二连盆地霍林河地区低煤阶煤层气成藏条件及主控因素

Conditions and major controlling factors of coalbed methane accumulation in coal reservoirs with low coal rank in the Huolinhe area,Erlian Basin

我国越来越重视对低煤阶煤层气的勘探,但已有的资料表明,目前对低煤阶煤层气藏的认识还不够深入。为此,以我国典型的低煤阶煤层气区——二连盆地霍林河地区为例,对该区煤层气地质特征和煤岩煤质及煤岩演化程度、煤储层渗透性、煤层含气性等煤储层特征进行了分析,从构造条件、封盖条件及水文地质条件3个方面研究了煤层气藏主控因素及保存条件。结论认为:霍林河地区煤层气成藏条件有利,具有煤层厚度大、煤层埋深较浅、煤储层渗透性好、含气量较高、封闭保存条件好等特点;保存条件是该区煤层气成藏的主控因素,且封闭条件好的浅部是煤层气富集的有利区。

Exploration of CBM in coal reservoirs with low coal rank has been drawing more and more attentions in China.However,current available data show that the CBM reservoirs with low coal rank are still poorly understood.By taking the Huolinhe area in the Erlian Basin,a typical Chinese CBM gas zone with low coal rank,as an example,we analyzed the CBM geological features,quality and thermal maturity of coals as well as permeability and gas potential of coal reservoirs.The major controlling factors and preservation conditions of CBM reservoirs are studied in respect of structural,sealing,hydrogeologic conditions.The coal reservoirs in the Huolinhe area are featured by large thickness,shallow burial depth,high permeability,high gas content,good seals,thus are favorable for CBM accumulation.Sealing is the major factor controlling CBM accumulation in the study area,and favorable CBM plays exist in shallow layers with good seals.