摘要
通过对西昌盆地北部中所镇至冕山镇之间的南箐乡背斜剖面野外地质调查研究,认为上三叠统白果湾组砂岩地层中存在古油藏痕迹。对白果湾组储层抽提物有机地化指标分析,表明储层中的烃类是烃源岩处于成熟期的产物,烃源岩沉积环境为高盐度的缺氧还原环境。通过对储层抽提物与各烃源层进行烃源对比研究,表明西昌盆地西北部南箐构造区白果湾组古油藏的烃源为混合来源,除有盆地北部白果湾组陆相烃源外,还混有下伏海相地层烃源。南箐地区古油藏接受白果湾组烃源充注的时间应当在早白垩世之后,古油藏的烃源具有混合充注的地质背景。白果湾底部与古生界地层接触的不整合面为多套烃源层的油气提供运移通道。
By an outcrop investigation to Nanqing anticlinal profile, located between Zhongsuo and Mianshan towns in northern Xichang Basin, it is considered that palaeo reservoir trace exists in Upper Triassic Baiguowan sandstone. In addition, by an analysis of organic geochemical index of the reservoir extraction from Baiguowan sandstone, it is indicated that the reservoir is a product of matured source rocks,which deposited in an anoxic reducing environment with high salinity. A source correlation was made between reservoir extraction and every source bed, reflecting that the source of Baiguowan sandstone palaeo reservoir in northwestern basin belongs to a mixed source from either Baiguowan continental source or underlying marine source in northern basin. The time of Baiguowan source entering into palaeo reservoir should be after early Cretaceous. An unconformity, which occurs between the bottom of Baiguowan sandstone and Palaeozoic, is the main migration channel to connect many Palaeozoic source beds.
出处
《天然气勘探与开发》
2008年第3期6-9,共4页
Natural Gas Exploration and Development
关键词
西昌盆地
上三叠统
白果湾组
古油藏痕迹
Xichang Basin
Upper Triassic
Baiguwan formation
Palaeo reservoir trace
