Sedimentary Characteristics And Sand Body Distribution Law Of The Third Member Of Shahejie Formation In The North Of Dongpu Sag

In view of the core problems of sedimentary characteristics and sand body distribution of the sha-3 Member of Shahejie Formation in the northern part of Dongpu Depression,this study was guided by the relevant theories and methods of contemporary sedimentology and sedimentary geology.The sedimentary characteristics and sand body distribution of the sha-3 of Shahejie Formation in the northern part of Dongpu depression were studied in order to provide reliable geological basis for further exploration and development of Shahejie Formation in the study area.On the basis of stratigraphic division and correlation of predecessors and quantitative analysis of the heavy minerals,combined with the gravel distribution characteristics,the provenance system of the sha-3 of Shahejie Formation in the study area was systematically analyzed.The provenance systems can be divided into the eastern,western,northeastern and southwestern provenance systems of the sha-3 Member in study area.In the northeast and southwest provenance systems,the parent rocks mainly came from the Luxi paleo-uplift in the east and the Neihuang palaeo-uplift in the west,mainly magmatic rock series and metamorphic rock series.The provenance direction of the rock series was mainly characterized by inclined transporting to the area in a certain angle in the NW-NE direction and the NNE-NW direction,and the northeast and southwest regions were characterized by provenance mixing.Based on the analysis of the data of drilling,logging,cores and logging,there were systematically discussed the types,characteristics and the distribution of sedimentary facies in the Sha-3 Member by the identification of facies marks in the study area.The sedimentary facies can be divided into the the four sedimentary facies,furthermore,the 9 sub-facies and more than 20 kinds of micro-facies during the Sha-3 Member in the study area.The distribution characteristics of sedimentary facies of the 3 sub-layers of Sha-3 Member were described in detail.Furthermore,the sedimentary model of the Sha-3 Member of was established according to the studied of sedimentary facies and distribution characteristics and closely combined with the analysis of provenance systems and palaeo-geographic pattern.It was clarified that the lower part of the Sha-3 Member was the deltas formation period,and the middle part of the Sha-3 Member was the deltas "westward advance and eastward retreat "and the upper part of the Sha-3 Member was the deltas "westward retreat and eastward advance"in the study area.Based on the above-mentioned sedimentary facies and sedimentary characteristics,the vertical structure characteristics of the fan-delta,braided river delta and meandering river delta distribution channels,dams and shallow sands of the Sha-3 structure are systematically studied in the study area.analysis.And clarified the horizontal structural characteristics of the four sand bodies:"isolated","migration accumulation","continuous" and "maze",identified three types of sand bodies:"stripes","continuous" and "blades",And point out their environmental distribution and possible genesis.In addition,the map of the thickness of sandstone of the Sha-3 Member can provide a scientific basis for the further exploration and development of the Sha-3 sandstone reservoir in the study area.