Abstract:

Coalbed methane resource is huge above 2 000 m in buried depth. An injection of CO₂ into coalbed can increase coalbed methane recovery, which can increase coalbed methane yield by 3.751×10¹² m³ above 2 000 m in buried depth. This paper, from multi-gas competitive absorption, coal volume expansion after CO₂ injection and its influence over penetrability and mechanics, and on-site tests, gives an introduction to its development progress worldwide. The on-site tests in several nations acquired similar results. This paper presents some factors needing consideration in study and on-site tests, such as the relation between multi-gas competitive absorption and coal molecular structure, absorption expansion volume and gas injection volume, relation between injection pressure and coal ranks, and safety issue by volume expansion after CO₂ injection into coalbed during mining.

Key words: CO_2ECBM, competitive absorption, absorption expansion, on-site test, penetrability

摘要：

中国埋深2 000 m以浅的煤层气资源潜力巨大。研究表明，向煤层中注入CO₂提高煤层气采收率技术具有巨大潜力，能够实现中国2 000 m以浅煤层气产量增产3.751×10¹²m³。本文从多元气体的竞争吸附、煤吸附CO₂之后的体积膨胀及其对渗透率和力学性质的影响以及世界各地的现场试验3个方面介绍这一技术在世界范围内的发展历程和研究进展。列举了几个国家利用这一技术的现场试验情况，试验结果较为相似。最后指出了在室内研究和现场测试中需要考虑的一些问题，诸如多元气体竞争吸附与煤分子结构的关系研究、吸附膨胀量和气体注入量、注入压力和煤阶之间的关系研究、注CO₂引起的吸附膨胀对后期煤矿采煤作业的影响和安全威胁。

关键词: CO₂ECBM, 竞争吸附, 吸附膨胀, 现场测试, 渗透率