Thermochemical sulfate reduction and fluid evolution of the Lower Triassic Feixianguan Formation sour gas reservoirs,northeast Sichuan Basin,China
作者单位：Key Laboratory of Petroleum Resources ResearchInstitute of Geology and GeophysicsChinese Academy of Sciences University of Chinese Academy of Sciences Department of Earth and Ocean SciencesSchool of Environmental SciencesLiverpool University
会议名称：《中国科学院地质与地球物理研究所2014年度（第14届）学术年会》
会议日期：2015年
学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程]
基 金：financially supported by the United Foundation of the National Natural Science Foundation of China and China’s Petroleum Chemical Industry(Grant 40839906) China National Funds for Distinguished Young Scientists(41125009) an award from the Chinese Scholarship Council for a joint Ph.D.project in the United Kingdom with R.H.Worden supported by the 12th Five-Year National Key Petroleum Project(2011ZX05008-003)
摘 要：The dolomite-hosted,Lower Triassic Feixianguan Formation from the northeast Sichuan Basin,China,is an economically important reservoir that contains sour natural *** reservoirs were initially filled with oil,later replaced by gas during burial to 7000 m(22,965 ft) followed by uplift to about 4000 m(13,123 ft).We have studied the souring process(thermochemical sulfate reduction[TSR]) and diagenetic evolution of the Feixianguan Formation using detailed petrology,fluid-inclusion studies,and stable-isotope data from carbonate *** diagenesis included(in time order) the eodiagenetic main stage of dolomitization by a reflux mechanism;fracture-related calcite cementation;barite,quartz,celestite,and fluorite mineralization;and a dolomite recrystallization *** sulfate reduction resulted in anhydrite replacement by calcite,petroleum destruction,formation of sulfur-rich pyrobitumen and elemental sulfur,and generation of large volumes of HS and *** during TSR can be subdivided into oil-stage TSR and gas-stage TSR,with oil-stage TSR defined by the presence of primary oil and bitumen inclusions in the TSR *** on aqueous inclusion homogenization temperatures,oilstage TSR commenced at a temperature of 116℃,with a mode between 130℃ and 140℃.Gas-stage TSR started at a temperature of 135℃ and continued to maximum burial temperatures of about 220℃.Trace amounts of pyrite,barite,quartz,and celestite grew during ***-TSR diagenesis was dominated by fracture-related calcite precipitation as well as celestite and anhydrite *** water salinity increased from depositional values(3.5 wt.%) up to 24 wt.%during pre-TSR dolomite recrystallization probably because of an influx of evaporite-associated water from the overlying Jialingjiang Formation,although pre-TSR barite,quartz,celestite,and fluorite mineralization was associated with a transient decrease in water *** TSR,formation water salinity decreased