Well cementation casing external expansion type packer and using method

Abstract

An opening mechanism and a setting mechanism are installed outside an inner pipe, the lower portion of the opening mechanism is connected with the upper portion of the setting mechanism, a balance hole is formed in the upper portion of the inner pipe and communicated with the inner upper portion of the opening mechanism, the inner pipe is sleeved with a rubber sleeve, the upper portion of the rubber sleeve is connected with the setting mechanism, and the joint is kept sealed. The lower portion of the rubber sleeve is fixed to the outer lower portion of the inner pipe, and the inner wall of the lower portion of the rubber sleeve and the outer wall of the inner pipe are kept sealed. In the well descending process, the opening mechanism and the setting mechanism do not act, well descending, slurry replacement and well cementation cement injection are smoothly carried out, the opening mechanism automatically starts to act after the well cementation cement is replaced, then the setting mechanism works, and a rubber sleeve is expanded for setting. And the procedure of high-pressure pressing and setting is omitted. Well cementation cement cannot be jacked into an oil layer, the oil layer can be prevented from being polluted, the well cementation quality is improved, and cement retention and consolidation accidents of an oil layer section cannot occur in the well cementation process.

Description

Technical Field

[0001] This invention belongs to the field of oilfield well completion engineering technology, specifically relating to an external expansion packer for cementing casing and its usage method. Background Technology

[0002] External packers (OPCs) are essential tools used in cementing operations for oil and gas wells. During oil and gas well drilling, high-pressure, high-temperature oil and gas layers and formation water often exist in the formation, posing significant safety hazards to downhole operations. The function of an external packer is to form a barrier in the annular space between the casing and the wellbore after setting, preventing formation fluids from flowing out of the formation under high pressure through the casing and annular space, thus ensuring the safety of subsequent downhole operations. It also prevents formation fluid leakage, protecting the environment. For oil and gas wells with highly corrosive fluids, it also protects the casing above the packer from corrosion. Especially with the deep development of unconventional oil and gas reservoirs, the application of long horizontal wells is becoming increasingly widespread, and the need for layered development with fracturing and fracturing of long sections and layered sections to prevent inter-layer flow is urgent. Due to their low setting pressure, large annular sealing contact area, and good sealing effect, expansion packers are the mainstream products for cementing casing packers in cementing completions of medium and shallow oil and gas reservoirs, and they adopt an expansion rubber sleeve structure.

[0003] The typical construction procedure for existing external packers is as follows: When the casing is run with a packer, the packer is designed to be located at the top of the oil and gas layer or in the middle of multiple sections. If the well is obstructed during the run-down process, the well is usually flushed by positive circulation. For packers without a pressure-activated control valve, if the circulation pressure is higher than the packer's setting activation pressure, the packer may set prematurely during the run-down process, causing the packer and the entire casing to be obstructed and unable to reach the designed position.

[0004] Positive circulation well washing replaces drilling mud and cleans the annular space between the casing and the well wall; The cementing cement is pumped in through a positive circulation pump, circulating the cementing cement into the annulus between the casing and the wellbore; The sealing plug is inserted, and the positive circulation continues to replace the cement in the casing. When the setting plug touches the shear pin inside the packer, the casing is pressurized and shears the shear pin, opening the setting channel. At this time, if the cement displacement is not smooth, the packer often sets prematurely under pressure, sealing the annulus between the casing and the well wall.

[0005] Because the external packer is located at the top of the casing in the oil and gas reservoir, after the external packer is set, it seals the annulus between the casing and the wellbore. At this time, on the one hand, the cementing cement in the lower part of the external packer and inside the casing is difficult to enter the annulus between the casing and the wellbore through positive circulation, resulting in a large amount of cementing cement remaining in the casing in the oil layer section. After the remaining cement solidifies, it will block the oil layer section, requiring subsequent re-drilling and refining, which involves a large amount of work and high costs. On the other hand, in order to avoid the cementing cement remaining in the casing in the oil layer section, it may be necessary to force this part of the cementing cement into the oil layer through high pressure. The harm of doing so is that the oil layer will be severely contaminated, greatly reducing the connectivity between the formation and the wellbore, which will affect the oil well production in the long term.

[0006] Meanwhile, these packers, which require additional pressure from inside the casing to set the outer packer, are generally set only once. If the tubing moves slightly during the cement consolidation process, the packer may fail to seal properly in different positions or under irregular wellbore conditions. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned problems by designing an external expansion packer for cementing casing and its usage method. This avoids the external expansion packer from setting during the well running process, ensuring the tubing string is smoothly run to the designed position, preventing accidents such as cement residue and consolidation in the casing within the oil layer during cementing, and avoiding the adverse consequences of pushing cement into the oil layer and causing oil layer contamination caused by the need for pressurization to bring the cement to the designed position. This invention enables the external expansion packer for cementing casing to set without pressurization, eliminating the additional pressurization process required for setting.

[0008] The objective of this invention is achieved as follows: It includes an inner tube, a rubber sleeve, an opening mechanism, and a setting mechanism. The opening mechanism and the setting mechanism are installed outside the inner tube. The lower part of the opening mechanism is connected to the upper part of the setting mechanism. The upper part of the inner tube has a balance hole that communicates with the upper inner part of the opening mechanism. The rubber sleeve is fitted outside the inner tube, and the upper part of the rubber sleeve is connected to the setting mechanism, with the connection remaining sealed. The lower part of the rubber sleeve is fixed to the lower outer part of the inner tube, and the inner wall of the lower part of the rubber sleeve remains sealed to the outer wall of the inner tube. During well running, slurry replacement, and cement injection, the pressure inside the casing does not pass through the opening mechanism to the setting mechanism, while the pressure outside the casing can be transmitted to the opening mechanism.

[0009] The opening mechanism includes an inner tube and a hydraulic sleeve. The upper part of the inner tube has a reduced diameter section and an expanded diameter section, with the reduced diameter section above the expanded diameter section. The diameter of the reduced diameter section is smaller than the diameter of the expanded diameter section. The hydraulic sleeve is fitted onto the upper part of the inner tube, with its upper inner part engaging with the reduced diameter section. A seal is placed between the two parts to seal the gap. This seal is located above the balance hole. The lower inner part of the hydraulic sleeve engages with the expanded diameter section, with a seal placed below the balance hole. The reduced diameter section and the interior of the hydraulic sleeve form a connecting cavity, and the balance hole communicates with the connecting cavity.

[0010] The setting mechanism includes an inner tube, a pin, an outer cylinder, and a check valve. The check valve is fixed to the outer wall of the inner tube, and a seal is maintained between the check valve and the inner tube. The outer cylinder is fitted over the check valve, and the lower part of the outer cylinder is connected to the upper part of the rubber tube, with the connection being sealed. The upper part of the outer cylinder is connected to the lower part of the hydraulic sleeve by a pin. The inner wall of the outer cylinder fits with the outer wall of the check valve, and the gap between the two is sealed by a sealing element. An upper cavity and a lower cavity are formed between the inner tube and the outer cylinder. The upper cavity is above the check valve, and the lower cavity is below the check valve. The lower part of the lower cavity communicates with the interior of the rubber tube. The lower part of the hydraulic sleeve extends into the upper part of the upper cavity. The sealing elements between the outer wall of the hydraulic sleeve and the inner wall of the outer cylinder, and between the inner wall of the hydraulic sleeve and the outer wall of the inner tube, seal the upper part of the upper cavity. Liquid in the upper cavity can flow to the lower cavity through the check valve, but liquid in the lower cavity cannot flow into the upper cavity.

[0011] The one-way valve includes a valve seat and a valve body. The valve seat is fixed on the inner tube, and the valve seat and the inner tube are kept sealed. The valve body is placed below the valve seat, and the outer cylinder is fitted on the valve body. There is a sealing element between the inner wall of the outer cylinder and the outer wall of the valve body to seal the gap between them. When the valve seat and the valve body abut against each other, the liquid in the lower cavity cannot flow into the upper cavity.

[0012] There is a spring between the valve body and the rubber sleeve. The spring supports the valve body so that the upper end of the valve body abuts against the lower end of the valve seat.

[0013] The hydraulic sleeve includes a sealing cylinder and a connecting sleeve. The sealing cylinder is fitted onto the upper part of the inner tube. The upper inner part of the sealing cylinder mates with the reduced diameter section, and a seal seals the gap between them. This seal is located above the balance hole. The lower inner part of the sealing cylinder mates with the expanded diameter section, and a seal seals the gap between them. This seal is located below the balance hole. The reduced diameter section and the interior of the sealing cylinder form a connecting cavity, and the balance hole communicates with the connecting cavity. The lower part of the sealing cylinder connects to the upper part of the connecting sleeve. The inner diameter of the connecting sleeve is smaller than the outer diameter of the expanded diameter section, thus restricting the upward movement of the hydraulic sleeve. The lower part of the connecting sleeve extends into the upper part of the upper cavity. The seals between the outer wall of the connecting sleeve and the inner wall of the outer cylinder, and between the inner wall of the connecting sleeve and the outer wall of the inner tube, seal the upper part of the upper cavity. Liquid in the upper cavity can flow to the lower cavity through a check valve, but liquid in the lower cavity cannot flow into the upper cavity.

[0014] The method of use described in this invention is as follows: (1) Downhole operation, grouting, cementing, and top displacement fluid injection The external expansion packer for cementing casing is lowered to the designed position along with the casing. A shut-in valve seat is installed at the bottom of the casing. Cleaning fluid is injected into the casing to replace the slurry, and positive circulation is used to clean the annulus passage between the casing and the wellbore. Then, cementing is injected into the casing, and positive circulation ensures the cementing reaches the annulus passage between the casing and the wellbore. When the injected cement reaches the designed amount, a matching setting plug is inserted into the casing, followed by displacement fluid. The displacement fluid pushes the matching setting plug downwards, and the matching setting plug... When the sealing plug descends to the bottom of the casing, it matches the shut-off valve seat to close the bottom of the casing. The cementing cement cannot return to the casing. At this time, the cementing cement is in the annular channel between the casing and the well wall. When running down the well, replacing the slurry, injecting cementing cement, and applying top displacement fluid, the internal pressure of the expansion packer outside the cementing casing is higher than the external pressure. The rubber sleeve (8) will not expand and seal the annular channel between the casing and the well wall. The annular channel inside the casing and between the casing and the well wall is unobstructed, so that it can smoothly run down the well, replace the slurry, inject cementing cement, and replace cementing cement. (2) Setting of external expansion packer for cementing casing After the bottom of the casing is closed, the injection of displacement fluid into the casing is stopped. The internal pressure of the external expansion packer of the cementing casing is the pressure of the liquid column formed by the displacement fluid, and the external pressure of the external expansion packer of the cementing casing is the pressure of the liquid column formed by the cementing cement. The density of the cementing cement is greater than that of the displacement fluid. The pressure difference formed by the density difference causes the hydraulic sleeve 3 to generate a downward thrust, causing the pin 4 to be sheared. The hydraulic sleeve 3 descends and pushes the liquid in the upper cavity 5-1 downward, causing the check valve 6 to open. The liquid in the upper cavity 5-1 is pushed into the rubber sleeve 8 through the lower cavity 5-2, making the pressure inside the rubber sleeve 8 higher than the external pressure. The rubber sleeve 8 expands, and the external expansion packer of the cementing casing is set. After setting, the check valve is closed. The pressure inside the rubber sleeve 8 is always higher than the external pressure, so that the external expansion packer of the cementing casing is always in the set state.

[0015] The beneficial effects of this invention are as follows: During the running-in, mud replacement (removing the drilling mud), cementing injection, and top-mounting of cementing, the internal pressure of this invention is higher than the external pressure. The rubber sleeve of this invention will not expand and seal the annular channel between the casing and the well wall, ensuring that the tubing string is smoothly run to the designed position. The annular channel inside the casing and between the casing and the well wall is unobstructed, enabling smooth running-in, mud replacement, cementing injection, and top-mounting of cementing. This can prevent accidents such as cement retention and consolidation in the casing in the oil layer section during cementing, and avoid the adverse consequences of pushing cementing into the oil layer and causing oil layer contamination caused by the need for pressurization to drive the cementing to the designed position. This can improve cementing quality. This invention can set the seal without pressurization, eliminating the additional pressurization operation process for setting the seal, and has significant economic benefits. Attached Figure Description

[0016] Figure 1 This is a structural assembly diagram of the present invention.

[0017] Figure 2 yes Figure 1 Assembly diagram of hydraulic sleeve 3.

[0018] Figure 3 yes Figure 1 Structural diagram of the single-flow valve 6. Implementation

[0019] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0020] As shown in the figure, the embodiment of the present invention includes an inner tube 2, a rubber sleeve 8, an opening mechanism, and a setting mechanism. The opening mechanism and the setting mechanism are installed outside the inner tube 2. The lower part of the opening mechanism is connected to the upper part of the setting mechanism. The upper part of the inner tube 2 has a balance hole 2-2, which communicates with the upper inner part of the opening mechanism. The rubber sleeve 8 is fitted outside the inner tube 2. The upper part of the rubber sleeve 8 is connected to the setting mechanism, and the connection is sealed. The lower part of the rubber sleeve 8 is fixed to the lower outer part of the inner tube 2. The inner wall of the lower part of the rubber sleeve 8 is sealed with the outer wall of the inner tube 2. When running into the well, replacing slurry, or injecting cement, the pressure inside the casing does not pass through the opening mechanism to be transmitted to the setting mechanism, while the pressure outside the casing can be transmitted to the opening mechanism.

[0021] As an optimized solution, the opening mechanism includes an inner tube 2 and a hydraulic sleeve 3. The upper part of the inner tube 2 has a reduced diameter section 2-1 and an expanded diameter section 2-3. The reduced diameter section 2-1 is above the expanded diameter section 2-3, and the diameter of the reduced diameter section 2-1 is smaller than the diameter of the expanded diameter section 2-3. The hydraulic sleeve 3 is fitted onto the upper part of the inner tube 2. The upper inner part of the hydraulic sleeve 3 mates with the reduced diameter section 2-1, and a seal is placed between them to seal the gap. This seal is placed above the balance hole 2-2. The lower inner part of the hydraulic sleeve 3 mates with the expanded diameter section 2-3, and a seal is placed between them to seal the gap. This seal is placed below the balance hole 2-2. The reduced diameter section 2-1 and the interior of the hydraulic sleeve 3 form a connecting cavity 3-0, and the balance hole 2-2 communicates with the connecting cavity 3-0.

[0022] As an optimized solution, the setting mechanism includes an inner tube 2, a pin 4, an outer cylinder 5, and a check valve 6. The check valve 6 is fixed to the outer wall of the inner tube 2, maintaining a seal between the check valve 6 and the inner tube 2. The outer cylinder 5 is fitted over the check valve 6, and the lower part of the outer cylinder 5 is connected to the upper part of the rubber sleeve 8, maintaining a seal at the connection. The upper part of the outer cylinder 5 is connected to the lower part of the hydraulic sleeve 3 by the pin 4. The inner wall of the outer cylinder 5 fits with the outer wall of the check valve 6, and the gap between the two is sealed by a sealing element. An upper cavity 5-1 and a lower cavity 5-2 are formed between the inner tube 2 and the outer cylinder 5. The upper cavity 5-1... The lower cavity 5-2 is located above the flow valve 6 and below the flow valve 6. The lower part of the lower cavity 5-2 communicates with the interior of the rubber sleeve 8. The lower part of the hydraulic sleeve 3 extends into the upper part of the upper cavity 5-1. The seal between the outer wall of the hydraulic sleeve 3 and the inner wall of the outer cylinder 5 and the seal between the inner wall of the hydraulic sleeve 3 and the outer wall of the inner tube 2 seal the upper part of the upper cavity 5-1. The liquid in the upper cavity 5-1 can flow to the lower cavity 5-2 through the flow valve 6, but the liquid in the lower cavity 5-2 cannot flow into the upper cavity 5-1.

[0023] As an optimized solution, the one-way valve 6 includes a valve seat 6-1 and a valve body 6-2. The valve seat 6-1 is fixed on the inner tube 2, and the valve seat 6-1 and the inner tube 2 are kept sealed. The valve body 6-2 is placed below the valve seat 6-1, and the outer cylinder 5 is fitted outside the valve body 6-2. There is a sealing element between the inner wall of the outer cylinder 5 and the outer wall of the valve body 6-2 to seal the gap between them. When the valve seat 6-1 and the valve body 6-2 abut against each other, the liquid in the lower cavity 5-2 cannot flow into the upper cavity 5-1.

[0024] As an optimized solution, a spring 7 is provided between the valve body 6-2 and the rubber sleeve 8. The spring 7 supports the valve body 6-2, so that the upper end of the valve body 6-2 abuts against the lower end of the valve seat 6-1.

[0025] As an optimized solution, the hydraulic sleeve 3 includes a sealing cylinder 3-1 and a connecting sleeve 3-2. The sealing cylinder 3-1 is fitted onto the upper part of the inner tube 2. The upper inner part of the sealing cylinder 3-1 mates with the reduced diameter section 2-1, and a seal is placed between them to seal the gap. This seal is positioned above the balance hole 2-2. The lower inner part of the sealing cylinder 3-1 mates with the expanded diameter section 2-3, and a seal is placed between them to seal the gap. This seal is positioned below the balance hole 2-2. The reduced diameter section 2-1 and the interior of the sealing cylinder 3-1 form a connecting cavity 3-0. The balance hole 2-2 and the connecting cavity 3-0... -0 is connected, the lower part of the sealing cylinder 3-1 is connected to the upper part of the connecting sleeve 3-2, the inner diameter of the connecting sleeve 3-2 is smaller than the outer diameter of the expansion section 2-3, which restricts the upward movement of the hydraulic sleeve 3, the lower part of the connecting sleeve 3-2 extends into the upper part of the upper cavity 5-1, the sealing element between the outer wall of the connecting sleeve 3-2 and the inner wall of the outer cylinder 5 and the sealing element between the inner wall of the connecting sleeve 3-2 and the outer wall of the inner tube 2 seal the upper part of the upper cavity 5-1, the liquid in the upper cavity 5-1 can flow to the lower cavity 5-2 through the one-way valve 6, and the liquid in the lower cavity 5-2 cannot flow into the upper cavity 5-1.

[0026] During assembly, the upper cavity 5-1 is filled with liquid (usually hydraulic oil).

[0027] The upper part of the inner tube 2 is connected to the sleeve coupling 1, and the lower part of the inner tube 2 has external sleeve threads, so that the present invention can be connected to the sleeve. If the outer diameter of the inner tube 2 is large, the sleeve internal threads can be machined inside the inner tube 2, so that the sleeve coupling 1 is not needed.

[0028] This invention is connected to the casing and is lowered into the well. During the lowering process, the opening mechanism and the setting mechanism do not operate. After the lowering, grouting, cementing, and cementing replacement are successfully completed, the opening mechanism automatically starts to operate, and then the setting mechanism operates to expand and set the rubber sleeve.

[0029] The method of using this invention is as follows: (1) Downhole operation, grouting, cementing, and top displacement fluid injection The external expansion packer for cementing casing is lowered to the designed position along with the casing. A shut-in valve seat is installed at the bottom of the casing. Cleaning fluid is injected into the casing to replace the slurry, and positive circulation is used to clean the annulus passage between the casing and the wellbore. Then, cementing is injected into the casing, and positive circulation ensures the cementing reaches the annulus passage between the casing and the wellbore. When the injected cement reaches the designed amount, a matching setting plug is inserted into the casing, followed by displacement fluid. The displacement fluid pushes the matching setting plug downwards, and the matching setting plug... When the sealing plug descends to the bottom of the casing, it matches the shut-off valve seat to close the bottom of the casing. The cementing cement cannot return to the casing. At this time, the cementing cement is in the annular channel between the casing and the well wall. When running down the well, replacing the slurry, injecting cementing cement, and applying top displacement fluid, the internal pressure of the expansion packer outside the cementing casing is higher than the external pressure. The rubber sleeve (8) will not expand and seal the annular channel between the casing and the well wall. The annular channel inside the casing and between the casing and the well wall is unobstructed, so that it can smoothly run down the well, replace the slurry, inject cementing cement, and replace cementing cement. (2) Setting of external expansion packer for cementing casing After the bottom of the casing is closed, the injection of displacement fluid into the casing is stopped. The internal pressure of the external expansion packer of the cementing casing is the pressure of the liquid column formed by the displacement fluid, and the external pressure of the external expansion packer of the cementing casing is the pressure of the liquid column formed by the cementing cement. The density of the cementing cement is greater than that of the displacement fluid. The pressure difference formed by the density difference causes the hydraulic sleeve 3 to generate a downward thrust, causing the pin 4 to be sheared. The hydraulic sleeve 3 descends and pushes the liquid in the upper cavity 5-1 downward, causing the check valve 6 to open. The liquid in the upper cavity 5-1 is pushed into the rubber sleeve 8 through the lower cavity 5-2, making the pressure inside the rubber sleeve 8 higher than the external pressure. The rubber sleeve 8 expands, and the external expansion packer of the cementing casing is set. After setting, the check valve is closed. The pressure inside the rubber sleeve 8 is always higher than the external pressure, so that the external expansion packer of the cementing casing is always in the set state. In addition, during the cementing process, the external pressure of the packer is always higher than the internal pressure, which keeps the external expansion packer of the cementing casing in a continuous setting state.

[0030] This invention achieves automatic setting, eliminating the need for high-pressure setting. Because setting can only occur after all cementing cement has been replaced, it prevents accidents such as cement residue and consolidation inside the casing in the oil layer during cementing, and avoids the adverse consequences of pushing cementing cement into the oil layer and causing oil layer contamination, which would otherwise require pressurization to bring the cementing cement to the designed position.

[0031] The pressure difference can be determined by the well depth, displacement fluid density, and cement density. Furthermore, based on the data of the hydraulic sleeve, the reduced diameter section, and the expanded diameter section, the number and diameter of the matching pins can be determined, thereby enabling the automatic setting and sealing of this invention.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A cementing casing external expansion packer, characterized in that: The casing includes an inner tube (2), a rubber sleeve (8), an opening mechanism, and a setting mechanism. The opening mechanism and the setting mechanism are installed outside the inner tube (2). The lower part of the opening mechanism is connected to the upper part of the setting mechanism. The upper part of the inner tube (2) has a balance hole (2-2), which is connected to the upper inner part of the opening mechanism. The rubber sleeve (8) is fitted outside the inner tube (2). The upper part of the rubber sleeve (8) is connected to the setting mechanism, and the connection is sealed. The lower part of the rubber sleeve (8) is fixed to the lower outer part of the inner tube (2). The lower inner wall of the rubber sleeve (8) is sealed to the outer wall of the inner tube (2). When running into the well, replacing the slurry, or injecting cement, the pressure inside the casing does not pass through the opening mechanism to the setting mechanism, but the pressure outside the casing can be transmitted to the opening mechanism.

2. The external expansion packer for cementing casing according to claim 1, characterized in that: The opening mechanism includes an inner tube (2) and a hydraulic sleeve (3). The upper part of the inner tube (2) has a reduced diameter section (2-1) and an expanded diameter section (2-3). The reduced diameter section (2-1) is above the expanded diameter section (2-3). The diameter of the reduced diameter section (2-1) is smaller than the diameter of the expanded diameter section (2-3). The hydraulic sleeve (3) is fitted onto the upper part of the inner tube (2). The upper inner part of the hydraulic sleeve (3) cooperates with the reduced diameter section (2-1). There is a seal between the two to seal the gap between them. This seal is above the balance hole (2-2). The lower inner part of the hydraulic sleeve (3) cooperates with the expanded diameter section (2-3). There is a seal between the two to seal the gap between them. This seal is below the balance hole (2-2). The reduced diameter section (2-1) and the interior of the hydraulic sleeve (3) form a connecting cavity (3-0). The balance hole (2-2) communicates with the connecting cavity (3-0).

3. The external expansion packer for cementing casing according to claim 1, characterized in that: The sealing mechanism includes an inner tube (2), a pin (4), an outer cylinder (5), and a check valve (6). The check valve (6) is fixed on the outer wall of the inner tube (2), and the check valve (6) and the inner tube (2) are sealed together. The outer cylinder (5) is fitted over the check valve (6). The lower part of the outer cylinder (5) is connected to the upper part of the rubber sleeve (8), and the connection is sealed. The upper part of the outer cylinder (5) is connected to the lower part of the hydraulic sleeve (3) by the pin (4). The inner wall of the outer cylinder (5) fits with the outer wall of the check valve (6), and the gap between the two is sealed by a sealing element. An upper cavity (5-1) and a lower cavity (5-2) are formed between the inner tube (2) and the outer cylinder (5). The upper cavity (5-1) The lower cavity (5-2) is located above the flow valve (6) and below the flow valve (6). The lower part of the lower cavity (5-2) is connected to the interior of the rubber sleeve (8). The lower part of the hydraulic sleeve (3) extends into the upper part of the upper cavity (5-1). The seal between the outer wall of the hydraulic sleeve (3) and the inner wall of the outer cylinder (5) and the seal between the inner wall of the hydraulic sleeve (3) and the outer wall of the inner tube (2) seal the upper part of the upper cavity (5-1). The liquid in the upper cavity (5-1) can flow to the lower cavity (5-2) through the flow valve (6). The liquid in the lower cavity (5-2) cannot flow into the upper cavity (5-1).

4. A cementing casing external expansion packer according to claim 3, characterized in that: The one-way valve (6) includes a valve seat (6-1) and a valve body (6-2). The valve seat (6-1) is fixed on the inner tube (2). The valve seat (6-1) and the inner tube (2) are kept sealed. The valve body (6-2) is placed below the valve seat (6-1). The outer cylinder (5) is fitted outside the valve body (6-2). There is a sealing element between the inner wall of the outer cylinder (5) and the outer wall of the valve body (6-2) to seal the gap between them. When the valve seat (6-1) and the valve body (6-2) abut against each other, the liquid in the lower cavity (5-2) cannot flow into the upper cavity (5-1).

5. A cementing casing external expansion packer according to claim 4, characterized in that: There is a spring (7) between the valve body (6-2) and the rubber sleeve (8). The spring (7) supports the valve body (6-2) so that the upper end of the valve body (6-2) abuts against the lower end of the valve seat (6-1).

6. A cementing casing external expansion packer according to claim 2, characterized in that: The hydraulic sleeve (3) includes a sealing cylinder (3-1) and a connecting sleeve (3-2). The sealing cylinder (3-1) is fitted onto the upper part of the inner tube (2). The upper inner part of the sealing cylinder (3-1) mates with the reduced diameter section (2-1), and a seal seals the gap between them. This seal is located above the balance hole (2-2). The lower inner part of the sealing cylinder (3-1) mates with the expanded diameter section (2-3), and a seal seals the gap between them. This seal is located below the balance hole (2-2). The reduced diameter section (2-1) and the interior of the sealing cylinder (3-1) form a connecting cavity (3-0). The balance hole... (2-2) is connected to the connecting cavity (3-0). The lower part of the sealing cylinder (3-1) is connected to the upper part of the connecting sleeve (3-2). The lower part of the connecting sleeve (3-2) extends into the upper part of the upper cavity (5-1). The sealing element between the outer wall of the connecting sleeve (3-2) and the inner wall of the outer cylinder (5) and the sealing element between the inner wall of the connecting sleeve (3-2) and the outer wall of the inner tube (2) seal the upper part of the upper cavity (5-1). The liquid in the upper cavity (5-1) can flow to the lower cavity (5-2) through the one-way valve (6). The liquid in the lower cavity (5-2) cannot flow into the upper cavity (5-1).

7. The method of using the external expansion packer for cementing casing according to any one of claims 1-6, characterized in that, The usage method is as follows: (1) Downhole operation, grouting, cementing, and top displacement fluid injection The external expansion packer for cementing casing is lowered to the designed position along with the casing. A shut-in valve seat is installed at the bottom of the casing. Cleaning fluid is injected into the casing to replace the slurry, and positive circulation is used to clean the annulus passage between the casing and the wellbore. Then, cementing is injected into the casing, and positive circulation ensures the cementing reaches the annulus passage between the casing and the wellbore. When the injected cement reaches the designed amount, a matching setting plug is inserted into the casing, followed by displacement fluid. The displacement fluid pushes the matching setting plug downwards, and the matching setting plug... When the sealing plug descends to the bottom of the casing, it matches the shut-off valve seat to close the bottom of the casing. The cementing cement cannot return to the casing. At this time, the cementing cement is in the annular channel between the casing and the well wall. When running down the well, replacing the slurry, injecting cementing cement, and applying top displacement fluid, the internal pressure of the expansion packer outside the cementing casing is higher than the external pressure. The rubber sleeve (8) will not expand and seal the annular channel between the casing and the well wall. The annular channel inside the casing and between the casing and the well wall is unobstructed, so that it can smoothly run down the well, replace the slurry, inject cementing cement, and replace cementing cement. (2) Setting of external expansion packer for cementing casing After the bottom of the casing is closed, the displacement fluid is stopped being pumped into the casing. The internal pressure of the external expansion packer of the cementing casing is the pressure of the liquid column formed by the displacement fluid, and the external pressure of the external expansion packer of the cementing casing is the pressure of the liquid column formed by the cementing cement. The density of the cementing cement is greater than that of the displacement fluid. The pressure difference formed by the density difference causes the hydraulic sleeve (3) to generate a downward thrust, causing the pin (4) to be sheared. The hydraulic sleeve (3) moves downward and pushes the liquid in the upper cavity (5-1) downward, causing the check valve (6) to open. The liquid in the upper cavity (5-1) is pushed into the rubber sleeve (8) through the lower cavity (5-2), making the pressure inside the rubber sleeve (8) higher than the external pressure. The rubber sleeve (8) expands, and the external expansion packer of the cementing casing is set. After setting, the check valve is closed. The pressure inside the rubber sleeve (8) is always higher than the external pressure, so that the external expansion packer of the cementing casing is always in the set state.

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