公开(公告)号：US20220251956A1

公开(公告)日：2022-08-11

申请号：US17501129

申请日：2021-10-14

Applicant: TAIYUAN UNIVERSITY OF TECHNOLOGY

Inventor： Zhen LI ,  Xiaojun Yang ,  Peng Yang ,  Zhilong Fang ,  Jiapeng Zhao ,  Weichao Fan ,  Chunwang Zhang ,  Wenpu Li ,  Haina Jiang

IPC: E21F7/00 ,  E21B43/00

Abstract: A multi-level cross-district surface well pattern deployment method is provided. Firstly, a first horizontal well is drilled from a location on a land surface corresponding to a junction H1 of a district rise coal pillar of the first district C1 in a first level and an upper mine field boundary coal pillar. A multilateral well is drilled from a location on the land surface corresponding to a junction H3 of a level coal pillar between the first and second levels, and the district rise coal pillar of the first district C1 in the first level. Liquid nitrogen is injected for permeability improvement after a gas drainage quantity decreases to 20% of an initial quantity. Gas drainage is repeated multiple times until the drainage quantity of coal bed methane through a gas drainage pipe of the horizontal pipe is reached 3 m3/min.

公开(公告)号：US11649701B2

公开(公告)日：2023-05-16

申请号：US17501129

申请日：2021-10-14

Applicant: TAIYUAN UNIVERSITY OF TECHNOLOGY

Inventor： Zhen Li ,  Xiaojun Yang ,  Peng Yang ,  Zhilong Fang ,  Jiapeng Zhao ,  Weichao Fan ,  Chunwang Zhang ,  Wenpu Li ,  Haina Jiang

IPC: E21B43/00 ,  E21B43/30 ,  E21F7/00 ,  E21B43/26

CPC classification number: E21B43/006 ,  E21B43/2605 ,  E21B43/305 ,  E21F7/00

Abstract: A multi-level cross-district surface well pattern deployment method is provided. Firstly, a horizontal well is drilled from a location on a land surface corresponding to a junction H1 of a district rise coal pillar of the first district C1 in a first level and an upper mine field boundary coal pillar. A multilateral well is drilled from a location on the land surface corresponding to a junction H3 of a level coal pillar between the first and second levels, and the district rise coal pillar of the first district C1 in the first level. Liquid nitrogen is injected for permeability improvement after a gas drainage quantity decreases to 20% of an initial quantity. Gas drainage is repeated multiple times until the drainage quantity of coal bed methane through a gas drainage pipe of the horizontal pipe is reached 3 m3/min.