Underground coal mine hydraulic sand fracturing system and method

Abstract

The invention discloses an underground coal mine hydraulic sand fracturing system and method. The underground coal mine hydraulic sand fracturing system comprises a water supply system, a fluid distribution system, a sand mixing system, a fracturing system and a high-pressure manifold system; the fracturing system is formed by two fracturing pump groups in parallel; the high-pressure manifold system comprises a Y-shaped tee, and two inlet channels of the Y-shaped tee separately communicate with outlets of the two fracturing pump groups; and the fluid distribution system comprises two fluid distribution pools. The fracturing method is implemented based on the fracturing system and comprises the steps that fracturing liquid is prepared by densifiers, crosslinking agents, anti-swelling agents, gel breakers and water according to proportion; the particle size of a supporting agent is 40-70 meshes, and the volume density of ceramsite sand is 1.25g / cm<3>; and fracturing is carried out according to the sequence of first hydraulic fracturing seam generating and later fracturing liquid sand-carrying fracturing support. The underground coal mine hydraulic sand fracturing system has the beneficial effects that the fracturing system is simple in structure and reasonable in layout, and is suitable for sand-carrying fracturing use of underground narrow and small or long and narrow space; andthe fracturing liquid prepared by the fracturing method has suspended sand characteristic, can be suitable for upward drilling sand-carrying fracturing, and has the environmental protection characteristic of being capable of directly discharged.

Description

technical field

[0001] The invention belongs to the field of coal bed gas development, and in particular relates to a coal mine underground hydraulic sand fracturing system and a fracturing method. Background technique

[0002] In the field of coal mines, hydraulic measures represented by hydraulic fracturing are widely used in coal seam permeability enhancement to improve the extraction effect of coal seam gas. With the continuous increase of mining depth in coal mines, the ground stress is getting bigger and bigger. After clear water fracturing is used to increase permeability, under the action of high ground stress, the pressure gap will be closed again. Not only the anti-reflection effect has not been significantly improved, but manpower and material resources are wasted. Therefore, on the basis of clear water fracturing, it is necessary to press proppant into the coal seam gap for support, so as to increase the gas permeability of the coal seam, reduce the attenuation ...

Examples

Embodiment 1

[0050] Example 1, see figure 1 , an underground coal mine hydraulic sand fracturing system, comprising a water supply system, a liquid distribution system, a sand mixing system, a fracturing system and a high-pressure manifold system; the water supply system has pipelines respectively connected to the liquid distribution system and the sand mixing system; The sand mixing system is composed of a sand mixing device 1 and a sand mixing booster device 2. The liquid inlet channel of the sand mixing device 1 is respectively connected with the outlet of the liquid distribution system and the corresponding water supply pipeline of the water supply system through a tee. The mixing of the sand mixing device 1 The liquid outlet port is connected to the inlet port of the supercharging device 2, and the sand mixing device 1 has a proppant adding port for adding proppant; the outlet port of the supercharging device 2 is connected to the fracturing system; the fracturing system consists of tw...

Embodiment 2

[0053] Example 2, combined with figure 1 , a hydraulic sand fracturing method, the method is implemented based on the hydraulic sand fracturing system of embodiment 1, comprising the following steps:

[0054] The first step, fracturing preparation: including hydraulic sand fracturing system layout, fracturing fluid preparation, proppant material preparation, and determining the amount of clean water V according to the fracturing method of clearing water first and then carrying sand in the fracturing fluid 清 , the amount of fracturing fluid V 压 and proppant dosage V 砂 ;

[0055] In the process of fracturing fluid preparation, the fracturing fluid is prepared from thickener, crosslinking agent, anti-swelling agent, gel breaker and water according to the following mass volume ratio and stirred and mixed evenly; the specific preparation ratio is thickened per 100L of water Agent 0.25g, crosslinking agent 0.25g, anti-swelling agent 1.5g, gel breaker 0.15g;

[0056] The proppant...

technical field

[0001] The invention belongs to the field of coal bed gas development, and in particular relates to a coal mine underground hydraulic sand fracturing system and a fracturing method. Background technique

[0002] In the field of coal mines, hydraulic measures represented by hydraulic fracturing are widely used in coal seam permeability enhancement to improve the extraction effect of coal seam gas. With the continuous increase of mining depth in coal mines, the ground stress is getting bigger and bigger. After clear water fracturing is used to increase permeability, under the action of high ground stress, the pressure gap will be closed again. Not only the anti-reflection effect has not been significantly improved, but manpower and material resources are wasted. Therefore, on the basis of clear water fracturing, it is necessary to press proppant into the coal seam gap for support, so as to increase the gas permeability of the coal seam, reduce the attenuation ...

Examples

Embodiment 1

[0050] Example 1, see figure 1 , an underground coal mine hydraulic sand fracturing system, comprising a water supply system, a liquid distribution system, a sand mixing system, a fracturing system and a high-pressure manifold system; the water supply system has pipelines respectively connected to the liquid distribution system and the sand mixing system; The sand mixing system is composed of a sand mixing device 1 and a sand mixing booster device 2. The liquid inlet channel of the sand mixing device 1 is respectively connected with the outlet of the liquid distribution system and the corresponding water supply pipeline of the water supply system through a tee. The mixing of the sand mixing device 1 The liquid outlet port is connected to the inlet port of the supercharging device 2, and the sand mixing device 1 has a proppant adding port for adding proppant; the outlet port of the supercharging device 2 is connected to the fracturing system; the fracturing system consists of tw...

Embodiment 2

[0053] Example 2, combined with figure 1 , a hydraulic sand fracturing method, the method is implemented based on the hydraulic sand fracturing system of embodiment 1, comprising the following steps:

[0054] The first step, fracturing preparation: including hydraulic sand fracturing system layout, fracturing fluid preparation, proppant material preparation, and determining the amount of clean water V according to the fracturing method of clearing water first and then carrying sand in the fracturing fluid 清 , the amount of fracturing fluid V 压 and proppant dosage V 砂 ;

[0055] In the process of fracturing fluid preparation, the fracturing fluid is prepared from thickener, crosslinking agent, anti-swelling agent, gel breaker and water according to the following mass volume ratio and stirred and mixed evenly; the specific preparation ratio is thickened per 100L of water Agent 0.25g, crosslinking agent 0.25g, anti-swelling agent 1.5g, gel breaker 0.15g;

[0056] The proppant...

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