摘要
琼东南盆地深水区中央峡谷发育巨厚的第三系沉积,尤其是SS22-1、SS17-2气田的重要发现使之成为近年来油气勘探关注的热点地区。综合利用钻获天然气及烃源岩地化资料,并结合深水区地质条件,分析了中央峡谷天然气的组成特征与成因类型、来源及运聚机理。结果表明,中央峡谷上中新统黄流组的天然气以烃类气为主且干燥系数高,甲烷、乙烷碳同位素较重,属高成熟煤型气;天然气轻烃参数、甲烷氢同位素组成及烷烃气碳同位素指纹均与YC13-1气田天然气相似,伴生的凝析油检测出在崖城组烃源岩中普遍发现的奥利烷和树脂化合物等特征标志物,指示这些天然气可能主要来自陵水凹陷南斜坡前三角洲背景下的渐新统崖城组煤系及浅海泥岩富含的陆源有机质;进而建立了底辟(裂隙)沟源、浮力及深部高压驱动、晚期成藏的天然气运聚模式,由此预示在深水区除了中央峡谷之外,中央坳陷的北部断坡带、紧靠崖城组烃源灶的南部低凸起也是天然气聚集的有利场所。
The deep water area in Qiongdongnan basin has been one of the hydrocarbon exploration focuses in recent years because of its huge volume of Tertiary sediments,especially the major discoveries of SS22 and SS17 2 gas fields in its central canyon.By comprehensively applying the geochemical data from the discovered gas and source rocks and combining with the geology in the deep water area,the composition,origin,source and migration-accumulation pattern were analyzed for the gas in the central canyon.The results revealed that：（1） The natural gas in Upper Miocene Huangliu Formation is composed predominantly by hydrocarbon gas,high in drying coefficient and relatively heavier in carbon isotope of methane and ethane,and belongs to coal type gases with high maturity; （2） The light hydrocarbon parameters of gas,hydrogen isotope composition of methane and carbon isotopic fingerprints of hydrocarbon gas are similar to those of the gas in YC13 1 field,and the distinctive biomarkers generally found in the source rocks of Yacheng Formation,such as oleanane and resin,have been detected in the associated condensate,indicating that the gas may be primarily generated from the terrigenous organic matter in Oligocene Yacheng Formation coal-bearing sequence and neritic mudstones in a prodelta setting on the south slope of Lingshui sag; （3） From the hydrocarbon migration-accumulation pattern with diapir （fracture） pathway,buoyancy and deep high-pressure drives and late accumulation,it is predicted that besides the central canyon,the north faulted-slope zone in the central depression and the south low-uplift adjacent to the hydrocarbon kitchen in Yacheng Formation will also be favorable places for gas accumulation in the deep water area.
出处
《中国海上油气》
CAS
CSCD
北大核心
2014年第5期8-14,共7页
China Offshore Oil and Gas
基金
"十二五"国家科技重大专项"南海北部深水区潜在富生烃凹陷评价(编号:2011ZX05025-002)"部分研究成果
关键词
天然气
组成特征
成因类型
来源
运聚模式
中央峡谷
深水区
琼东南盆地
natural gas
composition
origin
source
migration-accumulation pattern
the central canyon
the deep water area
Qiongdongnan basin
