渤海湾盆地渤中凹陷太古宇变质岩潜山储集层垂向结构单元划分与识别

Division and identification of vertical reservoir units in Archaeozoic metamorphic buried hill of Bozhong Sag,Bohai Bay Basin,East China

综合利用岩心、壁心、铸体薄片、储集层物性、常规和成像测井等资料,建立渤海湾盆地渤中凹陷暴露型和覆盖型两类太古宇变质岩潜山储集层垂向结构单元划分方案,明确不同储集层结构单元的地质特征和储集空间构成,并确立其常规测井和成像测井识别标志。太古宇变质岩潜山垂向上可分为风化壳和潜山内幕两个一级储集层结构单元。风化壳可进一步划分黏土带、风化砂砾岩带、淋蚀带和崩解带4个二级储集层结构单元;潜山内幕中可识别内幕裂缝带和致密带2个二级储集层结构单元,其中内幕裂缝带可进一步细分为碎裂段和裂缝密集段。暴露型潜山有利储集层主要发育在风化砂砾岩带、淋蚀带、崩解带叠加碎裂段和内幕裂缝带碎裂段4个部位,储集层的形成受风化和构造改造双重控制;覆盖型潜山有利储集层主要发育在风化壳叠加碎裂段和内幕裂缝带碎裂段中,有利储集层发育主要受构造控制。

Based on the data associated with cores,sidewall cores,casting thin sections,reservoir physical properties,conventional logging and imaging logging,the classification schemes of vertical reservoir units are proposed for the two types of Archaeozoic buried hills(exposed and covered ones)in the Bozhong Sag,Bohai Bay Basin.The geological characteristics and storage spaces of these reservoir units are described,and their identification markers in conventional and imaging log curves are established.The Archaeozoic metamorphic buried hills can be vertically classified into two primary reservoir units:weathering crust and inner buried hill.The weathering crust contains four secondary units,i.e.,the clay zone,weathered glutenite zone,leached zone,disaggregation zone;and the interiors contain two secondary units,i.e.,interior fracture zone and tight zone.In particular,the inner fracture zone was further divided into cataclasite belts and dense-fracture belts.It is proposed that the favorable reservoirs of exposed Archaeozoic metamorphic buried hills are mainly developed in four parts including weathered glutenite zone,leached zone,disintegration zone superposed with the cataclasite belt and the cataclasite belt of inner fracture zone,and are controlled by both weathering and tectonic actions.Favorable reservoirs in covered Archaeozoic metamorphic buried hills are mainly developed in the weathering crust superposed with the cataclasite belts and the cataclasite belts of inner fracture zone,and are mainly controlled by tectonic actions.