注水压裂技术在焦作大水矿区煤层气开发中的应用

河南焦作矿区是我国著名的大水矿区，主采的二₁煤层含气量较高，一般在10~ 20 m³/t，是开发煤层气的理想区块。但煤岩本身渗透率普遍较低并且具有很强的压缩性，进而导致难以自然开采。为了探索矿区压裂抽采试验成功与失败的原因，通过对二₁煤层与底板的力学特征、构造特征、水文地质特征以及抽采试验的工艺数据的实例分析，阐明了水文地质作用对煤层气赋存及压裂抽采井产能的影响机理，即强烈的地下水径流作用，使原先游离于储层空隙中的煤层气逸散殆尽，孔隙水压也使得大量吸附于裂隙中的煤层气难以解吸，因而无法形成长期稳定的单井规模产量。

Application of water injection fracturing technology in coalbed methane development of Jiaozuo mining area with large water quantity

The mining area in Jiaozuo，Henan province is a famous large water filled mining area in China. The gas content of the Ⅱ₁ coal seam is relatively high，generally in the 10～20 m³/t，which makes it an ideal block for exploiting coal bed gas. But the coal rock′s permeability is generally low and it has a very strong compressibility，resulting in the difficulty of mining. To explore the reasons for the success and failure of the fracturing extraction experiment in diggings，through practically analyzing the mechanical characteristics，structural characteristics and hydrogeological characteristics of the Ⅱ₁ coal seam and the seam floor，as well as the process dates of fracturing extraction experiment，this article clarified the mechanism that how hydrogeological function effects the occurrence of coal bed gas and the capacity of the pumping well. The fierce river course of underground water makes almost all the coal bed gas escape from the interspaces of reservoir stratums where it stayed. And additional water pressure makes it difficult for much coal bed gas absorbed in fissures to escape，so it can not form a long-term stable single well scale output.