Bridge plug integrating plugging and cement plug squeezing and injecting of open hole well section of oil and gas well

Abstract

The invention relates to an oil and gas well open hole section plugging-squeezing cement plug integrated bridge plug which comprises an upper connector, a sealing cylinder, a check valve, a lower core shaft, a rubber cylinder and a round-head sole shoe, the lower portion of the upper connector is connected with the sealing cylinder, the lower core shaft is arranged on the lower portion of the sealing cylinder, a through water hole is formed between the sealing cylinder and the lower core shaft, and the rubber cylinder is connected with the check valve. A check valve is arranged in the lower mandrel and comprises a valve seat and a valve element, the valve seat and the valve element are sealed through a hemispherical sealing face, a valve rod used for righting is arranged at the lower end of the valve element, a baffle is arranged at the lower end of the valve rod, a spring is arranged between the valve element and the baffle, and the lower end of the lower mandrel is connected with a round-head sole shoe. The lower core shaft is sleeved with a rubber sleeve, and a pressure transmitting hole is formed in the lower core shaft. The open hole well section can be plugged, cement plug squeezing and injecting operation can be carried out after bridge plug plugging, and open hole well section plugging and cement plug squeezing and injecting operation can be carried out through one pipe column.

Description

Technical Field

[0001] The present invention relates to the field of oilfield operations, and more particularly to an integrated bridge plug for plugging an open hole section of an oil and gas well and squeezing a cement plug. Background Art

[0002] When the energy of an oil or gas well's producing layer is depleted, a zone-switching operation is often performed. This involves plugging the depleted zone and producing other reservoirs with active oil and gas activity. Currently, the technology for this in-casing zone-switching operation is highly mature, and a wide range of bridge plugs or packers are available for in-casing sealing. However, the openhole bridge plugs required for this operation are complex and demanding on well conditions. If the well deflection exceeds 30°, the success rate of the operation is low. Furthermore, after the bridge plug is sealed, the drill string must be pulled out and a cementing plug string reinserted, making it impossible to complete both the openhole section sealing and cementing operations in a single trip. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plugs, which can complete the plugging of the open hole section of the oil and gas well and the squeezing cement plug operation in one trip of the tubing string.

[0004] The technical solution adopted by the present invention to solve its technical problems is to construct an integrated bridge plug for plugging an open hole section in an oil and gas well and squeezing cement plug, comprising an upper joint, a sealing cylinder, a check valve, a lower core shaft, a rubber sleeve, and a round-head bottom shoe. The lower portion of the upper joint is connected to the sealing cylinder, the lower portion of the sealing cylinder is provided with a lower core shaft, a water hole is provided between the sealing cylinder and the lower core shaft, a check valve is provided inside the lower core shaft, the check valve comprises a valve seat and a valve core, the valve seat and the valve core are sealed by a hemispherical sealing surface, a valve stem for centering is provided at the lower end of the valve core, a baffle is provided at the lower end of the valve stem, a through hole is provided in the center of the baffle, and liquid flow channels are uniformly distributed around the through hole, the valve stem passes through the through hole, a spring is provided between the valve core and the baffle, and the spring is in a compressed state, the lower end of the lower core shaft is connected to the round-head bottom shoe, the outer portion of the lower core shaft is covered with a rubber sleeve, the upper and lower ends of the rubber sleeve are respectively connected to the sealing cylinder and the round-head bottom shoe, and a pressure transmission hole is provided on the lower core shaft.

[0005] In the above solution, the upper end of the upper joint is provided with a thread for connecting to the oil pipe.

[0006] In the above solution, the outer wall of the middle part of the upper joint is provided with a reverse-threaded coarse external thread, and the interior of the sealing cylinder is provided with a reverse-threaded coarse internal thread, and the reverse-threaded coarse internal thread matches the reverse-threaded coarse external thread. In the above solution, a sealing component is provided at the lower end of the reverse thick external thread, and an inner sealing surface is provided at the lower part of the reverse thick internal thread, and the inner sealing surface cooperates with the sealing component to seal. In the above solution, the upper end of the rubber cylinder is threadedly connected to the sealing cylinder and is limited by an "O"-shaped sealing ring and a locking screw.

[0007] In the above solution, the lower end of the rubber cylinder is connected to the round-toe shoe thread, and is sealed and locked by an "O"-shaped sealing ring to limit the screw.

[0008] In the above solution, the pressure transmission hole is located at the lower part of the one-flow valve.

[0009] The present invention also provides an operation method of the oil and gas well open hole section plugging-squeeze cement plug integrated bridge plug, comprising the following steps: S1. Install the integrated bridge plug at the lower end of the delivery string; S2. Lower the integrated bridge plugs in groups to control the liquid level in the water hole to be 500m lower than the annular liquid level.

[0010] S3. After the integrated bridge plug is lowered to the predetermined position, liquid is injected into the oil pipe under pressure. When the pressure reaches 10MPa±, the pump is stopped immediately and the pressure is quickly released to zero. S4. Take the annular space pressure test or annular space liquid filling to measure the liquid level to test the seal. If the seal is not set successfully, repeat the setting steps until the seal is qualified. S5. Lift the pipe string 1-2 tons, rotate the pipe string forward, and if the hanging weight drops suddenly to the original hanging weight, the release is successful. S6. Lift and place the tubing string to the designed position and proceed to the next step according to the cement plug construction design.

[0011] The integrated bridge plug for plugging open hole sections of oil and gas wells and squeezing cement plugs according to the present invention has the following beneficial effects: 1. The present invention has a simple structure, few parts, and a low failure rate. As long as the wellhead can reach the designed well section, the plugging and cementing operations of the open hole section can be carried out, which can improve the reliability of the plugging of the open hole section and ensure that the plugging operation of the open hole section is carried out safely and efficiently.

[0012] 2. The present invention is provided with a one-way valve, which forms a metal seal by cooperating with the hemispherical sealing surface and the valve seat. When it reaches the designed position, the pump can be turned on to perform the pressure-sealing integrated bridge plug operation without throwing the ball, saving the construction time of pumping the steel ball and waiting for the ball to be seated, thereby reducing construction costs. For oil and gas wells with a well inclination greater than 30°, it can effectively solve the problem of uncertainty in the seating of the steel ball. It can also avoid the risk of the coating inside the drilling tool falling off and accumulating in the ordinary ball seat, resulting in the steel ball being unable to seal after seating.

[0013] 3. A spring is interposed between the valve core and the through-hole baffle. During drilling, the spring's elastic potential energy keeps the valve core and valve seat stationary, preventing repeated movement of the valve core and wear on the hemispherical sealing surface and valve seat, thereby ensuring the sealing reliability of the check valve. When the integrated bridge plug is set, the moment the ground pressure is released, the spring's elastic force closes the valve core, thereby sealing the integrated bridge plug, achieving the purpose of blocking the upper and lower strata and effectively ensuring the bridge plug's sealing effect.

[0014] 4. The round-toed bottom shoe provided in the present invention not only prevents the integrated bridge plug from hitting the wellbore diameter change during drilling, thus preventing the integrated bridge plug from encountering resistance, but also reduces the resistance of the integrated bridge plug when passing through irregular and highly inclined open hole sections, thereby increasing the passability of the integrated bridge plug, reducing construction risks, and improving the stability and practicality of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 Schematic diagram of an integrated bridge plug for plugging an open hole section of an oil and gas well and squeezing a cement plug according to the present invention; Figure 2 This is a schematic diagram of the upper joint of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plug according to the present invention; Figure 3 It is a schematic diagram of the sealing cylinder and lower mandrel of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plug according to the present invention; Figure 4 It is a schematic diagram of the valve core of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plug according to the present invention; Figure 5 It is a schematic diagram of the rubber cylinder of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plug according to the present invention; Figure 6 Schematic diagram of the round-toed bottom shoe of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plug according to the present invention; Figure 7 Schematic diagram of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plug during the drilling process of the present invention; Figure 8 It is a schematic diagram of the start-up and setting of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plug according to the present invention; Figure 9 This is a schematic diagram of the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plugs before it is released; Figure 10 Schematic diagram of the integrated bridge plug for plugging open hole section of oil and gas well and squeezing cement plug after release of the present invention; In the figure: 1-upper joint; 1.1-reverse thick external thread; 1.2-sealing assembly; 2-sealing cylinder; 2.1-reverse thick internal thread; 2.2-inner sealing surface; 3-water eye; 4-check valve; 4.1-valve seat; 4.2-valve core; 4.3-valve stem; 4.4-hemispherical sealing surface; 4.5-baffle; 4.6-spring; 4.7-through hole on the baffle; 4.8-liquid flow channel on the baffle; 5-lower core shaft; 6-rubber cylinder; 7-round-head bottom shoe; 8-locking screw; 9-"O" type sealing ring; 10-pressure transmission hole. DETAILED DESCRIPTION

[0016] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0017] like Figure 1-10 As shown, the integrated bridge plug for plugging the open hole section of an oil and gas well and squeezing cement plugs of the present invention comprises an upper joint 1, a sealing cylinder 2, a check valve 4, a lower core shaft 5, a rubber cylinder 6 and a round-head bottom shoe 7.

[0018] The upper end of the upper joint 1 is provided with a female thread of an oil pipe, which can be connected to the oil pipe. The outer wall of the middle part of the upper joint 1 is provided with a reverse-threaded coarse external thread 1.1. The lower end of the reverse-threaded coarse external thread 1.1 is provided with a sealing assembly 1.2. The lower part of the upper joint 1 is connected to a sealing cylinder 2. The interior of the sealing cylinder 2 is provided with a reverse-threaded coarse internal thread 2.1. The reverse-threaded coarse internal thread 2.1 matches the reverse-threaded coarse external thread 1.1. Under the action of external tension, the internal and external threads engage, which can suspend weight and avoid the tool from being pulled back during drilling, thereby improving the safety and practicality of the present invention. After the integrated bridge plug is sealed, the coarse thread is easy to disassemble. After the forward-rotating tubing string is reversed, the cement plug can be squeezed and injected. One trip of the tubing string can achieve the operation of sealing the open hole section and squeezing the cement plug, which greatly improves the progress of on-site construction, reduces the construction workload of pulling in and out drilling tools, and reduces the well control risk caused by frequent drilling.

[0019] An inner sealing surface 2.2 is provided at the lower part of the reverse-threaded coarse internal thread 2.1, and the inner sealing surface 2.2 cooperates with the sealing assembly 1.2 for sealing. A lower core shaft 5 is provided at the lower part of the sealing cylinder 2, and a through water hole 3 is provided between the sealing cylinder 2 and the lower core shaft 5. A one-way valve 4 is provided inside the lower core shaft 5, and the one-way valve 4 is composed of a valve seat 4.1 and a valve core 4.2. The valve seat 4.1 and the valve core 4.2 are sealed by a hemispherical sealing surface 4.4. When it reaches the designed position, the pump can be started to perform the pressure-sealing integrated bridge plug operation without throwing the ball, which saves the construction time of pumping the steel ball and waiting for the ball to be seated, and reduces the construction cost. For oil and gas wells with a well inclination greater than 30°, it can effectively solve the problem of uncertainty in the seating of the steel ball. It can also avoid the risk of the coating inside the drilling tool falling off and accumulating in the ordinary ball seat, resulting in the steel ball being unable to seal after seating.

[0020] A valve stem 4.3 for centering is located at the lower end of valve core 4.2. A baffle 4.5 is located at the lower end of valve stem 4.3. A through-hole 4.7 is defined in the center of baffle 4.5, and two fluid channels 4.8 are evenly distributed around through-hole 4.7. Valve stem 4.3 passes through through-hole 4.7. A spring 4.6 is located between valve core 4.2 and baffle 4.5. Spring 4.6 is compressed. During drilling, the elastic potential energy of spring 4.6 keeps valve core 4.2 and valve seat 4.1 stationary, preventing repeated movement of valve core 4.2 and wear on hemispherical sealing surface 4.4 and valve seat 4.1, thereby ensuring the sealing reliability of check valve 4. When the integrated bridge plug is set and pressure is released from the surface, the elastic force of spring 4.6 closes valve core 4.2, sealing the upper and lower strata and effectively ensuring the plugging effect of the bridge plug.

[0021] The lower end of the lower mandrel 5 is connected to a round-toed bottom shoe 7. This not only prevents the integrated bridge plug from hitting the wellbore diameter change during the drilling process, thus preventing the integrated bridge plug from encountering resistance, but also reduces the resistance of the integrated bridge plug when passing through irregular and highly inclined open hole sections, thereby increasing the passability of the integrated bridge plug, reducing construction risks, and improving the stability and practicality of the present invention.

[0022] The outer portion of the lower core shaft 5 is covered with a rubber tube 6, which is made of high-temperature resistant material and has a large amount of rubber, so that the bridge plug can be used in high-temperature environments; the rubber tube 6 is long and has a large amount of rubber, which can improve the pressure-bearing capacity and sealing ability of the present invention and ensure the normal operation of the present invention.

[0023] The upper and lower ends of the rubber cylinder 6 are respectively threadedly connected to the sealing cylinder 2 and the round-headed bottom shoe 7, and are sealed by an "O"-ring 9 and limited by a locking screw 8. The "O"-ring 9 further ensures that the hydraulic pressure stored in the rubber cylinder 6 cannot leak, thereby improving the stability of the present invention. At the same time, the upper and lower ends of the rubber cylinder 6 are respectively threadedly connected to the sealing cylinder 2 and the round-headed bottom shoe 7, and are limited by the locking screw 8, so that the rubber cylinder 6 as a whole deforms, avoiding local deformation of the rubber cylinder 6 that would cause the rubber cylinder 6 to not fit tightly against the well wall, and preventing uneven force on the integrated bridge plug rubber cylinder 6 from causing process failure, further improving the stability of the present invention.

[0024] A pressure transmission hole 10 is provided on the lower core shaft 5 , and the pressure transmission hole 10 is located at the lower part of the check valve 4 .

[0025] The present invention also provides an operation method of an integrated bridge plug for plugging an open hole section of an oil and gas well and squeezing a cement plug, comprising the following steps: S1. Connect the tool to the lower end of the delivery string on the ground and fix it.

[0026] S2. Assemble the integrated bridge plug according to the pipe string requirements in the construction design. Fill the water holes with liquid every 10 holes. The liquid level in the water holes must be controlled to be 500m lower than the annular liquid level.

[0027] S3. After the bridge plug is lowered to the predetermined position, liquid is injected into the oil pipe under pressure. When the pressure reaches 10MPa±, the pump is stopped immediately and the pressure is quickly released to 0.

[0028] S4. Verify the seal by annular pressure injection or annular fluid injection according to the actual well conditions. If the seal is unsuccessful, repeat the setting steps until the seal is qualified.

[0029] S5. Lift the pipe string 1-2 tons, rotate the pipe string forward, and if the hanging weight drops suddenly to the original hanging weight, the release is successful.

[0030] S6. Lift and place the tubing string to the designed position and proceed to the next step according to the cement plug construction design.

[0031] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. An integrated bridge plug for plugging open hole sections of oil and gas wells and squeezing cement plugs, characterized in that: The cam is provided with a sealing sleeve, a lower core shaft, a water hole is provided between the sealing sleeve and the lower core shaft, and a check valve is provided inside the lower core shaft. The check valve comprises a valve seat and a valve core, and the valve seat and the valve core are sealed by a hemispherical sealing surface. The lower end of the valve core is provided with a valve stem for straightening, and the lower end of the valve stem is provided with a baffle. A through hole is provided in the center of the baffle, and liquid flow channels are evenly distributed around the through hole. The valve stem passes through the through hole, and a spring is provided between the valve core and the baffle, and the spring is in a compressed state. The lower end of the lower core shaft is connected to the round-head bottom shoe, and the outside of the lower core shaft is covered with a rubber sleeve. The upper and lower ends of the rubber sleeve are connected to the sealing sleeve and the round-head bottom shoe respectively, and a pressure transmission hole is provided on the lower core shaft.

2. The integrated bridge plug for plugging open hole section of oil and gas well and squeezing cement plug according to claim 1 is characterized in that: The upper end of the upper joint is provided with a thread for connecting with the oil pipe.

3. The integrated bridge plug for plugging open hole section of oil and gas well and squeezing cement plug according to claim 1 is characterized in that: The outer wall of the middle part of the upper joint is provided with a reverse-threaded coarse external thread, and the interior of the sealing cylinder is provided with a reverse-threaded coarse internal thread, and the reverse-threaded coarse internal thread matches the reverse-threaded coarse external thread.

4. The integrated bridge plug for plugging open hole section of oil and gas well and squeezing cement plug according to claim 3 is characterized in that: A sealing component is provided at the lower end of the reverse-threaded coarse external thread, and an inner sealing surface is provided at the lower part of the reverse-threaded coarse internal thread. The inner sealing surface cooperates with the sealing component for sealing.

5. The integrated bridge plug for plugging open hole section of oil and gas well and squeezing cement plug according to claim 1 is characterized in that: The upper end of the rubber cylinder is threadedly connected to the sealing cylinder and is limited by an "O"-shaped sealing ring and a locking screw.

6. The integrated bridge plug for plugging open hole section of oil and gas well and squeezing cement plug according to claim 1 is characterized in that: The lower end of the rubber cylinder is connected to the round-toe shoe thread and is limited by an "O"-shaped sealing ring and a locking screw.

7. The integrated bridge plug for plugging open hole section of oil and gas well and squeezing cement plug according to claim 1 is characterized in that: The pressure transmission hole is located at the lower part of the check valve.

8. An operating method for an integrated bridge plug for plugging an open hole section of an oil and gas well and squeezing a cement plug according to claim 1, characterized in that: The following steps are involved: S1. Install the integrated bridge plug at the lower end of the delivery string; S2. Lower the integrated bridge plugs in groups to control the liquid level in the water hole to be 500m lower than the annular liquid level.

9. S3. After the integrated bridge plug is lowered to the predetermined position, liquid is injected into the oil pipe under pressure. When the pressure reaches 10 MPa±, the pump is immediately stopped and the pressure is quickly released to zero. S4. Take the annular space pressure test or annular space liquid filling to measure the liquid level to test the seal. If the seal is not set successfully, repeat the setting steps until the seal is qualified. S5. Lift the pipe string 1-2 tons, rotate the pipe string forward, and if the hanging weight drops suddenly to the original hanging weight, the release is successful. S6. Lift and place the tubing string to the designed position and proceed to the next step according to the cement plug construction design.

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