渤海湾盆地东营凹陷南坡沙四上亚段滩坝沉积特征及控制因素

根据测井、岩心、分析测试等资料，对东营凹陷南坡东段沙四上亚段滩坝沉积特征展开分析。通过古地貌、古物源分析以及古水深、古水动力恢复，对滩坝砂体沉积展布的控制因素展开研究。结果表明:断陷盆地缓坡带是大规模发育滩坝的底形条件，其中，古坡度是影响滩坝大规模发育的主要因素，该区滩坝多分布在古地形坡度0.5°～2°之间；微观古地形高地及周缘有利于厚层滩、坝沉积；古物源提供滩坝沉积的物质保障，物源供给指数介于0.4～0.6时主要发育砂岩滩坝，介于0.2～0.4时发育混合滩坝。主要采用元素分析法与录井、岩心观察相结合的方法确定了研究区的古水深，沉积环境为滨浅湖，古水动力控制了砂体的横向分异。 

Sedimentary characteristics and controlling factors of beach-bar sandstones of the upper section of the fourth member of Shahejie Formation on the southern slope of Dongying Sag,Bohai Bay Basin

The sedimentary characteristicsof beach-bar sandstones of the upper section of the fourth member of Shahejie Formation on the southern slope of Dongying Sag were analyzed based on logging, coring and testing data. The controlling factors for the sedimentary distribution of beach-bar sandstones were discussed according to palaeogeomorphology, sediment source, paleobathymetry and paleo-hydrodynamics restoration. The results showed that the gentle slope zone in the rift lake basin is themain factor controlling the development of large-scale beach-bar sandstones. The main beach-bar of this area has a topographic gradient between 0.5° and 2°. The micro ancient terrains and their periphery are favorable for the deposition of thick beach-bar sandstones. Sediment sources provide material for the deposition of beach-bar sandstones. When the sediment supply index is between 0.4-0.6, sandstone beach-bar is developed. While the source supply index is between 0.2-0.4, mixed beach-bar is developed. By combining elemental analysis with logging and core observation, the paleobathymetry of the study area was determined, and the depositional environment was a shallow lake environment. Palaeo water force controlled the lateral differentiation of the sand bodies.