Discussion On Deposition Process In The Neogene Lower Member Of Minghuazhen Formation In The Bohai Huanghekou Depression,Bohai Sea

As one of the important reservoir sand bodies,the shallow water delta has always been a research object that scholars pay attention to.Predecessors have conducted a lot of discussions on the sedimentary characteristics and controlling factors of shallow water deltas,but there is still a lack of overall understanding of the sedimentary process and dynamics of shallow water deltas.This is also a hot spot in related research in recent years.The lower part of the Neogene Minghuazhen Formation in the Huanghekou Sag is an obvious shallow-water delta deposit.Due to the slow geomorphology of the original basin,shallow lake water and violent water level fluctuations,the control factors for the formation of shallow-water deltas are complex,and sand body prediction is difficult.Therefore,carrying out dynamic simulation research on the deposition process of shallow water delta sand bodies will help clarify the distribution of sand bodies and provide a reference for further sand body prediction.This article takes the lower part of the Neogene Minghuazhen Formation in the Huanghekou Sag in the Bohai Sea as the research object,fully considers the results of previous studies,and comprehensively applies a large number of seismic,drilling and logging data,based on the determination of ancient landforms,ancient provenances,and ancient water depths.,Combined with sedimentary digital simulation software,to simulate and analyze the shallow water delta sedimentation process.In the study,the dynamic evolution process of sedimentation was established,and the control effect of different factors on the deposition process of shallow water delta was analyzed.This can theoretically supplement and improve the understanding of sedimentology,and at the same time provide some references for the understanding of the sedimentary process and characteristics of shallow water deltas,and provide some new research methods and ideas for subsequent research on shallow water delta dynamics,and provide future oil and gas in this area.Provide guidance on the exploration and development of the company.Among the various control factors related to the deposition process of shallow water deltas,this paper selects four parameters such as slope,water level change,hydrodynamic conditions,and source supply rate as the single control factor variables in the sedimentation digital simulation process.Simulate and observe the results.In order to explore the control of the shallow-water delta sedimentation process by factors such as slope,water level changes,hydrodynamic conditions,and source supply rate,the Dionisos sedimentation simulation software was used to control the single variable method,based on the geological data of the Lower Ming Member of the Neogene in the Huanghekou Sag,Bohai Basin Conduct digital simulation research.The results show that:(1)Slopes smaller than conventional shallow water deltas are one of the important factors in the formation of shallow water delta deposits in the study area.Actual calculations and simulations show that the sedimentary slopes of Neogene shallow water deltas in the Yellow River Mouth Sag are between 0.1°and 0.5°;(2)It confirms that the characteristics of the interaction between river and lake sedimentary facies in the study area are caused by repeated changes in water level.The original water depth changes of shallow-water deltas have a decisive influence on the sedimentary morphology and sand body distribution;(3)The formation of shallow-water deltas needs to be driven by hydrodynamic forces,Formed by the combined action of gravity drive;(4)The fine-grained debris material enters from the gentle source exit,and the transport of high-load,low-density,long-term low-energy and stable water current is one of the important factors for the formation of shallow delta deposits.