溱潼凹陷南华区块阜三段滩坝沉积特征OA

Based on the regional geological setting of the third Member of the Funing Formation(Fu 3 Member)in the Qintong Sag,a systematic investigation was conducted on lithology,grain size distribution,sedimentary structures,logging responses,and seismic reflection characteristics of the Nanhua Block in the Beihanzhuang Oilfield.Comprehensive analyses indicate that shore-shallow lacustrine beach-bar deposits are well-developed in the Fu 3 Member of the study area,which are controlled by three key factors:provenance,hydrodynamic conditions,and syndepositional faults.The gentle topography and shallow-water environment of the western slope zone provide a favorable sedimentary setting for the development of beach-bar sandbodies.Vertically,the sandbodies exhibit a superimposed pattern of multi-stage bar sands interbedded with mudstones;horizontally,they are distributed in a"strip-like"shape with their long axes parallel to the faults.Multiple syndepositional faults form a special reverse fault assemblage,which not only governs the tectonic framework of the block but also dominates the sedimentary locations and development scales of the beach-bar sandbodies.High-quality beach-bar sandbodies feature good sorting and favorable physical properties,forming an excellent source-reservoir configuration with deep-seated oil-source faults and thus possessing superior hydrocarbon accumulation conditions.Integrating with development practices,the vertical evolutionary characteristics and planar distribution patterns of the beach-bar sandbodies were further summarized.This research provides a reliable basis and direction for the subsequent exploration and development of structural-lithologic composite reservoirs in the outer slope of the Qintong Sag.