CN112901852A - Full-bore shaft pressure-testing soluble toe end valve - Google Patents

Abstract

The invention provides a full-bore shaft pressure-testing soluble toe end valve, wherein a toe end valve body is designed to be full-bore, a plurality of mounting holes penetrating through the pipe wall are arranged on the pipe wall of the body at intervals, and a rupture disc is arranged in each mounting hole. The rupture disc comprises a sealing ring, a soluble material device and a pressing cap, the pressing cap is positioned on one side of the peripheral surface of the body, and the soluble material device is used for blocking the inside and outside communication of the body at the mounting hole; the two ends of the body are connecting ends. The toe end valve of the invention adopts a full-bore design, reduces the outer diameter, is convenient for operation, simultaneously eliminates the influence of well cementation cement, greatly improves the opening success rate, can realize casing high pressure test, has safe and reliable tool performance, simple operation, no failure and controllable soluble material device, and can completely dissolve the soluble material within a certain time after starting, thereby being convenient for subsequent fracturing.

Description

Full-bore shaft pressure-testing soluble toe end valve

Technical Field

The invention relates to a matching tool for oil and gas fracturing well completion, in particular to a soluble toe end valve of a full-drift-diameter shaft capable of testing pressure.

Background

Along with the continuous exploitation of world petroleum resources, oil and gas resources with better reservoir physical properties are less and less; the low-grade oil gas resources with poor reservoir physical properties are becoming the main bodies of oil and natural gas production, the improvement of the single-well yield is the key, the horizontal well becomes an effective means for improving the single-well yield of the low-permeability oil and gas field in recent years, for the horizontal well for well cementation and completion, as no liquid flow channel exists in the first-stage fracturing, a continuous oil pipe or an oil pipe is required to perform perforation operation before fracturing, the process is complex, the period is long, well control risks exist, and the toe end sliding sleeve for the first-stage fracturing of the horizontal well is produced accordingly.

At present, toe end sliding sleeves commonly used at home and abroad generally adopt two structures: firstly, a hydraulic mechanism is arranged, namely, the inner sliding sleeve is displaced under the hydraulic action in a shaft, so that a fracturing port is opened; however, the design structure is complex, the inner diameter of the tool is small, the scraping effect can be ensured only by a specific well cementing rubber plug, and the success rate of later-stage opening is not high due to the influence of cement slurry. The hydraulic mechanism is not adopted, the design that a metal cover plate is additionally arranged outside the blasting valve is adopted, the design structure is simple, the inner diameter of the tool is larger, the influence on the trafficability characteristic of the well cementation rubber plug is smaller, and a specific rubber plug is not needed; due to the existence of the cover plate, annular cement cannot be accumulated outside the explosion valve, and the explosion valve is not influenced to break; but because the apron is the insoluble material, simultaneously, the apron has been accomplished the cement that the cementation was solidified outward to can lead to the blasting valve to break back hydraulic pressure under the hydraulic pressure effect and can't push away the apron, can't form first section fracturing passageway promptly, unable normal fracturing, in addition, this structure can't try high pressure to the sleeve pipe, thereby has increased the fracturing risk to a certain extent.

The conventional fracturing toe end sliding sleeve has low opening success rate due to the influence of factors such as structural reasons, well cementation and the like; the structure is complex, the outer diameter is large, and the inner diameter is small, so that the operation of running a pipe column, cementing and the like is not facilitated; the pressure test of the casing is influenced, and the potential safety hazard of fracturing exists; and when one of the rupture discs fails, the whole toe end sliding sleeve can fail to work, and the working reliability is low.

In order to ensure the purpose of the first-stage fluid channel or the first-stage multi-cluster fracturing construction, a novel efficient and safe toe end valve is designed.

Disclosure of Invention

The invention aims to provide a novel toe end valve structure, wherein the toe end valve adopts a full-bore design, cannot lose efficacy, and a rupture disc system can be partially dissolved in a certain time to form an internal and external passage for communicating the toe end valve, so that subsequent fracturing is facilitated.

In order to achieve the purpose, the invention provides a full-bore shaft pressure-testing soluble toe end valve which is characterized in that a toe end valve body is of a tubular structure with two through ends, and the two ends are connecting ends; a plurality of mounting holes penetrating through the pipe wall are arranged on the pipe wall of the toe end valve body between the two connecting ends at intervals; a rupture disc is arranged in each mounting hole; the rupture disc comprises a pressing cap with a through hole, a soluble material device and a sealing ring; the seal ring is positioned on one side of the inner wall of the toe end valve body, the pressing cap is positioned on one side of the outer peripheral surface of the toe end valve body, and the soluble material device is positioned between the seal ring and the pressing cap; the soluble material device isolates the toe end valve body at the mounting hole and is communicated with the inside and the outside; and after the soluble material device is dissolved, the toe end valve body at the mounting hole is communicated inside and outside.

And protective devices which can be corroded in water are arranged on the two end faces of the soluble material device, which are positioned on the pressing cap and the sealing ring, and the protective devices isolate the soluble material device from contacting liquid.

The protection device is a metal sheet.

The rupture discs are evenly distributed along the circumference of the tube wall of the toe end valve body.

The rupture discs are staggered across different cross-sections of the toe end valve body.

The soluble material device is made of aluminum magnesium alloy material which can be dissolved in water. The material selection range of the soluble material device is wide, the soluble material device can be selected according to different temperatures and mineralization degrees, and the soluble material device is suitable for different well conditions.

A connecting end of the toe end valve body is connected with the outside through internal threads, and the other end of the toe end valve body is connected with the outside through external threads.

The toe end valve body is provided with the inner wall of one end of the internal thread and is provided with the outer peripheral face of the other end of the external thread, and the inner wall and the outer peripheral face are both conical surface structures.

The toe end valve body is a full-bore design structure.

The mounting hole is provided with a limiting step, the sealing ring is arranged on the limiting step, and the pressing cap is fixed in the mounting hole in a threaded connection mode and fixedly compresses the soluble material device.

Compared with the existing toe end sliding sleeve structure, the full-drift diameter shaft soluble toe end valve capable of testing pressure has the advantages of simple structure and convenience in assembly of all parts. Each rupture disc independently sets up respectively in the mounting hole of interval certain distance, and it is mutually independent, does not influence each other, has solved conventional toe end sliding sleeve and has leaded to whole function failure because of single rupture disc goes wrong.

The toe end valve of the invention adopts a full-bore design, reduces the outer diameter, is convenient for operation, simultaneously eliminates the influence of well cementation cement, greatly improves the opening success rate, can realize casing high pressure test, has safe and reliable tool performance, simple operation, no failure and controllable soluble material device, and can completely dissolve the soluble material within a certain time after starting, thereby being convenient for subsequent fracturing.

Drawings

FIG. 1 is a schematic cross-sectional view of a toe end valve body of the present invention.

FIG. 2 is a schematic view of a rupture disc and mounting hole structure at the same cross section.

Detailed Description

For the above technical solutions, reference is now made to fig. 1 to 2 by way of example and specifically described with reference to the drawings, in which:

the full-drift-diameter shaft pressure-testing toe-soluble end valve has the advantages that the toe end valve body 1 is of a tubular structure with a hollow part with two through ends and is designed to be full-drift-diameter, and the inner diameter and the outer diameter of the toe end valve body basically reach the size of a casing. The material is alloy steel material. The two ends of the toe end valve body are connecting ends. The connecting end can be connected with an external part through internal and external threads, and can also be connected with the external part through other connecting devices which can be convenient to seal. In this embodiment, an inner longitudinal button 2 is formed on an inner wall of one end of the toe end valve body as a connection end with an external device, and an outer longitudinal button 3 is formed on an outer circumferential surface of the other end of the toe end valve body as a connection end with the external device. The inner wall of one end of the toe end valve body 1 provided with the long round button 2 and the outer peripheral surface of the toe end valve body 1 provided with the long round button 3 are designed into conical surfaces, and the slopes of the inner conical surface and the outer conical surface of the two ends are the same.

The hollow part from the end provided with the outer long round buckle to the end provided with the inner long round buckle is a cylindrical hollow part structure, and the cylindrical hollow part structure is connected with the inner wall of the end provided with the inner long round buckle through a transition conical surface structure.

A plurality of mounting holes 4 penetrating through the pipe wall of the toe end valve body 1 are arranged on the pipe wall of the toe end valve body 1 between the inner long round buckle and the outer long round buckle at intervals, and a circle of limiting steps are arranged in the mounting holes close to the inner wall of the toe end valve body. The mounting holes are evenly distributed along the circumferential direction of the toe end valve body 1, when the mounting holes are arranged along the length direction and the circumferential direction of the toe end valve body, the mounting holes at the cross section of the same toe end valve body are evenly distributed, and the mounting holes at the cross sections of different toe end valve bodies are distributed in a staggered manner. In this embodiment, the mounting hole of every cross section department is 4, and two adjacent mounting hole contained angles are 90 degrees angles, and the mounting hole distribution of two adjacent different cross sections departments differs by 45 degrees angles.

A rupture disc is mounted within each mounting hole. The rupture disc comprises a sealing ring 5, a soluble material means 6 and a gland 7. Sealing washer 5, in this embodiment, for the sealing washer, places on the spacing step of mounting hole, and sealing washer thickness is no longer than 3 mm. The central part of the sealing ring is provided with a through hole. A soluble material device 6 is placed on the sealing ring, the soluble material device is fixed in the mounting hole 4 through a pressing cap 7, and under the action of the pressing cap 7, the soluble material device presses the sealing ring to realize sealing of a contact surface, so that high-pressure liquid is prevented from being discharged out of the toe end valve in advance through gaps among the parts before the soluble material device is dissolved. The soluble material device 6 is made of a soluble metal material, in this embodiment, a soluble aluminum magnesium alloy material, or other soluble metal materials. In this embodiment, the soluble material device 6 is a cylindrical structure with two concave end faces, or a cylindrical structure without a concave face, or other structures, and the shape of the soluble material device can isolate the communication between the through hole on the press cap and the hollow part of the toe end valve body, and can be dissolved within a certain time. Because one rupture disc corresponds an independent mounting hole, when one rupture disc is invalid, other rupture discs are not influenced, and the working reliability of the toe end valve is ensured.

The pressing cap 7 is of a cap-shaped structure and is made of alloy steel materials. The central part of the end surface of the press cap 7 is provided with a through hole 71. The soluble material device 6 is positioned between the pressing cap 4 and the sealing ring and is fixed by the pressing cap. The soluble material means 6 isolates the communication of the gland 7 with the hollow of the toe end valve body. When the hollow portion of the toe end valve body is filled with liquid and the soluble material device 6 contacts the liquid, it can dissolve within a certain time, so that the hollow portion of the toe end valve body is communicated with the through hole on the press cap, and a channel through which high-pressure liquid flows to the outside of the toe end valve body is formed.

In order to prevent the soluble material device from dissolving in advance, protection devices 8 are provided at both end faces of the soluble material device, respectively. The protection device 8 is made of metal material which can corrode in water. The protective device 8 is a sheet structure, and the diameter of the protective device can cover the through holes on the press cap and the through holes on the sealing ring, so that the liquid is prevented from directly contacting the soluble material device. Through setting up protection device, when using, protection device slowly corrodes under the liquid effect at first, corrodes the perforation when protection device, and liquid can just contact with soluble material device, and soluble material device gets into the dissolution process.

The performance of the machined toe end valve was tested: firstly, a sealing ring, a soluble material device and a pressing cap are sequentially assembled on a toe end valve body, one end of a long round buckle arranged outside is connected with a pressing device, one end of the long round buckle arranged inside is sealed through a pressing plug, and the sealing is checked to be good. And testing the assembled toe end valve, performing step pressurization until the pressure is 70MPa, and stabilizing the pressure for a certain time. The soluble material device dissolves completely within a specified time during the pressing process. I.e., to show that the performance of the toe end valve made in accordance with the present invention meets design goals.

The working principle is as follows: firstly, a sealing ring, a soluble material device, a protection device and a pressure cap are sequentially arranged on a toe end valve body to form a complete toe end valve. The full-drift-diameter shaft pressure-testing soluble toe end valve is connected with the casing through the long round button, and after well drilling and completion, the soluble toe end valve and the casing are connected together and are put into a preset position in a well to complete well cementation;

before fracturing, a sleeve needs to be subjected to pressure test and the toe end valve needs to be opened, the sleeve is pressurized to break the rupture disk with lower pressure, then the pressure is increased to carry out sleeve pressure test, the protective device and the sleeve form a primary battery after the rupture disk is ruptured, the protective device is corroded, after a period of time, the liquid and the soluble material device are contacted and dissolved until the liquid and the soluble material device are completely dissolved, and the through holes in the pressure cap are communicated with the round holes formed in the inner wall of the toe end valve body to form holes. During corrosion of the protection device and dissolution of the soluble material device, casing test high pressures may be performed.

And finally, pressurizing at the wellhead, enabling the liquid to enter the hole of the toe end valve, breaking down the well cementation cement under the action of pressure to enter the stratum, forming a crack channel in the stratum, completing the first-stage fracturing construction of a horizontal well or a vertical well by continuous pumping, and establishing a flow channel for a bridge plug or other processes needing liquid pumping.

In actual use, the toe end valve size will vary depending on the application. The toe end valve is selected to be of an appropriate size based on the size of the mating sleeve. The device for dissolving the materials in the rupture disc selects materials with different dissolving speeds according to different temperature and mineralization requirements and corrosion speeds of the protection device, so that the purpose of bearing pressure can be achieved within a period of time after the protection device is damaged.

Claims (10)

1. A full-bore shaft pressure-testing soluble toe end valve is characterized in that a toe end valve body is of a tubular structure with two through ends, and the two ends are connecting ends; a plurality of mounting holes penetrating through the pipe wall are arranged on the pipe wall of the toe end valve body between the two connecting ends at intervals; a rupture disc is arranged in each mounting hole; the rupture disc comprises a pressing cap with a through hole, a soluble material device and a sealing ring; the seal ring is positioned on one side of the inner wall of the toe end valve body, the pressing cap is positioned on one side of the outer peripheral surface of the toe end valve body, and the soluble material device is positioned between the seal ring and the pressing cap; the soluble material device isolates the toe end valve body at the mounting hole and is communicated with the inside and the outside; and after the soluble material device is dissolved, the toe end valve body at the mounting hole is communicated inside and outside.

2. The full-bore wellbore pressure-testable soluble toe end valve according to claim 1, characterized in that protection devices which can corrode in water are arranged on the two end faces of the soluble material device, located on the pressure cap and the sealing ring, and the protection devices isolate the soluble material device from contacting with liquid.

3. The full-bore wellbore pressure-testable toe-end valve of claim 2, wherein the protective device is a metal sheet.

4. The full-bore wellbore pressure-testable soluble toe valve of claim 1, wherein the rupture discs are evenly distributed along a circumferential direction of a wall of the toe valve body.

5. The full-bore wellbore pressure-testable soluble toe valve of claim 4, characterized in that the rupture disc is staggered across different cross-sections of the toe valve body.

6. The full-bore wellbore pressure-testable soluble toe end valve of claim 1, wherein the soluble material device is a water-soluble aluminum magnesium alloy material.

7. The full-bore wellbore pressure-testable soluble toe end valve of claim 1, characterized in that a connection end of the toe end valve body is connected with the outside through internal threads, and the other end is connected with the outside through external threads.

8. The full-bore wellbore pressure-testable toe-end valve according to claim 1, characterized in that the part provided with the internal thread and the external thread are both conical surface structures.

9. The full-bore wellbore pressure-testable soluble toe valve of claim 1, wherein the toe valve body is a full-bore design structure.

10. The full-bore wellbore pressure-testable soluble toe end valve according to claim 1, characterized in that a limiting step is formed on the mounting hole, the sealing ring is arranged on the limiting step, and the pressure cap is fixed in the mounting hole in a threaded connection manner and fixedly compresses the soluble material device.

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