School of Earth Resources, China University of Geosciences (Wuhan) Key Lab of National Energy Coal and
Coalbed Methane Joint Mining Technology, Shanxi Jincheng Anthracite Mining Group Co., Ltd. School of
Engineering, China University of Geosciences (Wuhan)

为了进一步认识煤层气排采过程中储层压降传递规律及其对煤层气排采的影响,在煤储层裂缝系统发育与分布特征观察研究的基础上,分别建立了煤裂缝系统及煤基质内压降传递地质模型,并分析总结了储层压降传递影响因素及其相互关系。结果表明:煤储层压降传递及动态变化主要受储层渗透率、含水性、含气饱和度、煤解吸/吸附特性以及井底流压影响,其中储层大裂缝系统内的压降传递主要与渗透率、含水性以及井底流压相关;而煤基质内的压降传递则主要与含气饱和度及煤解吸/吸附特征相关。鉴于储层压降传递及其影响因素在煤层气排采中的作用,提出煤层气排采前应首先掌握影响储层压降的地质参数特征;排采过程中井底流压的控制应充分考虑影响储层压降的各因素之间的联系。

In order to further understand a pressure drop transfer law of the coal reservoir during the coalbed methane drainage process and pressure drop transfer law affected to coalbed methane drainage, based on an observation study on the development and distribution features of the cracking system in the coal reservoir, a C oal cracking system and coal matrix pressure drop transfer geological model were established individually and the pressure drop transfer influence factors and the relati onship of the coal reservoir were analyzed and summarized. The result showed that pressure drop transfer and dynamic variation of the coal reservoir were affected ma inly by the reservoir permeability, water-bearing ability, gas saturation, coal desorption/adsorption features and the well bottom flow pressure and among them, the pres sure drop transfer within the large cracking system of the reservoir would be mainly related to the permeability, water-bearing ability and the well bottom flow pressure. Within the coal matrix, the pressure transfer would be mainly related to the gas saturation and the coal desorption/adsorption features. Due to the reservoir pressure dr op transfer and the influence factors plaid the role in the coalbed methane drainage, the geological parameter features affected to the pressure drop of the reservoir sh ould be understood before the operation of the coalbed methane drainage. The well bottom flow pressure control in the gas drainage process should fully consider the r elationship between the pressure drop influence factors of the reservoir.