莱州湾凹陷火山岩-湖相碳酸盐岩混积岩储层特征和成因

渤海海域首次在莱州湾凹陷沙河街组发现火山岩-湖相碳酸盐岩混合沉积，其储层成因机理尚不明确.通过铸体薄片、氩离子抛光扫描电镜、背散射、岩心CT扫描等资料，落实了混积岩具有孔隙和裂缝双介质型储集空间.湖相碳酸盐岩沉积时期伴随火山活动间歇性喷发，发育了4种混合沉积方式.火山喷发提供了大量凝灰质组分，为后期流体选择性溶蚀提供良好的物质基础.地层中微松藻化石的发现揭示了混积岩经历过长期暴露地表过程，经受了大气水风化淋滤作用，是优质储层形成的重要因素.区域构造运动在储层中形成大量垂直裂缝和低角度层间水平滑脱缝，在火山热液叠加溶蚀作用下发育热液溶蚀孔洞和沿裂缝溶蚀扩大孔，大大改善了储层物性，形成裂缝-孔隙型优质储层. 

Reservoir Characteristics and Formation Mechanisms of Lacustrine Carbonate and Volcanics Mixing Sediments,Laizhouwan Sag

It is the first time to find the mixed deposition of lacustrine carbonate and volcanics in Shahejie Formation, Laizhouwan sag, Bohai Sea area. The genetic mechanism of this kind of reservoir is not clear. By casting thin section, Ar-ion milling scanning electron microscope and core 3D CT scanning data, it is confirmed that the interstitial rock is a double medium storage space of pores and fractures. The lacustrine carbonate sediments were accompanied by intermittent eruptions of volcanic activities during the sedimentary period, and four kinds of mixed sedimentary modes developed. Volcanic eruptions provide a large number of tuff components which provide conditions for fluid selective dissolution. In addition, the fossils of microcodium were found in the strata, indicating that the interstitial rocks had undergone long-term exposure, and the interstitial rocks had undergone atmospheric water weathering and leaching. A large number of vertical fractures and horizontal slippage joints between low angle layers were formed in the reservoir due to tectonic action. The superposition of fractures and dissolution pores forms a fracture-pore reservoir.