鄂尔多斯盆地西北部盒8段流体包裹体特征与油气成藏研究

Fluid inclusions and hydrocarbon accumulation in the eighth member of the Lower Shihezi Formation in northwestern Ordos Basin

摘要: 根据油气包裹体特征及含烃盐水包裹体均一温度,结合埋藏史分析,对盒8段油气藏进行了成藏期次综合研究。盒8段油气藏历经四期油气充注过程:第一期发生在219~209M a (晚三叠世中期);第二期发生在191~183Ma (早侏罗世中期);第三期发生在145~130Ma (早白垩世早中期);第四期发生在122~115Ma (早白垩世晚期)。

Abstract: The relationship between the fluid inclusions and hydrocarbon accumulation in the eighth member of the Lower Shihezi Formation in northwestern Ordos Basin is based on diagenetic sequences,homogenization temperatures,freezing point temperatures,salinity and density of the hydrocarbon inclusions and hydrocarbon-bearing salt water inclusions,in integration with structural features,burial history,vitrinite reflectance,apatite fission-track dating.Four phases of hydrocarbon accumulation are identified for the study area,including:(1) 219-209 Ma(middle Late Triassic);(2) 191-183 Ma(middle Early Jurassic);(3) 145-130 Ma(early-middle Early Cretaceous),and(4) 122-115 Ma(late Early Cretaceous).