The Study Of Sedimentary Microfacies Of Es2 In Changfengzhen Strctural Belt, Baxian Depression

Located in south-central Wen’an slope, Changfengzhen structural belt is one of the four nosing structures developed in Wen’an slope and is the payzone with the most exploration potential in this area. Well S88 and Well 96 in the east area has commercial oil flows and been put into production, and commercial oil flow has also been found in Well WG3 in the west area, which indicates good exploration and development potential in Changfengzhen structural belt. Changfengzhen structural belt, however, has the lowest degree of exploration because of un-detailed analysis of distribution features of sandbody, especially oil sandbody, as well as un-accurate analysis of distribution features of sedimentary microfacies, which constrains strongly the hydrocarbon potential evaluation and productivity establishment in Wen’an slope.This paper based on sequence stratigraphy analysis, the Second Member of Shahejie Formation in Changfengzhen structural belt is divided into two sequences and four systematic tracts. The analysis of 12 cored wells integrated with logging data of the targets in this study area resulted in establishment of logging facies chart for targets and identification of distributary channel, natural barrier, and interdistributary channel microfacies developed in delta plain setting as well as underwater distributary channel, underwater natural barrier, and underwater interdistributary channel microfacies developed in delta front setting. Sedimentary facies analysis with seismic data and sandbody distribution features in plane as well as reservoir evaluation with available production data resulted in identification of favorable hydrocarbon potential area in Changfengzhen structural belt.