A coalbed methane liquid co 2 Synergistic fracturing process with active water

A process method and active water technology, which is applied in the field of reservoir stimulation and fracturing of unconventional reservoirs, can solve the problems of high reservoir damage, difficult flowback, and small fracture width in stimulation, and achieve simple and mature technology and comprehensive advantages Obvious, improve the effect of transformation effect

Active Publication Date: 2021-08-06
SOUTHWEST PETROLEUM UNIV
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  • Abstract
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Problems solved by technology

[0004] Although the active water fracturing technology commonly used in coalbed methane has the advantages of low cost, safety, strong operability, and wide application range, it has outstanding disadvantages such as high damage to the reservoir, difficult flowback, and single fracture creation. Make reservoir stimulation less effective
Compared with active water fracturing, liquid carbon dioxide fracturing has many advantages such as high rock-breaking efficiency, complex fracture network, less reservoir damage, easy flowback, and the ability to replace methane in coal seams. Disadvantages such as low pressure in the fracture, small width of the reconstructed fracture, difficulty in carrying and laying proppant, and high cost
If liquid carbon dioxide fracturing is used in the whole process, the construction cost will be increased and the construction risk will be increased

Method used

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  • A coalbed methane liquid co  <sub>2</sub> Synergistic fracturing process with active water

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Embodiment Construction

[0029] The present invention will be described in detail below in conjunction with examples.

[0030] figure 1 A kind of coal bed gas liquid CO of the present invention 2 Flowchart of the co-fracturing process with active water. Such as figure 1 Shown, the inventive method comprises the steps:

[0031] Step S101: Inject nitrogen gas into the casing to displace the liquid in the oil-cassette annulus and maintain the pressure in the oil-cassette annulus.

[0032] Open the reverse circulation valve of the packer first, inject nitrogen gas into the casing, reverse circulation replaces the annulus liquid in the oil sleeve, and close the circulation valve of the packer after the displacement is completed.

[0033] Among them, the liquid in the oil jacket annulus is not resistant to low temperature, and the subsequent injection of liquid CO 2 Sometimes it will solidify and freeze, resulting in a decrease in the external pressure of the oil pipe, causing the risk of damage to th...

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Abstract

The invention provides a coal bed gas liquid CO 2 The cooperating fracturing process with active water includes the following steps: 1) injecting nitrogen into the casing to displace the liquid in the annulus of the oil casing and maintaining the pressure in the annulus of the oil casing; 2) injecting nitrogen into the tubing to clean the fracturing pipeline; 3) injecting nitrogen into the tubing to clean the fracturing pipeline; Injection of liquid CO into the tubing 2 fracturing; 4) injecting nitrogen into the tubing to clean the fracturing pipeline; 5) injecting active water fracturing fluid A into the tubing for fracturing; 6) injecting active water fracturing fluid B into the tubing for fracturing. This method sequentially injects liquid CO 2 Fracturing with active water has the advantages of the two fracturing methods and enhances the effect of fracturing in coal reservoirs.

Description

technical field [0001] The invention relates to a fracturing technology for unconventional reservoirs, in particular to a coal bed gas liquid CO 2 The invention relates to a cooperative fracturing process method with active water, which belongs to the research field of reservoir reconstruction technology. Background technique [0002] Coal bed methane (CBM), also known as coal bed methane, is a kind of unconventional natural gas that is formed during coal formation and occurs in coal seams. Coalbed methane, with methane as the main component, occurs in coal seams in three ways: adsorbed on the coal surface, free in coal pores, and dissolved in coal seam water, most of which (70% to 95%) are adsorbed on the inner surface of coal rock pores superior. Coalbed methane is a very potential unconventional oil and gas resource. Its exploration and development can not only alleviate the national energy shortage, but also help reduce coal mine gas accidents, which has extremely impo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/16E21B43/26
CPCE21B43/164E21B43/166E21B43/26
Inventor 杨兆中李小刚贾敏刘云锐易良平郑昕
Owner SOUTHWEST PETROLEUM UNIV
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