Reservoir Characteristics Of Shahejie Formation In Tangzhuang Area Of Huimin Depression

The stratigraphic framework and reservoir distribution system in Tangzhuang area, west of Huimin Depression, haven't been established because there are so many faults and different kinds of reservoir. And the exploration and exploitation of this area are also confined by these reasons for a long time. Due to these above questions, reservoir characteristics of Shahejie Formation have been studied systematically and precisely here by using geological, seismic and logging data.Firstly, sequence and systematic architecture have been classified by identifying unconformity, surface of interruption , sedimentation types of inner cycles and degrees as well as the overlying pattern with the method of sequence stratigraphy and sedimentological theory. And we devide the studied formation into five Three-degree sequences which accord with Es1 member to the third submember of Es3. Then sublayers have been divided and correlated by analysis of sedimentary cycles-thickness. Secondly, combining with core observation, single well facies analysis, slice and scanning electron microscope analysis as well as well logging, sedimentary facies of Shahejie Formation have been divided and their types and identification marks also have been summarized. The vertical and planar distributions are described as follows: in the vertical direction, offshore-mere facies, delta plain facies and delta front facies chiefly exist from Es1 member to Es3 member, whereas in plane, offshore bar facies are parallel to the fault line trending in northeast to southwest and channel microfacies is almost vertical to the fault line trending (northwest to southeast). This shows that the material come from the north and northwest of the studied area. Thirdly, further study on reservoir characteristics of Shahejie Formation, according to coring, slice and scanning electron microscope data, has indicated that the major type of reservoir space is primary porosity. And their accumulating property is affected by such factors as lithofacies, rock types, structure movements and diagenesis, among which lithofacies and diagenesis are in the majority. Fourthly, by systematic researches on micro-pore structures, vertical and planar distribution of reservoirs and their changes, and practical testing and producing test data, we has predicted favorable accumulating facies belt. The offshore bar facies in Es1 member, distributary channel microfacies in Es2 member, as well as submarine distributary channel and mouth bar microfacies in Es3 member, are of relatively good accumulating property. Finally, comprehensive researches on sedimentary facies, oil sources, structure, reservoirs and cap formation have revealed that fault, facies of sedimentary rock and cap formation(interlayer) are the major factors dominating hydrocarbons distribution in studied area. All of our above findings could provide favorable evidence for the selection of important faulted block and further regulation of exploitation.