塔北隆起英买2井区碳酸盐岩储层特征及岩溶模式

中国海相碳酸盐岩储层具有鲜明的非均质性特征及复杂的形成机理。应用三维地震、岩心、成像测井、薄片等资料对英买2井区储层特征进行了研究，认为该区域储层并非典型的风化壳型岩溶储层，而属于断裂岩溶或断控岩溶储层，储集空间以方解石半充填或未充填的裂缝、小型溶蚀孔洞-裂缝为主，且分布受到断裂系统的强烈控制。结合构造活动背景以及包裹体盐度综合分析，认为该区断裂岩溶先后经历了地表水沿断裂向下溶蚀和深部热液沿断裂向上溶蚀2个阶段。前者以建设性作用为主，后者以破坏性作用为主。塔北地区油气勘探过程中，应突破以风化壳岩溶储层为主体的勘探思路，寻找多种类型的储层目标，其中断裂（控）岩溶储层可望成为该区域未来重要的勘探领域。

Carbonate reservoir features and karst mode in the Yingmai-2 well field of Tabei uplift

Marine carbonate reservoirs in China are of a distinctive heterogeneity and complex formation mechanism, which have been all along a focus concerned by oil and gas exploration of China. We examined reservoir characteristics of the Yingmai-2 well field by applying various data of 3D seismic attributes, cores, imaging loggings and thin sections. It was concluded that reservoirs in the Yingmai-2 well field are not typical weathering-crust karst but faulted or fault-controlled karst. The reservoir space includes mainly fractures unfilled or semi-filled with calcite, small corroded vugs and cracks, and its distribution is strongly controlled by faults. Based on comprehensive analyses of structural activity background and fluid inclusion salinity, we thought that faulted karst in the study area experienced successively two corroded processes, one is surface water corrosion downward along faults and the other is hydrothermal fluid corrosion upward along faults. The former is predominantly constructive to the formation of reservoirs, while the latter is mainly destructive. The study result showed that it is not enough to search only for weathering-crust karst reservoirs in oil and gas exploration of the Tabei area, thus, more attentions should be paid to other types of reservoirs, among which fault-controlled karst is very promising to be the next significant exploration target in this area.