Method for strengthening flow conductivity of hydraulic fracture of soft coal bed

A technology of hydraulic fractures and flow conductivity, applied in the direction of microorganism-based methods, biochemical equipment and methods, and mining fluids, can solve problems such as poor drainage effects, loose coal quality, and low mechanical strength of coal bodies, and achieve improved Effects of mechanical strength, reduced clogging, and technical ease

Active Publication Date: 2016-09-07
CHONGQING JIAOTONG UNIVERSITY
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  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is mainly to provide a method for strengthening the hydraulic fracture conductivity of soft coal seams for the problem that the soft coal seams are loose in quality and the mechanical strength of coal is low, which leads to the poor effect of hydraulic fracturing technology on the extraction of coalbed methane in soft coal seams.

Method used

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  • Method for strengthening flow conductivity of hydraulic fracture of soft coal bed
  • Method for strengthening flow conductivity of hydraulic fracture of soft coal bed
  • Method for strengthening flow conductivity of hydraulic fracture of soft coal bed

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Use distilled water to prepare the medium required for proliferation culture. The components and concentrations of the medium are peptone 5.0g / L, meat extract 3.0g / L, urea 20.0g / L, MnSO 4 ·H 2 O 10mg / L, the prepared culture medium was sterilized by high-temperature steam at 121°C for 20 minutes, and then placed in a sterile operating table to cool for later use. The purchased strains are in the state of freeze-dried powder, which are stored in vacuum in the ampoule, break the ampoule, inoculate the freeze-dried powder into a triangular flask containing 10mL medium for cultivation, place the triangular flask in the incubator, and transfer it to the triangular flask The formation of bacterial colonies in it indicates that the activation is successful. Inoculate the activated bacterial solution into a Erlenmeyer flask containing 100 mL of medium for proliferation and culture.

[0031] Prepare fixative and gelling solution, the fixative is 0.05mol / L CaCl 2 Solution, gel s...

Embodiment 2

[0037] Example 2 differs from Example 1 in that: (1) the concentration of the fixative solution is 0.06 mol / L, and the concentration of the gelling solution is 1.0 mol / L; (2) the pH of the reservoir mixed solution is 9.0, and the DO value is 3 mg / L , the reservoir temperature is 35°C; (3) The process of injecting the gelling solution is intermittent twice.

[0038] After the reservoir stimulation is completed, check the gas content, extraction concentration, flow rate and permeability coefficient through the inspection holes of the direction and tendency of the coalbed methane reservoir.

Embodiment 3

[0040] Embodiment 3 differs from Example 1 in that: (1) medium components and concentrations are respectively peptone 5.5g / L, meat extract 3.5g / L, urea 22g / L, MnSO 4 ·H 2 O 8~12mg / L; (2) The injection speed of the fixative was 18L / min, and the injection speed of the gelling solution was 1.5L / min. After the injection of the gelling solution, there was an interval of 24 hours. The whole injection process was intermittent for 6 times.

[0041] After the reservoir stimulation is completed, check the gas content, extraction concentration, flow rate and permeability coefficient through the inspection holes of the direction and tendency of the coalbed methane reservoir.

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Abstract

The invention discloses a method for strengthening the flow conductivity of a hydraulic fracture of a soft coal bed. The method includes the following steps that (1) a microbiological culture solution obtained through enrichment culture is injected into a target reservoir stratum via a pressure fracture hole, then a fixing solution is injected into the target reservoir stratum, and a jelling solution is injected intermittently, specifically, the step of intermittently injecting the jelling solution at least comprises one time of the jelling solution injection process and the intermittent process every time after the jelling solution is injected, and microorganisms are Pasteur sporogenes sarcina; and (2) after intermittent injection of the jelling solution is completed, subsequent production is organized according to the downhole hydraulic fracture procedure. By injecting the microorganisms and nutrient substances into the target reservoir stratum and providing full activation, survive and reproduction conditions, calcium carbonate crystals with the jelly property are generated on the hydraulic fracture plane and surrounding coal through the enzyme digestion function of the microorganisms, and accordingly the mechanical strength and the seepage capability of the hydraulic fracture on a gas reservoir of the soft coal bed are improved.

Description

technical field [0001] The invention belongs to the field of underground hydraulic fracturing in coal mines, and in particular relates to a method for strengthening the conductivity of hydraulic cracks in soft coal seams. Background technique [0002] Hydraulic fracturing can promote the extension and connection of primary fractures in the coal seam, provide channels for the migration of coalbed methane, and effectively increase the production of coalbed methane. Hydraulic fracturing is the most widely used reservoir stimulation technology in the surface development of coalbed methane, and it is also a rapidly developing method for increasing permeability and production in the underground drainage of coalbed methane in coal mining areas in my country in recent years. For medium-hard and hard coal seams with relatively simple structure, high mechanical strength, and good fracture conductivity, hydraulic fracturing technology has a good drainage effect, but for soft coal seams...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B43/22C12N1/20C12R1/01
CPCC12N1/20E21B43/16E21B43/26
Inventor 宋晨鹏卢义玉张旋葛兆龙夏彬伟汤积仁贾云中
Owner CHONGQING JIAOTONG UNIVERSITY
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