公开(公告)号：US20190145259A1

公开(公告)日：2019-05-16

申请号：US16097828

申请日：2017-12-01

Applicant: China University of Mining and Technology

Inventor： Baiquan LIN ,  Tong LIU ,  Ting LIU ,  Wei YANG ,  He LI ,  Zhanbo HUANG ,  Rui WANG ,  Yihan WANG

IPC: E21F7/00

CPC classification number: E21F7/00

Abstract: A method for stepwise construction of a preferential gas migration pathway at a stope in a coal seam. First, a gas migration pathway is preliminarily formed at a stope depending on a mining effect of mining in a first mined seam. construction and stabilization method of gob-side entry retaining in deep strata, and a method of manual-guided pre-fracturing boreholes are then used to perform active construction respectively in external space and the outside of coal-rock mass to form preferential gas migration pathways. Eventually, under the effect of mining-induced stress, a system of preferential gas migration pathways connected to each other at the stope is further formed.

公开(公告)号：US20240110465A1

公开(公告)日：2024-04-04

申请号：US18027605

申请日：2021-12-27

Applicant: CHINA UNIVERSITY OF MINING AND TECHNOLOGY

Inventor： WEI YANG ,  ZENING WEI ,  CHENG ZHAI ,  Yihan WANG ,  WENYUAN WANG ,  WENXIAO ZHANG

IPC: E21B43/00 ,  E21B34/06 ,  E21B43/1185 ,  E21B43/248 ,  E21B43/263 ,  E21B49/00 ,  G01N33/00

CPC classification number: E21B43/006 ,  E21B34/066 ,  E21B43/1185 ,  E21B43/248 ,  E21B43/263 ,  E21B49/00 ,  G01N33/0027 ,  E21B7/046

Abstract: A method for shale gas exploitation includes performing horizontal drilling operation on an area to be constructed, forming a crack around a horizontal drill hole wall by shaped charge perforation; expanding the crack around a horizontal hole hydraulic fracturing, and extracting methane gas after a fracturing fluid is discharged; after methane gas is reduced, performing in-situ combustion explosion fracturing on the methane involved in horizontal drilling; thereafter continuing to expand the crack in the horizontal drill hole such that methane continues to seep out, and continuing extracting methane; repeating combustion explosion fracturing and extraction operations, so as to increase combustion explosion cracking permeability, and greatly enhance the exploitation effect of shale gas. The method is suitable for fracturing reconstruction of unconventional oil and gas reservoirs such as shale gas reservoirs, coal seam gas reservoirs and tight sandstone gas reservoirs.

公开(公告)号：US20200240245A1

公开(公告)日：2020-07-30

申请号：US15767141

申请日：2017-06-26

Applicant: CHINA UNIVERSITY OF MINING AND TECHNOLOGY

Inventor： Bai quan LIN ,  Yihan WANG ,  Fazhi YAN ,  Xiangliang ZHANG

IPC: E21B43/00 ,  E21B43/26

Abstract: A blockage removal and permeability enhancement method for coalbed methane wells by using electric pulses is applicable to high-efficiency exploitation of coalbed methane wells. The blockage removal and permeability enhancement method includes: constructing a positive electrode coalbed methane wellbore and a negative electrode coalbed methane wellbore from the ground to a coal bed; when the gas yield declines because cracks in the coal bed are closed gradually or blocked by granular impurities as coalbed methane extraction goes on after hydrofracturing, injecting a conductive ion solution into the positive electrode coalbed methane wellbore to fill the coal bed between the positive electrode coalbed methane wellbore and the negative electrode coalbed methane wellbore with the conductive ion solution; placing a positive electrode and a negative electrode downwards to predetermined permeability enhancement portions of the coal bed in the positive electrode coalbed methane wellbore and the negative electrode coalbed methane wellbore respectively; and breaking down, by using high-voltage electric pulses discharge, the coal bed filled with the conductive plasma solution between the positive electrode and the negative electrode, where shock waves generated from a large amount of energy act on the coal bed to cause the closed cracks in the coal bed to be opened again and extend and to remove the granules blocking the cracks, such that the number of the cracks in the coal bed is effectively increased and crack connectivity is improved.