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黄桥地区CO2气田是我国陆上规模最大的CO2气田之一,主要是由古近纪以后岩浆火山活动地幔物质上涌形成的。该气田平面上临近深大断裂的交会部位,纵向上从下古生界到新近系盐城组都有分布。CO2是在相对较高温度下快速成藏的,且成藏时间晚于油气,二叠系—三叠系油气藏则以自生自储为主要特征。富含CO2的层位与主要的油气显示层位并不一致,CO2在向上运移的过程中很难将先进入储层的油气驱替出来,特别是在二叠系龙潭组致密的砂岩储层中。油气藏保存条件良好,但高温CO2带来的热量使原油大多热分解转化为轻质油,其品质好黏度低,有利于在物性相对较好的构造高点富集成藏。
The Huangqiao area CO2 gas field is one of the largest land-based CO2 gas fields in China, mainly formed by upwelling mantle volcano activity since the Paleogene. The gas field is near the intersection of the deep and deep faults in the plane, and is distributed longitudinally from the Lower Paleozoic to the Neogene Yancheng Formation. CO2 is rapidly accumulated at relatively high temperature and has a later accumulation time than oil and gas. Permian-Triassic reservoirs are characterized by self-genesis and self-storage. The CO2-rich horizon is not consistent with the main hydrocarbon-bearing horizon. It is very difficult for CO2 to displace the oil first advanced into the reservoir during its upward migration, especially in the tight sandstone reservoirs of the Longtan Formation in the Permian in. Oil and gas reservoirs are well preserved, but the heat caused by high temperature CO2 makes most of the crude oil decompose into light oil by thermal decomposition, and its good quality and low viscosity are conducive to the enrichment of reservoirs at structurally high points with relatively good physical properties.