三交区块水文地质条件对煤层气富集高产控制作用
Hydrogeological condition control effect on coalbed methane enrichment and high production in Sanjiao Block
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摘要: 为了研究水文地质条件与煤层含气性及煤层气产能之间的关系,基于三交区块煤层气井产能在水平上和垂向上存在显著差异,通过对该区水文地质特征进行深入剖析,探讨了其对煤层含气性及气井产能的影响,揭示了水文地质条件对煤层气富集高产的控制作用。研究结果表明:区域上,研究区中南部碛口一带地下水活动弱、矿化度高,为煤层气富集高产的优势区域,具有高含气量、高产气量、低产水量、短排水期的特点;垂向上,山西组地层水较太原组矿化度高,水动力弱,更有利于煤层气富集高产,导致3+4+5号煤层较8+9号煤层含气饱和度高、产气量高、产水量低、排水期短,此外,8+9号煤层顶部灰岩含水层与断层相互作用,不利于煤层气的富集和高产。Abstract: Due to the significant regional and vertical differences of production capacity of coalbed methane wells in Sanjao Block, in order to study relationships b etween hydrogeological conditions and coalbed methane content and production capacity, then the hydrogeological controls on coalbed methane enrichment and high p roduction were revealed.The research results showed:in area, the groundwater activity was very weak and its mineralization degree was high in the region near Qikou A rea, in the south-central of the study area, which was the superior district for coalbed methane enrichment and development with high gas content and production, low water production and short drainage period.In vertical, compared to Taiyuan Formation, the groundwater of Shanxi Formation had weaker activity and higher mineralizat ion degree, which was more favorable for coalbed methane enrichment and development, resulting that No.3+4+5 coal seam had higher gas saturation and production, I ower water production and shorter drainage period than No.8 + 9 coal seam.In addition, the interaction of limestone aquifer above No.8+9 coal seam and faults lead to negative effect on coalbed methane enrichment and development.