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Multi-stage separate layer fracturing degradable packer and fracturing string

A layered fracturing and packer technology, applied in sealing/isolation, production fluid, wellbore/well components, etc., can solve problems such as sand stuck pipe string, stuck, poor reliability of downhole tools, etc.

Pending Publication Date: 2019-10-01
CNPC BOHAI DRILLING ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, large-scale hydraulic fracturing occupies an extremely important position, but due to the poor reliability of some downhole tools, it is easy to cause downhole accidents in the following situations: When multi-layer fracturing is performed, multi-stage packers and ball seats are usually used Sliding sleeves and sliding sleeves realize the isolation and delamination of intervals. After sand fracturing, sand stuck pipe strings often occur; in double-seal selective fracturing, the bottom packer is often stuck; During fracturing, a packer is usually required to keep the pressure, and the packer is often stuck after being impacted; when a packer tool is inserted into the horizontal section of a horizontal well to search for plugging water, squeeze injection, etc., the packer is often stuck

Method used

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  • Multi-stage separate layer fracturing degradable packer and fracturing string
  • Multi-stage separate layer fracturing degradable packer and fracturing string

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Such as figure 1 As shown, the degradable packer for multi-stage layered fracturing includes a lower joint 22, a slip mechanism, a stepping mechanism, a rubber cartridge mechanism, a piston mechanism and an upper joint that are sequentially fitted on the outside of the central pipe 23 from bottom to top. 1.

[0027] The slip mechanism includes a slip sleeve 15, an upper cone 17, a slip 18, a spring coil 19 and a lower cone 20;

[0028] The lower cone 20 is set on the outside of the central tube 23, its upper inner wall is inwardly recessed and a first annular step is formed, the middle part of its outer wall is provided with a first annular boss, and its upper outer wall is processed so that its outer diameter gradually increases from top to bottom. large cone;

[0029] The upper cone 17 is set on the outside of the central tube 23, and its upper inner wall and lower outer wall are inwardly recessed and formed with a second annular step and a third annular step, and t...

Embodiment 2

[0048] The degradable packer for multi-stage fracturing in this example is further optimized on the materials of each component on the basis of the degradable packer for multi-stage fracturing in Example 1; specifically,

[0049] The central pipe 23 and the upper joint 1 are made of high-strength and non-degradable high-strength alloy steel, which are used to bear the large pressure load during the sealing operation and connect with the fracturing string; the stepping body 12 and the stepping ring 14 Made of tough and non-degradable spring steel; piston pin 5 and slip pin 16 are made of brass;

[0050] The upper supporting rubber cylinder 7, the sealing rubber cylinder 8, the lower supporting rubber cylinder 10, the spring ring 19 and all sealing rings are made of degradable rubber, specifically, the degradable rubber is polyurethane rubber mixed with a certain proportion of carbon black and The outer surface of the rubber material is covered with potassium dihydrogen phosphat...

Embodiment 3

[0054] Further considering the problem that the strength of degradable materials is lower than that of steel, in order to improve the performance of the packer and ensure that the degradable materials will not be damaged under high pressure, the multi-stage layered fracturing in this embodiment The degradable packer further optimizes the size of each part on the basis of the degradable packer for multi-stage layered fracturing in Example 2; specifically,

[0055] The thread on the inner wall of the upper joint 1 is 2-7 / 8"TBG tubing buckle, and its outer diameter is 94mm;

[0056] The outer diameter of the central pipe 23 is 73mm and the inner diameter is 55mm, and four pressure transmission holes with a diameter of 5mm are opened on it to realize the effective transmission of the packer setting pressure; the inner diameter of the central pipe 23 is larger than that of the commonly used All kinds of 5-1 / 2" fracturing packers should have a large inner diameter (46mm), which can ...

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Abstract

The invention discloses a multi-stage separate layer fracturing degradable packer and a fracturing string. The packer comprises a slip mechanism, a stepping mechanism, a rubber sleeve mechanism and apiston mechanism which are sequentially arranged on the outer side of a central pipe in a sleeving mode from bottom to top; slip setting of the slip mechanism is achieved through relative movement ofan upper cone and a lower cone; the piston mechanism located above the rubber sleeve mechanism communicates with an annulus space of the central pipe through a hydraulic hole formed in the central pipe, a rubber sleeve set is driven to be set, and the position of the piston mechanism is locked through the stepping mechanism, and the rubber sleeve mechanism is maintained in the setting state; in addition, all the parts adopt degradable materials and non-degradable materials in a matched mode, so that degradation and unsetting are achieved; and the multi-stage separate layer fracturing degradable packer and a construction string thereof have the characteristics of large diameter, high temperature resistance, high pressure resistance, easy flowback and degradability, and are combined with sliding sleeves to form a fracturing string applicable to deep well and horizontal well fracturing construction, and the problem that existing packers are difficult to get out of shafts after being stuckand buried by sand is effectively solved.

Description

technical field [0001] The invention relates to the technical field of downhole operations in oil and gas fields, in particular to a degradable packer and a fracturing pipe string for multi-stage layered fracturing. Background technique [0002] In the process of oil and gas development, especially when encountering engineering technologies such as development and multi-lateral horizontal wells, large-scale hydraulic fracturing and cluster wells with high density distribution, great environmental pressure will be encountered. The core technology to face such problems is hydraulic fracturing. At present, large-scale hydraulic fracturing occupies an extremely important position, but due to the poor reliability of some downhole tools, it is easy to cause downhole accidents in the following situations: When multi-layer fracturing is performed, multi-stage packers and ball seats are usually used Sliding sleeves and sliding sleeves realize the isolation and delamination of interv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B33/128E21B33/1295E21B43/26E21B34/14
CPCE21B33/1285E21B33/1295E21B34/14E21B43/26
Inventor 张毅任勇强徐克彬陈雅勇张伟李景卫徐昊洋杜鑫芳杨小涛石小龙李俊杰计思宇
Owner CNPC BOHAI DRILLING ENG
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