Research and application of pulsating acid fracturing technology in coal seam

doi:10.16265/j.cnki.issn 1003-3033.2020.10.011

Abstract

Abstract: In order to solve permeability problem of coal seams with rich minerals, based on hydraulic fracturing theory and mechanism of permeability enhancement by acid solution dissolving coal minerals, pulsating acid fracturing technology was proposed. Then, acid liquid ratio suitable for Zhongneng coal mine was determined by laboratory permeability test method, and field experiment was carried out. The results show that average mixed flow rate and volume fraction of gas extracted from fracturing hole are 3.10 times and 3.39 times of that of ordinary drainage hole, 1.23 times and 1.28 times of that of pulsating hydraulic fracturing hole, and 2.02 times and 2.04 times of that of ordinary hydraulic fracturing hole. By integrating physical enhancement of fractured coal caused by pulse stress wave and chemical enhancement of acid solution coal, pulsating acid fracturing improves development of fracture-pore space structure, and increases gas diffusion and seepage channel in coal. Meanwhile, carbon dioxide generated by acidifying reaction has a displacement effect on gas, which is conducive to efficient and continuous gas extraction.

Key words: pulsating acid fracturing, permeability enhancement technology, permeability test, acid liquid ratio, pulsating stress wave

CLC Number:

X936

JIA Nan. Research and application of pulsating acid fracturing technology in coal seam[J]. China Safety Science Journal, 2020, 30(10): 75-81.

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