琼东南盆地陵水13-2气藏凝析油生物标志物检测及油气源对比

The Detection of Biomarkers and Their Application in Hydrocarbon Source Correlation of Condensate Oil from Lingshui 13-2 Gas Reservoir in Qiongdongnan Basin

为分析琼东南盆地深水气藏的气源及其成藏地质条件,针对其深水气藏(邻近深水区陵水13-2和深水区陵水17-2)凝析油轻烃组分多、常规方法难以检测到甾萜烷生物标记物信息而无法开展有效的油气源对比追踪等问题,采用ZSM-5型分子筛对饱和烃络合等手段,成功获取了一系列甾、萜烷系列化合物信息,进而为深水气藏的气源追踪判识提供了重要依据。根据深水气藏伴生凝析油中的生物标志物特征,即代表陆源高等植物的奥利烷含量异常丰富以及树脂生源的双杜松烷类脂化合物含量中等和规则甾烷组成中表征高等植物的C29胆甾烷远大于低等水生生物C27胆甾烷等重要生源信息,综合判识与确定了研究区深水气藏的油气源主要来自渐新统崖城组三角洲前缘煤系半封闭浅海烃源岩。

In order to analyze the gas source and geological conditions of accumulation of deep gas reservoir in Qiongdongnan Basin,in view of the problems of multiple light hydrocarbon components,the conventional method being difficult to detect the bio-marker information of the oil and gas and difficult for effective carrying out oil source correlation and tracking in Lingshui 13-2 and Lingshui 17-2 Condensate Gas Reservoirs,a series of steroid and terpane compounds are detected after complexing saturated hydrocarbon by ZSM-5 molecular sieve and GC-MS analysis,the information of a series of steroid and terpene compounds is successfully obtained,and then an important basis is provided for gas source identification and tracking.The results show that in Lingshui 13-2 Condensate Gas Reservoir,biomarker oleanane content is unusually rich,which indicates a terrestrial higher plant source.Double cadinane content is in the medium level,which originates from angiosperms resin.Stigmastane C29ααα-20 R(derived from higher plants)is more than cholestane C27ααα-20 R(originates from lower aquatic organisms cholestane).It is comprehensively identified and determined that the oil and gas sources of deep water gas reservoirs in the study area mainly come from the front coal measures and semi-closed shallow sea source rocks in the delta of the Oligocene Yancheng Formation.