Restored Prototype Basin Of The Thickness Of The Fourth Member Of The Shahejie Formation And Kongdian Formation In Huimin Depression

In order to restored prototype basin of the fourth member of the Shahejie formation and Kongdian formation in Huimin depression, this paper based on the structural evolution and faults system research, and the sufficiently using of core, well logging and seismic data, is to focus on studies of calculating erosion amount and restoring the thickness of prototype basin, so as to probe the formation, reconstruction and its effect on oil accumulation of basin and provide geologic evidence for the distribution characters of deep reservoir which were revealed.A new way to restore the erosion amount of prototype basin is presented under the control of wave analysis method. By means of wave analysis, the main wavy cycle of 57, 27 and 7.5 Ma which reflecting the formation and development of Huimin depression are obtained, and the range of erosion amount is limited by 7.5Ma wavy cycle that reflecting the erosion status of each sedimentary interval-face firstly, then according to different geologic and data condition, the erosion amount is fine calculated with four methods, such as sedimentary rate, optimum estimation by porosity data, vitrinite reflectance and stratigraphic contrast method, on the basis of calculated sedimentary rate of Huimin depression. In the control of wave analysis, consulting the analysis of geologic history of deposition and structural evolution, the erosion amount is obtained by the weighted average of multi-perspective methods exactly.The erosion status of deep strata is related to the structural and sedimentary revolution of Huimin basin from Paleocene to Eocene, and the NE trending is the primary direction of its erosion amount contour which is accord with the structural movement from late Mesozoic to early Cenozoic. The regions with high erosion thickness of Es4 and Ek are centralized on the edge of depression or faults; the erosion amount of Ek, ranges of 200m to 1000m,with the region valuing over 1000m in the Linnan faults; and the erosion thickness of Es4, is mostly from 100m to 400m, which has the largest amount over 500m in both the edge of the southern slope and the central upheaval zone.The thickness contour of Ek and Es4 in prototype basin are synthesized from ancient structural analysis of Cenozoic period, the erosion amount and the original thickness which is restored from rudimental thickness. The results show that, during the Ek2 period, Huimin depression is the continental fault basin of the NNE trending, with the strata of Ek2 overlapping to the southern slope, of which central sedimentation are mostly located in the northeast of Zizhen region, the west of Linfanjia region and the northwest of Yangxin region; the depression-controlled faults, that are Zizhen and Yangxin faults with the NE trending, played further obvious role in the Ek1 period, and the strata of Ek1 are mainly sedimentated in the northeast of Linnan region and Zizhen region, the south of Yangxin region and the north of Linfanjia region, which are overlapped not only the southern slope but the northwest direction; the sedimentary strata of the east region is more thicker than those of the west region during the Es4 period, and the deepest regions are in the centre of each sags.