Abstract: This study addresses the unclear understanding of the sedimentary characteristics and favorable reservoir distribution of the Second Member of the Triassic Baijiantan Formation in the Mahu1 Well Area,as well as the difficulties in reservoir evaluation and reserve calculation.A fine division and prediction of sedimentary facies and favorable reservoir distribution in the Second Member of the Baijiantan Formation were conducted by using integrated data such as logging,well testing,oil testing,and seismic data,and techniques such as sedimentary facies division,correlation of sand body connected well,seismic attribute analysis,seismic acoustic impedance inversion,and stratal slicing.The results indicate that the Second Member of the Baijiantan Formation witnesses the main development of delta front subfacies that can be further divided into sedimentary microfacies such as underwater distributary channels,inter-distributary channels,and sheet sands.Its main body consists of underwater distributary channels that exhibit a tongue-like distribution from north to south.The underwater distributary channels at the delta front serve as favorable reservoir facies,primarily distributed in the central and northern parts of the Mahu1 Well Area.This research provides new insights into the distribution range of favorable reservoirs in the Second Member of the Baijiantan Formation,which is of significant importance for further reservoir evaluation,reserve confirmation,and development in the study area.

Key words: Mahu1 Well Area, Second Member of Baijiantan Formation, sedimentary facies, sedimentary model, reservoir prediction