hole (35) is close to the second limiting step (36). The vent hole (35) is used to discharge the air between the valve core (4) and the valve seat (3) during the process of the valve core (4) axially moving to abut against the second limiting step (36).
4. The downhole absolute pressure difference-activated isolation device according to claim 3, wherein The vent hole (35) and the second limiting step (36) are located on the side of the second side through-hole (34) away from the lower joint (2).
5. The downhole absolute pressure difference-activated isolation device according to any one of claims 1 to 4, characterized in that, The valve seat (3) includes a contact section (31), a vent section (32) and a flow-through section (33) connected in sequence. The contact section (31) fits against the inner wall of the upper joint (1), and the contact section (31) is used to close the first side through-hole (11). The vent section (32) is not in contact with the upper joint (1) or the valve core (4). The second limiting step (36) is arranged at one end of the vent section (32) away from the contact section (31). The flow-through section (33) is not in contact with the upper joint (1), and the inner wall of the flow-through section (33) fits against the valve core (4).
6. The downhole absolute pressure difference-activated isolation device according to any one of claims 1 to 4, characterized in that, A first sealing ring (37) is arranged on the valve seat (3), and the first sealing ring (37) is disposed on both sides of the first side through hole (11).
7. The downhole absolute pressure difference-activated isolation device according to any one of claims 1 to 4, characterized in that, A second sealing ring (22) is arranged between the part of the lower joint (2) inserted into the upper joint (1) and the upper joint (1).
8. The downhole absolute pressure difference-activated isolation device according to claim 5, characterized in that, A third sealing ring (43) and a fourth sealing ring (44) are arranged on the valve core (4). The third sealing ring (43) is disposed on both sides of the third side through hole (41), and the fourth sealing ring (44) is arranged at one end of the valve core (4) away from the lower joint (2), so as to seal between the contact section (31) of the valve core (4) and the valve seat (3).
9. The downhole absolute pressure difference-activated isolation device according to any one of claims 1 to 4, characterized in that, A plurality of notches (39) are arranged at one end of the valve seat (3) close to the lower joint (2), and the channel communicates with the inside of the lower joint (2) through the notches (39).
10. A method for using an isolation device opened by an absolute downhole pressure difference according to any one of claims 1 to 9, characterized in that, Comprising: Install the isolation device at the lower end of the tubing to form a tubing string, lower the tubing string, and the inside of the upper joint (1) communicates with the lower joint (2) through the third side through hole (41), the second side through hole (34), and the channel, so as to establish a circulation between the tubing and the casing. After the tubing string reaches the designated depth, drop a steel ball (7) to seat on the valve core (4), so that the third side through hole (41) is blocked, and the tubing is pressurized until the first shear member (38) is cut off, and the valve core (4) moves to abut against the second limiting step (36), so that the second side through hole (34) and the third side through hole (41) are not communicated, and the tubing and the casing are isolated. After the packer in the upper part of the tubing string is set and the tubing string lowering operation is completed, the tubing is pressurized until the second shear member (23) is cut off, the valve seat (3) moves with the support sleeve (5) to abut against the first limiting step (21), and the first side through hole (11) of the upper joint (1) is opened, and the tubing communicates with the formation, and acid fracturing reconstruction is started.