鄂东北缘低阶煤渗透性特征及主控因素

Permeability characteristics and key controlling factors of low rank coal in Northeastern Erdos Basin

为了分析低阶煤储层渗透率对煤层气勘探选区和产能建设的影响,在分析煤层气储层渗透率特征的基础上,通过煤层地应力、埋藏深度、显微组分、煤级及割理间距、煤体结构与渗透率之间相关性分析,探讨鄂尔多斯东北缘低阶煤渗透率主控因素。结果表明,该区低阶煤储层渗透率高于我国中高阶煤层气田煤储层渗透率,且主要受到煤级及割理间距和地应力的共同作用,煤级及割理间距通过煤演化过程改变煤岩力学性质控制渗透率,地应力通过影响割理的开启程度和方向控制渗透率,而埋藏深度与渗透率相关性不强。

In order to discuss the impact of permeability of low-rank coal reservoirs on coalbed methane exploration area and productivity construction,the relationships between permeability and crustal stress,burial depth,micropetrological unit,coal rank,cleat spacing and coal structure were applied to analyze the control of permeability on the basis of coalbed methane reservoirs permeability characteristics in the northeastern margin of Ordos Basin.The results showed that the permeability in the area,higher than medium-high rank coal reservoirs permeability,was mainly controlled by coal rank,cleat spacing and crustal stress. Coal rank and cleat spacing affected permeability by changing coal mechanical property during coalification.Crustal stress influenced permeability by controlling the spacing and direction of cleat.Other parameters,such as burial depth,micropetrological unit,had insignificant influence on permeability in the area.