中文摘要：

沁水盆地南部地区上古生界海陆过渡相煤系碎屑岩中气测异常现象极为普遍,具有较好含气显示的致密砂岩及泥岩段与裂缝发育程度密切相关,该类含气储层应定义为裂缝性致密碎屑岩储层。受特殊构造演化及复杂成岩作用的综合影响,该区煤系碎屑岩中裂缝发育特征具有一定特殊性和复杂性,且研究程度较浅。基于该现状,综合利用钻井、岩心、测井、压裂、薄片及力学测试等资料,对该地区山西组碎屑岩地层裂缝发育特征进行了综合研究。结果表明,所研究碎屑岩地层普遍经历了强压实及强胶结作用,孔隙度普遍低于5%。裂缝的存在能显著提高不同类型孔隙间的连通性,显著改善储层物性,提高渗流能力。砂岩中以发育构造缝为主,包括张性缝、剪切缝及少量挤压缝,非构造裂缝主要包括溶蚀缝;泥岩中构造缝和非构造缝均较为发育,构造缝包括剪切缝及少量张性缝及滑脱缝,非构造缝包括层理缝、溶蚀缝及成岩收缩缝。砂岩中裂缝要比泥岩中裂缝更为发育。目的层碎屑岩中以中—低角度缝为主,裂缝充填类型以未充填及半充填裂缝为主,均为有效裂缝。较好的裂缝有效性与该地区特殊的构造演化特征密切相关,喜马拉雅运动期强烈的隆升剥蚀对煤系进行了强烈的改造,主要体现在应力大幅度卸载、地层温度的强烈降低及张性应变量的产生3个方面。该改造作用一方面可使煤系原本紧闭的裂缝重新张开成为有效缝;另一方面可产生一些新的张性裂缝,这是研究区煤系碎屑岩中张性裂缝较为发育的重要原因。这些张性缝的形成时期较晚,多未充填,有效性好。基于以上认识,加强裂缝发育层段的精细解释及裂缝发育＂甜点区＂的准确预测对实现裂缝性致密碎屑岩储层天然气突破具有现实意义。

英文摘要：

Gas logging abnormal phenomenon is extremely common of the sea-land transition phase clastic rock in the Upper Palaeozoic in the Southern Qinshui Basin.The good gas shows in tight sandstone and mudstone intervals are closely related to the degree of fracture development,this kind of gas reservoir should be defined as fracture clastic rock reservoir.Being influenced by special tectonic evolution and complicated diagenesis,the fracture development characteristics in the clastic rock strata have certain particularity and complexity,and the research degree is shallow.Based on the present research situation,comprehensive utilization of drilling,cores,logging,fracturing tests,slice and mechanics test data of clastic rock strata of Shanxi Fm.,comprehensive research of fracture development characteristic in this region has been carried out.Results show that the clastic rock formation has generally experienced strong compaction and cementation,its porosity is generally lower than 5%.The existence of fractures can significantly improve the connectivity between different types of pores,which can significantly improve the reservoir property,especially improve the ability of seepage properties.Sandstones mainly develop structural fractures,including tensile fractures,shear fractures and a small amount of extrusion fractures,non-structural fractures mainly include dissolution fractures;structural fractures,non-structural fractures are developed both in mudstones,with structural fractures including shear fractures and a small amount of extensional fractures and slippage fractures,non-structural fractures includes bedding fractures,dissolution fractures and diagenetic shrinkage fractures.Fractures are much more developed in sandstones than in mudstones.Fractures of clastic rock in the purpose layer are given priority to medium-low angle fractures and the fractures filling type is given priority to unfilled and half-filled fractures,these fractures are effective.The good fracture effectiveness is closely related to the special te