江汉盐湖盆地同位素特征与油气藏形成环境

On Some Isotopic Features and Environment of Oil and Gas Accumulation in Jianghan Salt Lake Basin

江汉盐湖盆地为一封闭的高盐度湖相沉积盆地,其母源物质富含碳酸盐。潜江组沉积环境是一种还原环境。潜四段至潜三段的岩盐为深水浓缩成盐,而潜二段至潜一段的岩盐为常规浅水蒸发成盐。岩盐沉积不仅提供了良好的油气藏盖层,其共生岩系还可形成优良的烃源岩层系。另一方面还可形成独特的盐湖沉积体系砂体-盐湖密度流砂体,十分有利于岩性油藏的形成与油气藏勘探。

This paper synthetically analyzes some isotopic features of oxygen, carbon, sulphur, boron and chlorine from Qianjiang Formation of Qianjiang Depression in Jianghan Basin, and thinks that Jianghan Salt Lake Basin is a closed lacustrine sedimentary basin with high salinity and with abundance of carbonate in source material. The sedimentary environment of Qianjiang Formation is a reducing environment. All rock salt from Qian-4 Member to Qian-3 Member is concentrated into salt in deep water, while all rock salt from Qian- 2 Member to Qian- 1 Member is conventionally evaporated into salt in shallow water. Rock salt sedimentation provides good caprocks for oil and gas reservoirs, what＇s more, its commensal rock formations can come into being good hydrocarbon source rock series of strata. On the orther hand, rock salt sedimentation can also generate some unique salt lake sedimentary systematic sand bodies salt lake density flow sand bodies, which are very beneficial for generating lithological reservoirs and exploration of oil and gas reservoirs.