Method of fracturing coal-bed gas reservoir

A coalbed methane and reservoir technology, which is applied in chemical instruments and methods, earthwork drilling, drilling composition and other directions, can solve the problems of difficult flowback, low coalbed methane production, high friction, etc. Low penetration and damage-reducing effects

Active Publication Date: 2017-01-18
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The methods provided by the prior art can not form a long-distance supporting fracture network in the coalbed methane reservoir with the characteristics of "dry coal", and the second is that the friction force between the viscoelastic fracturing fluid and this type of coalbed methane reservoir is large , difficult to reflow
Both of the above factors lead to low coalbed methane production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] The selected coal seam in this embodiment is the Anze block in the Qinnan area of ​​Shanxi. The depth of this coal seam is 800-806 meters, and the thickness is 6 meters. The coal seam roof is argillaceous sandstone, and the depth of the coal seam roof is 795-800 meters. The thickness is 5 meters.

[0059] 1) Perforation: Perforation is carried out in the middle and upper part of the coal seam 4 meters away from the coal seam roof and 3 meters away from the top of the coal seam in the coal seam roof above the coal seam (102 guns, 127 bullets, 60 degree phase angle, and the hole density is 16 holes / m) , the perforation depth is 797-804 meters, the perforation thickness is 7 meters, and the number of perforations is 112.

[0060] 2) Pumping active water fracturing fluid: prepare active water fracturing fluid, which includes the following components in mass percentage: 1.0% KCl, 0.2% clay stabilizer and the balance water. Control the displacement of the active water fracturi...

Embodiment 2

[0067] The selected coal seam in this embodiment is the Zhengzhuang block in Qinnan area, Shanxi. The depth of this coal seam is 1000-1006 meters, and the thickness is 6 meters. The coal seam roof is sandstone. The depth of the coal seam roof is 995-1000 meters, and the thickness is 5 meters.

[0068] 1) Perforation: Perforation is carried out in the middle and upper part of the coal seam 3 meters away from the coal seam roof and in the coal seam roof above the coal seam 3 meters away from the top of the coal seam (102 guns, 127 bullets, 60-degree phase angle, and the hole density is 16 holes / m) , the perforation depth is 997-1003 meters, the perforation thickness is 6 meters, and the number of perforations is 96.

[0069] 2) Pumping active water fracturing fluid: prepare active water fracturing fluid, which includes the following components in mass percentage: 1.5% KCl, 0.3% clay stabilizer and the balance water. Control the displacement of the active water fracturing fluid ...

Embodiment 3

[0076] The selected coal seam in this embodiment is the Anze block in the Qinnan area of ​​Shanxi. The depth of this coal seam is 800-803 meters, and the thickness is 3 meters. The coal seam roof is argillaceous sandstone, and the depth of the coal seam roof is 795-800 meters. The thickness is 5 meters.

[0077] 1) Perforation: Perforation is carried out in the middle and upper part of the coal seam at a distance of 2 meters from the coal seam roof and in the coal seam roof above the coal seam at a distance of 3 meters from the top of the coal seam (102 guns, 127 bullets, 60-degree phase angle, and a hole density of 16 holes / m) , the perforation depth is 797-802 meters, the perforation thickness is 5 meters, and the number of perforations is 80.

[0078] 2) Pumping active water fracturing fluid: prepare active water fracturing fluid, which includes the following components in mass percentage: 1.8% KCl, 0.4% clay stabilizer and the balance water. Control the displacement of th...

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Abstract

The invention discloses a method of fracturing a coal-bed gas reservoir and belongs to the field of coal-bed gas exploitation. The method comprises following steps: after perforation in a middle-upper part of the coal bed and a coal bed top board above the coal bed, active water fracturing fluid is pumped and injected in the coal bed top board to form a first crack; low sand ratio sand-carrying fluid and high sand ratio sand-carrying fluid are successively pumped and injected into the first crack, and a second crack communicated with the first crack is formed in the coal bed, and the extension of the second crack is promoted to form multiple branchlike cracks containing sand support agent. The low sand ratio sand-carrying fluid comprises following components by percentage of mass: 0.1-0.3% carboxymethyl hydroxypropyl guanidine gum, 1-2% KCl, 0.5-1% discharge aiding agent, 8-12% sand support agent, and water as balance; the high sand ratio sand-carrying fluid comprises following components by percentage of mass: 0.1-0.3% carboxymethyl hydroxypropyl guanidine gum, 1-2% KCl, 0.5-1% discharge aiding agent, 12-48% sand support agent, and water as balance. The method provided by the invention can form a long distance supporting seam network in the coal-bed gas reservoir, and effectively improve the yield of the coal-bed gas reservoir.

Description

technical field [0001] The invention relates to the field of coal bed gas exploitation, in particular to a method for fracturing coal bed gas reservoirs. Background technique [0002] my country's coalbed methane development is mainly concentrated in the Qinshui Basin, the Ordos Basin and the Erlian Basin. The coalbed methane reservoirs in these areas (referred to as coalbeds) include shallow coalbed methane reservoirs with a depth of less than 600 meters and middle-deep coalbeds with a depth of more than 600 meters. Coal bed gas reservoir. Among them, the content of medium and deep coalbed methane reservoirs is more than 60%, which generally has the characteristics of "dry coal" such as low porosity, low permeability, and low moisture content. The above-mentioned characteristics of the middle and deep coalbed methane reservoirs lead to low natural productivity, and it is usually necessary to fracturing them to transform the physical structure of the coalbed methane reservoi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B43/267C09K8/68
Inventor 喻鹏杨延辉张洋张永平曲凤娇卫思祺黄晓轩陈伟
Owner PETROCHINA CO LTD
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