沁南潘河煤层气田区域地质特征与煤储层特征及其对产能的影响

Regional geological and reservoir characteristics of the Panhe CBM Gas Field in the southern Qinshui Basin and their influences on CBM gas production capacity

沁水盆地南部（以下简称沁南）潘河煤层气田是中国最早具有良好经济效益的规模化商业开发的气田,分析其区域地质与煤储层特征,评价其煤层气可采性和生产潜力,可为选择气田井网形式、钻完井技术、增产改造技术,确定适宜的排采制度提供基础和依据。为此,充分利用该区200多口煤层气生产井资料、以往煤田地质勘探资料和煤层气参数井资料,精细描述了煤层气田区域地质和煤储层特征,分析了影响煤层气产能的地质、储层因素。结果表明：该区地质构造简单,次级褶皱构造发育;煤层发育稳定,厚度大（3#煤层厚度为6.5 m左右）;煤变质程度高,属于无烟煤;含气性良好,含气量较高,但平面上变化较大,气体质量好,甲烷含量超过98%;含气饱和度高,介于95%~100%;渗透率相对较好,储层压力较高。总体上,地质和储层特征参数显示该区具有煤层气富集和高产的有利条件。根据PH1-009、TL-006、TL-007等煤层气参数井测试数据,以及潘庄一号井田的煤田勘探资料,建立了气田地质模型,以期指导今后的井网设计、工程技术选择,实现气田的高效开发。

The Panhe field in the southern Qinshui Basin is the first large-scale commercial CBM gas field with good economic benefits.Analysis of its regional geological and reservoir features as well as the evaluation of its recoverability and production potential can provide basic information for the selection of well pattern,drilling & completion and stimulation technologies as well as the determination of water drainage and gas production policies.Production data of over 200 CBM wells in the study area,previous geological exploration data of the coal fields,and data from CBM parameter wells are fully utilized to describe in detail the regional geological and reservoir features of this CBM field,and analyze the geological and reservoir factors influencing the CBM production capacity.The following conclusions are obtained.1) The geological conditions and structures are relatively simple in the study area with well-developed secondary folding.2) The coal seams are stable in distribution and large in thickness and the coal bed 3# is 6.5 m in thickness.3) The coal is anthracite with high metamorphic grade and its gas content is relatively high,but show large lateral variation.4) Gas quality is good with the methane content over 98% and gas saturation is high in the range of 95-100%.5) Both reservoir permeability and pressure are relatively high.As a whole,the geological and reservoir parameters reveal that this study area has favorable conditions for CBM enrichment and recovery.A geologic model is built based on the test data of parameter wells including PH1-09,TL-006 and TL-007 and the exploration data of the Panzhuang-1 coal field,providing valuable reference for the well pattern design,the selection of engineering technologies,and highly efficient development of similar CBM gas fields.