Method for surface modification and transmission increase of coal reservoirs by using chlorine dioxide

A chlorine dioxide and surface modification technology, which is applied in earthwork drilling, gas discharge, and production fluid, can solve the problems of low single well gas production, low gas saturation, and low recovery, and achieve improved pumping The effects of improving recovery efficiency, increasing gas saturation, and increasing permeability

Inactive Publication Date: 2011-08-31
HENAN POLYTECHNIC UNIV
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Problems solved by technology

The reason is that China's coalbed methane has the characteristics of "three lows", that is, low permeability, low gas saturation and low immediate-storage ratio. Although the reservoir stimulation technology adopted is similar to that of foreign countries, the effect is not satisfactory , mainly due to low single well gas production, short stable production period, and low recovery

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Embodiment Construction

[0012] The surface modification and anti-reflection method of chlorine dioxide for coal reservoirs includes the following steps in sequence: (1) Select the proportion of chlorine dioxide according to the coal rank and laboratory tests; (2) Choose to perform hydraulic fracturing storage (3) During the hydraulic fracturing process, the selected concentration of chlorine dioxide is pumped in stages, and the pumping volume in the pre-fluid stage is not less than 70%; ( 4) Fracturing fluid will be drained after 3 hours of shut-in; (5) Effectiveness inspection, the main indicators include the critical desorption pressure, daily gas production and ultimate recovery rate of the CBM well, or the drainage volume of the downhole drilling.

[0013] Said step (1) The level of coal rank determines the concentration of chlorine dioxide used. The basic principle: the chlorine dioxide concentration of weakly caking coal and the following coal rank is 500~1000ppm, and the coal rank chlorine dioxide...

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Abstract

The invention relates to a method for surface modification and transmission increase of coal reservoirs by using chlorine dioxide. The method sequentially comprises the following steps of: (1) selecting the proportioning concentration of the chlorine dioxide according to a coal step and a laboratory experiment; (2) selecting a ground coalbed methane well or an underground drill hole for hydraulic fracturing reservoir modification; (3) pumping chlorine dioxide with selected concentration by stages in the hydraulic fracturing process, wherein the pumping amount in the prepad fluid stage is not less than 70 percent; (4) closing the well for more than 3 hours, and starting to return discharge of a fracturing fluid; and (5) inspecting effects, wherein main indexes comprise critical desorption pressure, daily gas yield and ultimate recovery ratio of the coalbed methane wells or the pumping amount of the underground drill hole. By the method, the daily gas yield and the recovery rate of a single well can be improved, the underground drilling and extraction capability is improved, the extraction efficiency is improved, and the pumping time is shortened.

Description

Technical field [0001] The invention relates to a method for surface modification and penetration enhancement of coal reservoirs by chlorine dioxide. Background technique [0002] The development of coal-bed methane can obtain efficient and clean energy, reduce the cost of coal mine gas treatment, and also reduce greenhouse gas emissions. China has drilled more than 5,000 wells in the eastern margin of the Ordos Basin, Qinshui Basin, Yangquan, Fuxin, Tiefa, Guizhou Liupanshui, Henan Jiaozuo and Anyang (as of the end of 2009), and only some areas have achieved commercial development. The reason is that the occurrence of CBM in China has the characteristics of "three lows", that is, low permeability, low gas saturation and low temporary reserve ratio. Although the technology adopted for reservoir improvement and stimulation is similar to that of foreign countries, the effect is not satisfactory. , Mainly due to the low gas production of a single well, short stable production perio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21F7/00
Inventor 苏现波郭红玉夏大平刘晓宋金星倪小明韩颖蔺海晓陈俊辉
Owner HENAN POLYTECHNIC UNIV
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