Sedimentary Characteristics And Reservoir Architecture Of Gravity Flow In The Middle Sub-member Of 3^rd Member,Shahejie Formation In Fan154 District

The paper studies the gravity flow reservoir of 2^nd sand group of the middle sub-member of 3^rd member,Shahejie formation in the Fan 154 Disrict and adjacent area of the Boxing depression.Focused on the genetic types and sedimentary microfacies characteristics of gravity flow,the paper mainly analyzes the reservoir architecture elements,styles and distribution to support the research on geological desserts distribution in gravity flow formed dense reservoirs.The stratigraphic grid is built based on the high-precision sequence stratigraphic division and constaction,which divides the target layers into one quasi-sequence,including two rock strata and seven rock layers within the highstand systems tract.Meanwhile,according to the identification of lithology and bedding characteristics of core observations and descriptions,the target layers of Fan 154 District is formed by the gravity flow deposition alongside the slope of the delta-front,including three main kinds of gravity flow genetic types,sliding gravity flow,sandy debris flow and turbidity deposition,with their dynamic mechanisms,main forming positions and sedimentary structures vary from one to another.The researching area sedimentary system is based on the sliding-caused gravity flow deposition theropy.According to whether the gravity flow channel is found,the sedimentary system can be divided into non-channel subfacies and front-end complex subfacies.Based on the actual enviornment of Fan 154 District,five sedimentary microfacies are developed including sliding,gravity flow channel,debris tongue,channel lob and turbidite sheet.Each sedimentary microfacies has a unique core phase signature and log phase signature with different distributions in sections and plane maps,in which the front-end complex subfacies cover most of the researching area.The gravity flow reservoir architecture configuration scheme is determined ranging from zero level to eighth level.The paper mainly focused on the analysis of the second,the third and the forth levels architecture elements.In the study of the forth level architecture,the paper counts the thickness of mudstone compartment?architecture interface?and sand body?architecture unit?.The study on the third level architecture using well logs establishes mezzanine interpretation analyzing graph,added up to 11 types of lithofacies combination.In the study of the second level,three kinde of seepage barriers are identified through core observations and well logs,which divided the architecture units into 14 different lithofacies types.Co-characterizing the reservoir architecture of gravity flow through outcrop,core,well logs and seismic data,the paper summarizes the overlay relationship in the vertical direction and concludes that the connectivity in the sections is low and the distribution on plane maps consists of three types of modes.