鄂西渝东地区石柱复向斜海相层系烃源研究

为研究石柱复向斜海相层系烃源条件，对该区钻井及露头样品进行了系统的有机地化分析。石柱复向斜海相层系发育多套烃源岩，各层位烃源岩TOC值差异大，其中下志留统龙马溪组下部，茅口组四段、上二叠统龙潭组TOC含量最高；各层位烃源岩有机质类型从Ⅰ型至Ⅲ型阶皆有，现今主要处于高成熟—过成熟晚期。石柱复向斜海相层系烃源条件优越，其中龙潭组、茅口组、韩家店组、龙马溪组为该区几套主力烃源层，而长兴组、栖霞组、凉山组、小河坝组、牛蹄塘组为次要烃源岩。龙潭组、龙马溪组高有机质丰度泥页岩除可为常规气藏提供充足烃源，同时自身也是页岩气的有利勘探层位。

Study on Hydrocarbon Source in Marine Sequences in Shizhu Synclinorium, Western Hubei-Eastern Chongqing Area

Geochemical analyses of well and outcrop samples show that many suites of source rocks were developed in the marine sequences in Shizhu synclinorium,western Hubei-eastern Chongqing area.Significant differences exist in TOC values of source rocks in different formations.Source rocks from the lower part of Longmaxi Formation,the fourth member of Maokou Formation and the upper Permian Longtan Formation have highest TOC values.Source rocks are composed of organic matter varying from type Ⅰ to type Ⅲ kerogen and are during the thermal stages from highly mature to overmature.Source rocks in the Shizhu synclinorium are dominated by those from the Longtan,Maokou,Hanjiadian and Longmaxi Formations.Source rocks from the Changxing,Qixia,Liangshan,Xiaoheba and Niutitang Formations are of subordinate important.Shale rocks with high TOC form Longtan and Longmaxi Formations in Shizhu synclinorium provide adequate hydrocaben gas for conventional gas reservoir,and they are also favorable zones for the shale gas exploration.