WO2020237454A1

WO2020237454A1 - Cement retainer

Info

Publication number: WO2020237454A1
Application number: PCT/CN2019/088495
Authority: WO
Inventors: 袁猷; 曾琦军
Original assignee: 成都英诺思科技有限公司
Priority date: 2019-05-27
Filing date: 2019-05-27
Publication date: 2020-12-03

Abstract

A cement retainer, comprising a center pipe (1), a lower connector (6) fixedly connected to one end of the center pipe (1), a sealed anchoring structure sleeved in the circumferential direction of the center pipe (1), a lower connector (6) abutted against one end of the sealed anchoring structure, a push ring (2) provided between the other end of the sealed anchoring structure and the other end of the center pipe (1); check valves (7) respectively provided on either end of the center pipe (1); and, when the check valves (7) are in a connected state, an insertion pipe (8) used for sealed slurry pouring and running through the check valves (7) and a lower connector (6). When the insertion pipe (8) is withdrawn from the cement retainer, all of the check valves (7) switch into a closed state, the interior is then provided with a blind blockage and two-way pressure resistance.

Description

Cement retainer

Technical field

The invention relates to the field of underground petroleum construction, in particular to a cement retainer.

Background technique

In the middle and late stages of oilfield development, due to the corrosion and perforation of the casing above the cement back-up height of the oil well, leakage occurred in the cement cementing section, which caused formation water adjacent to the high-pressure water layer to flow into the wellbore, or the energy of the oil layer decreased. Water-bearing or oil-bearing flooding brings serious difficulties to oilfield development. At present, some old oil wells that have been produced for many years have long-term high water content and are in a shut-in state. Analysis and judgment: First, after long-term exploitation, the oil layer casing may be corroded and perforated, and the casing leakage may cause the oil layer to flood; the second is the high pressure water injection well for long-term high pressure water injection , Forming a head cone with the oil layer of the well and causing the oil layer to flood. The third is that there may be a high-pressure water layer and the oil layer near the oil layer, causing the oil layer to flood. The leak detection of these wells through the packer eliminates the possibility of casing corrosion and perforation loss. Using isotope logging, it was found that there was an adjacent high-pressure water layer in the lower part of the oil layer that channeled each other with the oil layer, so that the well produced all water.

In this case, the conventional treatment method is to first open engineering holes in the high-pressure water layer, and then chemically plug the high-pressure water layer-mainly cement slurry plugging. After the plugging is completed, the cement plug is drilled out, and then the exploitation of the oil layer is resumed. However, the production oil layer of this well is above the high-pressure water layer and is very close to each other. The use of conventional plugging methods not only carries great risks in the construction of the project, but also it is difficult to ensure that the oil layer is not blocked by cement slurry, especially for If the high-pressure water layer is squeezed and blocked, it is possible that the high-pressure water layer will spit out cement slurry, which will make the squeezing failure. Therefore, the only way to separate the oil layer from its adjacent high-pressure water layer is to use a running tool, and then seal the high-pressure water layer.

Cement retainers have been used for many years. Traditional cement retainers are made of metal and run into the well through drill pipes or tubing. Although conventional cement retainers have good sealing performance, high pressure resistance and long sealing time, It can also be milled, but it is easy to cause the liquid to flow back during work and damage the equipment.

Summary of the invention

The technical problem to be solved by the present invention is to provide a cement retainer to ensure that the wellbore is automatically fully sealed again after being blocked, and the wellbore is pressure-bearing in both directions.

The technical solution of the present invention to solve the above technical problems is as follows: a cement retainer, comprising a central pipe and a lower joint fixedly connected to one end of the central pipe, a sealing anchoring structure is sleeved on the circumference of the central pipe, and One end of the sealed anchoring structure abuts against the lower joint, a push ring is arranged between the other end of the sealed anchoring structure and the other end of the central tube; the inner two ends of the central tube are respectively provided with one-way valves , The cut-off directions of the two one-way valves are all toward the middle of the central pipe; when the one-way valve is in the conducting state, the insertion pipe for sealing slurry infusion passes through the one-way valve and the Next connector.

The working principle and beneficial effects of the present invention are as follows: the adapter in the setting tool is fitted and connected to one end of the central tube, and the insertion tube for sealing slurry pouring is inserted into the central tube at the same time, and the lower joint is extended; at this time, two unidirectional The valve is in the unidirectional state, that is, the open state. Lower the cement retainer and its components to the designated position of the wellbore, trigger the setting tool to generate a certain thrust, push the push ring to move downward, and the sealing anchoring structure is tightly anchored to the inner wall of the casing; as a setting tool The provided thrust continues to increase until it is greater than the limit force of the connecting pin between the setting adapter and the center tube, the pin is broken and damaged, the setting and throwing action are completed, and the cement retainer and insertion tube remain at the design setting depth. At this time, the sealing grout is directly injected through the insertion tube. After the sealing grout is completed, the insertion tube is recovered. Since the one-way valve of the cement retainer is in contact with the insertion tube, after the insertion tube leaves the cement retainer, all the one-way valves become closed, and a blind block is formed inside; due to the blocking direction of the two one-way valves All face to the middle of the central pipe; the cement retainer in the lower joint direction can bear the pressure in the lower joint direction because the one-way valve is closed; at the same time, because the one-way valve at the other end of the central pipe is closed, it can Bearing the pressure on the other end of the center tube.

On the basis of the above technical solution, the present invention can also be improved as follows.

Further, the one-way valve includes a valve body and a valve core, the valve core and the valve body are elastically hinged, the valve body is fixedly connected to the inner wall of the central pipe, and the insertion tube passes through the valve body ; When the insertion tube leaves the valve body, the valve core is automatically closed by the elastic hinge.

The beneficial effect of adopting the above-mentioned further solution is that the valve core is automatically closed by the elastic hinge without external driving force, and at the same time, it is very reliable, and the application range of the cement retainer is improved.

Further, the valve body at one end of the central pipe is connected with the central pipe by a fastener to prevent mutual positional displacement.

The beneficial effect of adopting the above-mentioned further scheme is that if the one-way valve and the center pipe are connected by threads, when the cement retainer is drilled and ground, the direction of rotation of the drill bit is opposite to the screwing direction of the thread, so that the one-way valve may move from the center The pipe falls off, causing the one-way valve to remain in the well. The central pipe and the one-way valve are misaligned with each other by means of fasteners. During drilling and grinding, the relative position of the central pipe and the one-way valve will not change. Because the central pipe is fixed to the wellbore by the rivet seal assembly, the drilling During grinding, the one-way valve will not move, ensuring that the one-way valve is completely worn away by the drill and will not remain.

Further, the valve body at the other end of the central pipe is also connected to the central pipe by a fastener to prevent mutual positional displacement.

The beneficial effect of adopting the above-mentioned further solution is that the two one-way valves are completely fixed, which prevents the central pipe and the one-way valve from being misaligned with each other, and further ensures the complete drilling and grinding of the cement retainer.

Further, the one-way valve and the central pipe are connected by screwing.

The beneficial effect of adopting the above-mentioned further solution is that: the threaded screw connection is a reliable connection and fixing method, which is convenient for disassembly and assembly during the assembly test process.

Further, an abutment portion is provided at one end of the lower joint, and the abutment portion abuts against the end of one end of the central tube.

The beneficial effect of adopting the above-mentioned further solution is that by setting the abutment part, when the cement retainer is seated, most of the force of the center tube and the lower joint is located at the abutment part, avoiding the lower joint and the lower joint during the setting process. The fall of the center tube improves the reliability of the sealing of the cement retainer.

Further, the sealing and anchoring structure includes a slip assembly, a cone and a rubber tube, the rubber tube is sleeved in the middle of the central tube; there are two cones, which are located at both ends of the rubber tube and Abut; there are two slip components, one slip component is located between the push ring and one of the cones, and the other slip component is located between the one cone and the lower Between joints.

The beneficial effect of adopting the above-mentioned further solution is that the reliability of anchoring is improved by setting the double slip structure.

Further, the slip assembly includes a slip holder and a slip piece, and the slip piece is nested on the slip holder.

The beneficial effect of adopting the above-mentioned further solution is that the material of the slip seat can be selected flexibly through the anchoring of the slip sheet.

Further, the central tube, the push ring, the cone, the rubber cylinder, the lower joint and the one-way valve are all made of soluble materials.

The beneficial effect of adopting the above-mentioned further solution is that all materials of the cement retainer of the present invention except for the slips are soluble materials, and the soluble materials are completely dissolved in the formation liquid without residues, eliminating the need for drilling and grinding. process.

Description of the drawings

Figure 1 is a cross-sectional view of an open state of a check valve according to an embodiment of the present invention;

2 is a cross-sectional view of the insertion tube inserted into the center tube according to the first embodiment of the present invention;

3 is a cross-sectional view of the closed and cut-off state of the one-way valve according to an embodiment of the present invention;

Figure 4 is a partial view of the slip assembly of the first embodiment.

In the drawings, the list of parts represented by each number is as follows:

1. Center tube, 2. Push ring, 3. Slip component, 4. Cone, 5. Rubber cylinder, 6. Lower joint, 7. One-way valve, 71, Valve body, 72, Spool, 8. Insert tube.

Detailed ways

The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples cited are only used to explain the present invention and not used to limit the scope of the present invention.

Refer to FIG. 1, FIG. 2 and FIG. 3 for the cross-sectional view of the open state of the one-way valve in the first embodiment of the present invention.

A cement retainer includes a central pipe 1 and a lower joint 6 fixedly connected to one end of the central pipe 1, a sealing anchoring structure is sleeved in the circumferential direction of the central pipe 1, and one end of the sealing anchoring structure abuts against the lower joint 6. A push ring 2 is provided between the other end of the sealing anchoring structure and the other end of the central tube 1; the inner two ends of the central tube 1 are respectively provided with one-way valves 7, and the cut-off directions of the two one-way valves 7 are towards the central tube 1. When the one-way valve 7 is in the conducting state, the insertion tube 8 for sealing slurry infusion passes through the one-way valve 7 and the lower joint 6. as shown in picture 2.

The working principle of the present invention is as follows: the adapter in the setting tool is connected to one end of the central tube 1, that is, the adapter is connected to one end of the central tube 11 by a connecting pin, and the insertion tube 8 for sealing slurry is inserted into the central tube 1 at the same time , And extend the lower joint 6; at this time, the two one-way valves 7 are in the unidirectional state, that is, the open state. Lower the cement retainer and its components to the designated position in the wellbore, and trigger the setting tool to generate a certain thrust to push the push ring 2 downward. Because the center pipe 1 and the center pipe 1 are fixedly connected to one end Joint 6, so that the push ring 2 and the lower joint 6 will squeeze the sealing anchoring structure so that the sealing anchoring structure expands and seals the wellbore, and is tightly anchored to the inner wall of the casing; when the setting tool continues to increase the thrust until More than the limit force of the connecting pin between the setting adapter and the central tube 1, the pin is broken and broken, the setting and throwing actions are completed, and the cement retainer and the insertion tube 8 remain at the design setting depth. At this time, the sealing grout is directly injected through the insertion tube 8. After the sealing grout is completed, the insertion tube 8 is recovered. Since the one-way valve 7 of the cement retainer is in contact with the insertion tube 8, after the insertion tube 8 leaves the cement retainer, all the one-way valves 7 become closed and a blind block is formed inside; as shown in 3. Because the cut-off directions of the two one-way valves 7 are towards the middle of the central pipe 1; the cement retainer is in the direction of the lower joint 6 because the one-way valve 7 is closed and cut off, and can bear the pressure in the direction of the lower joint 6; at the same time, because the central pipe The one-way valve 7 at the other end of 1 is in a closed and cut-off state, which can bear the pressure of the other end of the center tube 1.

In this embodiment, the one-way valve 7 includes a valve body 71 and a valve core 72, the valve core 72 and the valve body 71 are elastically hinged, the valve body 71 is fixedly connected to the inner wall of the central tube 1, and the insertion tube 8 passes through the valve body 71; When the insertion tube 8 leaves the valve body 71, the valve core 72 is automatically closed by an elastic hinge. Among them, the elastic hinge may be a torsion spring or the like.

The spool 72 is automatically closed by an elastic hinge, does not require external driving force, is very reliable, and improves the application range of the cement retainer.

In this embodiment, the one-way valve 7 and the central pipe 1 are connected by screwing.

The pattern screw connection is a reliable connection and fixing method, which is easy to disassemble and assemble during the assembly test.

In this embodiment, the valve body 71 at one end of the central pipe 1 is connected to the central pipe 1 by a fastener to prevent mutual positional displacement; the valve body 71 at the other end of the central pipe 1 is also connected to the central pipe 1 by a fastener to prevent mutual displacement. The position is wrong. The fastener in this embodiment is a pin, which is not shown in the figure. A through hole is provided in the radial direction of the center tube 1 and the valve body 71. The pin passes through the through hole, so that the center tube 1 and the valve body 71 are not in position. Dislocation.

Since the one-way valve 7 and the central pipe 1 are connected by threads, when the cement retainer is drilled and ground, the direction of rotation of the drill bit is opposite to the screwing direction, so that the one-way valve 7 may fall off from the central pipe 1, causing The check valve 7 remains in the well. The central pipe 1 and the one-way valve 7 are misaligned with each other by means of fasteners. During drilling and grinding, the relative position of the central pipe 1 and the one-way valve 7 will not change, because the central pipe 1 is fixed to the wellbore by the rivet seal assembly In this way, the one-way valve 7 will not move when drilling and grinding, so as to ensure that the one-way valve 7 is completely worn away by drilling and will not remain.

Regarding the fixed connection method of the one-way valve 7 and the central pipe 1, other connection methods can be selected, for example, the one-way valve 7 is directly embedded in the central pipe 1 through interference fit.

Among them, the positions of the two one-way valves 7 are arranged at both ends of the central pipe. In specific practical application functions, in order to facilitate assembly and construction, the two one-way valves can be set in different positions, as long as the left and right seals are ensured.

The sealing and anchoring structure includes a slip assembly 3, a cone 4, and a rubber tube 5. The rubber tube 5 is sleeved in the middle of the center tube 1; there are two cones 4, which are located at both ends of the rubber tube 5 and abut against it; There are two shoe assemblies 3 in total, one of the slip assemblies 3 is located between the push ring 2 and one of the cones 4, and the other slip assembly 3 is located between the cone 4 and the lower joint 6. Among them, the slip assembly 3 includes a slip holder 31 and a slip piece 32, and the slip piece 32 is nested on the slip holder 31.

By setting the double slip structure, the reliability of anchoring is improved.

The central tube 1, the push ring 2, the cone 4, the rubber cylinder 5, the lower joint 6 and the one-way valve 7 are all made of soluble materials.

All materials of the cement retainer of the present invention except for the slip sheet are soluble materials, and the soluble materials are all dissolved in the formation liquid without residue, and the drilling and grinding process is omitted.

FIG. 4 is a partial view of the slip assembly 3 of the first embodiment. The slip assembly 3 includes a slip holder 31 and a slip piece 32, and the slip piece 32 is nested on the slip holder 31.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. Inside.

Claims

A cement retainer, comprising a central pipe (1) and a lower joint (6) fixedly connected to one end of the central pipe (1), the central pipe (1) is sheathed with a sealing anchoring structure in the circumferential direction, so One end of the sealing anchoring structure abuts against the lower joint (6), and a push ring (2) is provided between the other end of the sealing anchoring structure and the other end of the central tube (1); The central tube (1) is provided with one-way valves (7) at both ends of the central pipe (1), and the cut-off directions of the two one-way valves (7) are both toward the middle of the central pipe (1); When the one-way valve (7) is in a conducting state, an insertion tube for sealing slurry pouring passes through the one-way valve (7) and the lower joint (6).
The cement retainer according to claim 1, wherein the one-way valve (7) comprises a valve body (71) and a valve core (72), the valve core (72) and the valve The body (71) is elastically hinged, the valve body (71) is fixedly connected to the inner wall of the central tube (1), and the insertion tube passes through the valve body (71); when the insertion tube leaves the valve Body (71), the valve core (72) is automatically closed by the elastic hinge.
The cement retainer according to claim 2, characterized in that: the valve body (71) at one end of the central pipe (1) is connected with the central pipe (1) by a fastener to prevent mutual positional displacement .
The cement retainer according to claim 3, characterized in that: the valve body (71) at the other end of the central pipe (1) is also connected to the central pipe (1) by a fastener to prevent mutual position Dislocation.
The cement retainer according to any one of claims 1 to 4, wherein the one-way valve (7) and the central pipe (1) are connected by screwing.
The cement retainer according to any one of claims 1 to 4, characterized in that: one end of the lower joint (6) is provided with an abutment portion, and the abutment portion is connected to the center tube (1). ) Abutting on one end.
The cement retainer according to any one of claims 1 to 4, characterized in that: the sealed anchoring structure comprises a slip component (3), a cone (4) and a rubber cylinder (5), so The rubber tube (5) is sleeved in the middle of the central tube (1); there are two cones (4), which are located at both ends of the rubber tube (5) and abut against it; the slips There are two components (3), one of the slip components (3) is located between the push ring (2) and one of the cones (4), and the other slip component (3) is located in the one Between the cone (4) and the lower joint (6).
The cement retainer according to claim 7, characterized in that: the slip component (3) includes a slip seat (31) and a slip piece (32), and the slip piece (32) is embedded Sleeve on the slip seat (31).
The cement retainer according to claim 8, characterized in that: the central tube (1), the push ring (2), the cone (4), the rubber tube (5), the Both the lower joint (6) and the one-way valve (7) are made of soluble materials.