川东地区黄草峡构造飞仙关组沉积相与储层特征

Sedimentary facies and reservoir characteristics of Feixianguan Formation in Huangcaoxia structure of East Sichuan

刘 为 徐国盛 黄小琼 王德斌 龚德瑜 朱建敏 段 亮

成都理工大学油气藏地质及开发工程国家重点实验室，四川 成都 610059 中国石油西南油气田分公司勘探开发研究院，四川 成都 610051

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu 610059, China Research Institute of Exploration and Development, Southwest Oil-Gas Field Company, PetroChina, Chengdu 610051, China

通过岩心、薄片、测井资料的综合分析，认为川东地区黄草峡构造飞仙关组总体为碳酸盐台地相沉积，可进一步划为台地边缘滩、台内点滩、开阔台地和潮坪中４个亚相。储集空间主要发育鲕内溶孔、晶间孔、晶间溶孔和构造缝、压溶缝；储集类型属裂缝-孔隙型。该区成岩作用与川东北广大地区存在较大的差异。通过沉积、成岩以及构造因素对储层的控制作用分析，建设性的成岩作用主要有同生期溶蚀作用、埋藏溶蚀作用及后期的构造破裂作用，但由于大气水溶蚀作用较弱，且缺乏关键性的与海水蒸发浓缩有关的白云石化作用，同时由于胶结作用、压实作用等破坏性成岩作用的影响，致使该区的优质海相碳酸盐岩储层欠发育且储层非均质性强，因此天然气勘探具有一定的风险。

Based on the analysis of core, thin section and well logging data, Feixianguan Formation in Huangcaoxia structure of East Sichuan is identified as carbonate platform sedimentary facies, which can be further classified into four subfacies that include the platform edge facies, point bar in platform, open-platform and tidal flat. The main reservoir spaces are intra-oolitic pore, intercrystalline pore, intercrystalline dissolved pore, tectonic fractures and pressolutional fractures. Therefore, the reservoir type is a fractured-porous one. Compared with the northeast part of Sichuan, the diagenesis of the study area is quite different. By the analysis of the controlling effect of sedimentary, diagenesis and tectonic factor to reservoir, constructive diagenesis mainly consist of the contemporary denudation, burial denudation and late tectonic disruption. However, some influence factors, such as weak meteoric water denudation, lacking of the critical dolomitization related to the evaporation and concentration effect of sea water and ruinous diagenesis of cementation and compaction, result in a poor development of high-quality marine carbonate reservoir and the strong reservoir heterogeneity. Therefore, there are some risks in gas exploration.