A small diameter cementing packer

Abstract

The present invention relates to a sealing tool for implementing cementing operation on the top of a screen pipe. It includes a pipe column formed by connecting an upper joint and a central pipe, and an upper fixing sleeve, a rubber tube, a lower fixing sleeve, and a locking ring arranged on the outer wall of the pipe column, wherein: the upper joint is sealed and connected to the top of the central pipe to form an annular cavity; the upper part of the upper fixing sleeve is fixedly connected to the lower end of the upper joint, the lower fixing sleeve is axially locked and positioned on the central pipe by the locking ring, and the rubber tube is clamped on the outside of the central pipe by the upper fixing sleeve and the lower fixing sleeve; a radial through hole is provided on the central pipe, a liquid inlet sealing ring is provided at the radial through hole, an opening ring is fixed on the central pipe below the liquid inlet sealing ring by shear nails, and a guide groove extending to the inside of the rubber tube is provided on the central pipe below the opening ring. The sealing device has a simple structure, high reliability, and small size, and can reduce the risk of cement leakage when cementing the top of the screen pipe is implemented in side drilling wells and small diameter horizontal wells, and achieves the purpose of isolating the screen pipe section and protecting the screen pipe.

Description

Technical Field

[0001] The invention relates to the field of well completion tools, in particular to an isolation tool for implementing a screen pipe top cementing operation. Technical Background

[0002] When cementing the top of the screen during conventional side drilling or small diameter horizontal well completion, due to the limitation of experience size, only cement umbrella can be used as a tool to isolate the screen section. When the formation fracture pressure is low or the ground is prone to leakage, the cement umbrella is difficult to completely isolate the screen section, which is very likely to cause leakage and block the screen, affecting the subsequent production. Summary of the invention

[0003] The purpose of the present invention is to address the problems existing in the prior art and provide a small-diameter cementing packer with a compact structure and small size that can be applied to side-drilling wells or small-diameter horizontal wells, thereby more effectively isolating the screen section and reducing the occurrence of cement leakage and screen blockage.

[0004] The technical solution of the present invention includes:

[0005] A small-diameter cementing packer comprises a pipe column formed by connecting an upper joint and a center pipe, and an upper fixing sleeve, a rubber sleeve, a lower fixing sleeve and a locking ring arranged on the outer wall of the pipe column, wherein: after the upper joint is sealed and connected to the top of the center pipe, the lower part of the upper joint and the upper part of the center pipe form an annular cavity; the upper part of the upper fixing sleeve is fixedly connected to the lower end of the upper joint, the lower fixing sleeve is axially locked and positioned by a locking ring threadedly connected to the lower part of the center pipe, and the upper and lower ends of the rubber sleeve are respectively clamped on the outside of the center pipe by the upper fixing sleeve and the lower fixing sleeve; a radial through hole is provided on the center pipe in the upper section of the annular cavity, and a liquid inlet sealing ring that cooperates with the radial through hole in a one-way seal is provided in the annular cavity outside the radial through hole; an opening ring is fixed on the center pipe below the liquid inlet sealing ring by shear nails, and the inner and outer walls of the opening ring respectively form an axial sliding sealing cooperation with the center pipe and the upper joint, and a guide groove is provided on the outer wall of the center pipe below the opening ring, which extends downward all the way to the inside of the rubber sleeve; the liquid inlet sealing ring is made of elastic material.

[0006] The above scheme further comprises:

[0007] A pier section is provided on the central tube at the lower part of the annular cavity. The outside of the pier section is sealed and fixedly connected to the upper joint and the upper fixing sleeve by pins. The inside of the pier section is provided with a guide channel connected to the guide groove, and the guide groove extends to the inside of the rubber cylinder through the guide channel.

[0008] The liquid inlet sealing ring is a cone structure.

[0009] A threaded joint is provided at the lower end of the central tube.

[0010] Another small-diameter cementing packer includes a pipe column composed of an upper joint and a center pipe, and an upper fixing sleeve, a rubber tube, a lower fixing sleeve, and a locking ring arranged on the outer wall of the pipe column, wherein: after the upper joint is sealed and connected to the top of the center pipe, the lower part of the upper joint and the upper part of the center pipe form an annular cavity; the upper part of the upper fixing sleeve is fixedly connected to the lower end of the upper joint, and the lower fixing sleeve is axially locked and positioned by a locking ring threadedly connected to the lower part of the center pipe, and the upper and lower ends of the rubber tube are respectively clamped on the outside of the center pipe by the upper fixing sleeve and the lower fixing sleeve; a radial through hole is provided on the center pipe in the upper section of the annular cavity, and a one-way valve is provided at the radial through hole, and a guide groove or a guide channel is provided on the outer wall of the center pipe below the radial through hole, and the guide groove or the guide channel extends downward all the way to the inside of the rubber tube.

[0011] A threaded joint is provided at the lower end of the central tube.

[0012] The present invention designs a small-diameter cementing packer in combination with the borehole size conditions of small-sized horizontal wells and side-drilled wells. The packer can isolate the screen section of small-sized horizontal wells and side-drilled wells under the condition of ensuring that the inner diameter is consistent with the completion casing and the screen. Compared with the cement umbrella, it has a better isolation effect and can reduce the probability of cement leakage during cementing. The tool has a simple structure, high reliability, and small size. It can be used in side-drilled wells and small-diameter horizontal wells with limited wellbore space. Compared with the cement umbrella, it has the advantage of strong isolation ability, can reduce the risk of cement leakage when cementing the top of the screen in side-drilled wells and small-diameter horizontal wells, prevent cement from entering the screen section, and achieve the purpose of isolating the screen section and protecting the screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of a small-diameter cementing packer. DETAILED DESCRIPTION

[0014] The present invention is described in detail below with reference to the accompanying drawings.

[0015] Example 1.

[0016] Combined with Figure 1 The present embodiment mainly consists of an upper joint 1, a sealing member 2, a liquid inlet sealing ring 3, a center tube 4, an opening ring 5, a pin 6, an upper fixing sleeve 7, a rubber tube 8, a lower fixing sleeve 9, and a locking ring 10. A liquid inlet hole 11 is opened on the center tube 4, and a tool inner cavity 12 (equivalent to a guide groove or a guide channel) is formed between the center tube 4 and the rubber tube 8.

[0017] Among them: the upper joint 1 has threads, which mainly serves the function of connecting the upper tool. The upper joint 1 and the center tube 4 are fixed by a pin 6 (it can also be fixed by the threaded connection on the top of the center tube). The upper joint 1 and the center tube 4 are sealed by a seal 2. A radial liquid inlet hole 11 is reserved on the upper part of the center tube 4. The liquid inlet sealing ring 3 is located on the liquid inlet hole 11 of the center tube 4. The opening ring 5 is located in the annular cavity between the center tube 4 and the upper joint 1 at the lower part of the liquid inlet sealing ring 3. The opening ring 5 is fixed to the center tube 4 (or the upper joint) by shear nails. The upper fixing sleeve 7 is located on the outer side of the upper part of the rubber cylinder 8, and plays a role in fixing the upper part of the rubber cylinder 8. The lower fixing sleeve 9 is located on the outer side of the lower part of the rubber cylinder 8, and plays a role in fixing the lower part of the rubber cylinder 8. The locking ring 10 is located at the lower part of the rubber cylinder 8 and the lower fixing sleeve 9, and plays a role in fixing and limiting. The locking ring 10 is fixed to the center tube 4 by threads.

[0018] Furthermore, the liquid inlet sealing ring 3 is a cone structure made of elastic material (such as rubber).

[0019] Furthermore, a pier section is provided on the central tube 4 at the lower part of the annular cavity, and the outside of the pier section is sealed and fixedly connected to the upper joint 1 and the upper fixed sleeve 7 by a pin 6. The inside of the pier section is provided with a guide channel connected to the guide groove, and the guide groove extends to the inside of the rubber cylinder 8 through the guide channel.

[0020] How the tool works:

[0021] The fluid inlet control of the tool is controlled by the opening ring and the fluid inlet sealing ring. The function of the opening ring is to limit the opening of the tool. The opening ring is fixed on the central pipe by shear pins. During the lowering of the tool, the opening ring seals the fluid inlet channel to prevent the fluid in the pipe column from entering the inner cavity of the tool and causing the packer to open accidentally. After the tool is in place, pressurize it. When the pressure in the pipe reaches the shear pin set pressure, the shear pin is cut off, and the opening ring is lowered to leak out of the fluid inlet channel on the central pipe. After that, the tool can be normally filled with fluid.

[0022] The function of the liquid inlet sealing ring is to limit the outflow of the liquid filled in the tool. The material of the liquid inlet sealing ring can be rubber. When the pressure in the pipe column is higher than the pressure in the tool cavity, the liquid can squeeze the liquid inlet sealing ring and enter the tool cavity. When the pressure in the pipe column is relieved and the pressure in the tool cavity is higher than the pressure in the pipe column, the liquid in the tool cavity will squeeze the liquid inlet sealing ring to seal the liquid inlet hole of the center pipe and prevent the liquid filled in the tool from flowing out, thereby achieving the purpose of ensuring the continuous expansion and sealing of the tool.

[0023] Example 2.

[0024] See attached Figure 1A small diameter cementing packer, comprising a pipe string formed by connecting an upper joint 1 and a center pipe 4, and an upper fixing sleeve 7, a rubber sleeve 8, a lower fixing sleeve 9, and a locking ring 10 arranged on the outer wall of the pipe string, wherein: after the upper joint 1 is sealed and connected to the top of the center pipe 4, the lower part of the upper joint 1 and the upper part of the center pipe 4 form an annular cavity; the upper part of the upper fixing sleeve 7 is fixedly connected to the lower end of the upper joint 1 and the center pipe 4 through a pin 6, and the lower fixing sleeve 9 is axially locked and positioned by a locking ring 10 threadedly connected to the lower part of the center pipe, and the upper and lower ends of the rubber sleeve 8 are clamped on the outside of the center pipe 4 by the upper fixing sleeve 7 and the lower fixing sleeve 9 respectively; a radial through hole is provided on the center pipe 4 in the upper section of the annular cavity, and a one-way valve (replacing the liquid inlet sealing ring 3 and the opening ring 5 in embodiment 1) is provided at the radial through hole, and a guide groove or a guide channel is provided on the outer wall of the center pipe 4 below the radial through hole, and the guide groove or the guide channel extends downward to the inside of the rubber sleeve 8.

[0025] A threaded joint is provided at the lower end of the central tube.

[0026] The specific working mode of the tool is as follows: the inside of the tubing is pressurized, the liquid opens the one-way valve, the hydraulic pressure acts on the rubber cylinder to achieve the expansion and sealing of the tool, and then the pressure in the tubing is released. When the pressure in the tool cavity is higher than the pressure in the tubing, the one-way valve closes to prevent the liquid in the tool cavity from flowing out, thereby achieving continuous expansion and sealing of the packer.

Claims

1. A small diameter cementing packer, comprising a pipe string formed by connecting an upper joint and a central pipe, and an upper fixing sleeve, a rubber sleeve, a lower fixing sleeve, and a locking ring arranged on the outer wall of the pipe string, characterized in that: After the upper joint is sealed and connected to the top of the center tube, the lower part of the upper joint and the upper part of the center tube form an annular cavity; the upper part of the upper fixing sleeve is fixedly connected to the lower end of the upper joint, and the lower fixing sleeve is axially locked and positioned by a locking ring threadedly connected to the lower part of the center tube, and the upper and lower ends of the rubber cylinder are clamped on the outside of the center tube by the upper fixing sleeve and the lower fixing sleeve respectively; a radial through hole is provided on the center tube in the upper section of the annular cavity, and a liquid inlet sealing ring that cooperates with the radial through hole in a one-way seal is provided in the annular cavity outside the radial through hole, and a through hole is provided on the center tube below the liquid inlet sealing ring. An opening ring is fixed by the shear pins, and the inner and outer walls of the opening ring respectively form an axial sliding seal with the center tube and the upper joint. A guide groove is provided on the outer wall of the center tube below the opening ring, and the guide groove extends downward to the inside of the rubber tube; the liquid inlet sealing ring is made of elastic material; a pier section is provided on the center tube at the lower part of the annular cavity, and the outside of the pier section is sealed and fixedly connected with the upper joint and the upper fixed sleeve by pins, and a guide channel connected with the guide groove is provided inside the pier section, and the guide groove extends to the inside of the rubber tube through the guide channel; the liquid inlet sealing ring is a cone structure.

2. A small diameter cementing packer according to claim 1, characterized in that: A threaded joint is provided at the lower end of the central tube.

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