Study Of The Chang10Reservoir Characteristics And It’s Influencing Factors In Ansai Oilfield Of The Ordos Basin

The Triassic Yanchang Formation of the Ordos basin is not only the first researched and fully developed typical section of continental Triassic strata in China, but also the first hydrocarbon reservoir discoveries in the basin, and it was always the main oil exploration and development strata for years. Since the well Gao52which drilled over the Chang10strata of the Ansai area was completed in2007and obtained64.7t natural commercial oil flow per day, it’s production test manifested that Chang10strata had huge exploration potential. The purpose of this thesis was to conduct some research on the characters of Chang10Reservoir strata as well as predicting the potential areas for reservoirs development.Based on the study results done by the previous researchers, combining with the petrographic and logging phase analysis, the conclusions can be made that sedimentary facies of Chang10strata in the Ansai area was delta plain subfacies, including distributary channel, natural levees, crevasse splay, floodplain and so on sedimentary microfacies, the favorable reservoir sandbody was distributary channel. According to a large number of core observation, with methods of test analysis of thin section identification, casting analysis, mercury injection Scanning electron microscope(SEM) and size analysis, the data show that the rock types of Chang10reservoir is mainly arkose and debris-arkosic sandstone, The pore type is mainly the intergranular pore; The pore structure belongs to mesoporous and medium-fine throat type; The main diagenesis are mechanical compaction, cementation, replacement and dissolution, etc. Comprehensive analysis indicate that the diagnesis stage in Chang10reservoir sandstone is during the A stage of late diagenetic process.Chang10reservoir is mainly affected by the influence of sedimentary facies, terrigenous clastic components and diagenesis. The cementation, compaction and dissolution of chlorite, carbonate, demethicone, authigenic clay mineral are also the main factors that influence reservoir qualities.After a comprehensive study, this theses predict5potential exploration areas in the main produce layer of Chang1012reservoir, they are Wang525, Xing212, Hou104, Dan52and Gao50well areas respectively.