Research on the sedimentary characteristics of fan delta on the southern steep-slope of Shijiutuo Uplift
The C structure is situated on the steep southern slope of the Shijiutuo uplift in the E3d3 layer.Due to the complexity of its lithology,this study leverages an array of basic data,including drilling records,log data,sidewall coring samples,thin section analysis,and assay reports.Together with a review of the literature and pattern analysis,the research delves into the sedimentary characteristics of the fan delta in E3d3.It examines the sedimentary microfacies,the reservoir properties,and their distribution.The results show that the E3d3 of C1 well comprises a Gilbert-type fan delta,developed in the deep-slope of lake basin.This delta predominantly features fan-delta front sub-facies.The identified micro-faces include nearshore channel microfacies,offshore channel microfacies and underwater distributary interchannel varieties.The nearshore channel microfacies sediments are characterized by coarse grain size,lower textural maturity,primarily consisting of pebbled sandstone and sandy conglomerate.Reservoir has more primary pore,which is the low porosity and low permeability reservoir.In contrast,the offshore channel microfacies is mostly fine grained sediments,with medium-to-fine sandstone that often contains carbonate and exhibits a higher degree of secondary dissolution porosity.The reservoir possess medium level of both porosity and permeability,indicating better physical properties.The study utilizes both seismic stratigraphy and time-frequency analysis techniques to divide the sand bodies longitudinally into four phases of fan bodies.By combining sedimentary simulation and seismic attributes,the distribution range of the four fan bodies has been identified.The research results can serve as a reference and guide for the exploration and development of oil and gas fields in fan delta reservoirs.
万方数据
维普
