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Title:
METHOD OF EXTRACTING GAS FROM TECTONICALLY-DEFORMED COAL SEAM IN-SITU BY DEPRESSURIZING HORIZONTAL WELL CAVITY
Document Type and Number:
WIPO Patent Application WO/2019/205515
Kind Code:
A1
Abstract:
The invention relates to the field of coal seam gas extraction. Disclosed is a method of extracting gas from a tectonically-deformed coal seam in-situ by depressurizing a horizontal well cavity. A horizontal well drilling and reaming subsystem (1, 10) constructs a U-shaped well in which a horizontal well adjoins a vertical well, and performs a reaming process on a horizontal section of the horizontal well (11) to enlarge hole diameter. A horizontal well hole-collapse cavity-construction depressurization excitation subsystem (14, 15, 16) performs pressure-pulse excitation and stress release on the horizontal well of tectonically-deformed coal seam gas, and hydraulically displaces a coal-liquid-gas mixture such that the mixture is conveyed towards a vertical well section along a depressurizing space. A product lifting subsystem (8) further pulverizes the coal and lifts the mixture towards a wellhead of a vertical well (7). A gas-liquid-solid separation subsystem (5, 4) separates the coal, liquid and gas. A monitoring and control subsystem detects and controls the operation conditions and the execution processes of technical equipment in real time. The method enables the completion of a large-diameter horizontal well in a loose tectonically-deformed coal reservoir, horizontal well cavity-constructing stress release, effective lifting of mixed fluids, and efficient separation of produced mixtures, thereby achieving efficient in-situ extraction of tectonically-deformed coal seam gas.

Inventors:
SANG SHUXUN (CN)
LIU SHIQI (CN)
CAO LIWEN (CN)
ZHOU XIAOZHI (CN)
WANG HAIWEN (CN)
LIU HUIHU (CN)
LI ZICHENG (CN)
HUANG HUAZHOU (CN)
LIU CHANGJIANG (CN)
XU HONGJIE (CN)
WANG RAN (CN)
JIA JINLONG (CN)
ZHU SHUYUN (CN)
Application Number:
PCT/CN2018/110864
Publication Date:
October 31, 2019
Filing Date:
October 18, 2018
Export Citation:
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Assignee:
UNIV CHINA MINING (CN)
XUZHOU OLIVINE GEOSCIENCE & GEOTECH CO LTD (CN)
International Classes:
E21B7/04; E21C41/18
Domestic Patent References:
WO2013090979A12013-06-27
Foreign References:
CN102518411A2012-06-27
CN102425397A2012-04-25
CN101775975A2010-07-14
CN104847263A2015-08-19
Attorney, Agent or Firm:
NANJING JINGWEI PATENT & TRADEMARK AGENCY CO., LTD (CN)
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