Method for integrated drilling, slotting and oscillating thermal injection for coal seam gas extraction

US10060238B2 · kind B2 · utility

Assignee

• China University of Mining and Technology · CN

Inventors

• Baiquan Lin · Shanghai, CN
• Chang Guo · Taipei, TW
• Quanle Zou · 安丰镇, CN
• Ting Liu · Xuzhou, CN
• Chuanjie Zhu · 安丰镇, CN
• Jia Kong · 安丰镇, CN
• Fazhi Yan · 安丰镇, CN
• Hao Yao · 安丰镇, CN
• Yidu Hong · 安丰镇, CN

Key dates

• Filing date: Dec 22, 2015
• Grant date: Aug 28, 2018
• Expiry date: Apr 28, 2036

Classification

• Technology area (CPC E): Fixed Constructions
• CPC primary: E21B41/0078
• WIPO field: Civil engineering
• WIPO sector: Other fields

Abstract

A method for combining integrated drilling and slotting with oscillating thermal injection to enhance coalbed gas extraction, applicable to managing gas extraction from microporous, low-permeability, high-adsorption coal seam areas. A number of slots are formed within a thermal injection/extraction borehole by means of integrated drilling and slotting technology; a steam generator, is then used to three high-pressure, cyclically temperature-changing steam into said borehole; the steam passing through a spinning, oscillating-pulse jet nozzle forms an oscillating superheated steam, heating the coal body. The present method overcomes the limitations of simple permeability-increasing techniques, the slotting by means of hydraulic. pressure significantly increasing the pressure relief range of a single borehole and forming a fracture network that provides channels for passage of the superheated steam, while oscillating variation in steam temperature and pressure also promote crack propagation and perforation of the coal body; the combined effect of the two enhances the efficiency of gas desorption and extraction.