渤海湾盆地西南部古近系滩坝沉积特征及主控因素

Sedimentary characteristics and main controlling factors of Paleogene beach bar in southwestern Bohai Bay Basin

为研究渤海湾盆地西南部古近系东营组和沙河街组滩坝沉积特征及主控因素,开展了岩心观察、薄片鉴定、测井分析、压汞测试等研究,并结合古地貌特征对各类滩坝沉积模式及其差异性进行了综合分析。结果表明:①研究区滩坝类型主要包括砂质滩坝、砾质滩坝、混积滩坝和碳酸盐岩滩坝等4种类型。②物源供给强度、古地貌、古水深及古风浪等4个因素共同控制了滩坝的类型及沉积特征,其中物源供给强度是物质基础,控制了滩坝砂体类型,古地貌与古水深控制了滩坝砂体的厚度和分布位置,古风浪影响了滩坝砂体的展布形态。③砂质滩坝、混积滩坝和碳酸盐岩滩坝储层物性较好,测试产能高,为研究区油气勘探的有利目标。该研究成果可为滩坝储层的油气勘探提供借鉴作用。

In order to study the sedimentary characteristics and main controlling factors of Paleogene Dongying Formation and Shahejie Formation in southwestern Bohai Bay Basin,core observation,thin section identification,well logging analysis and mercury injection test were carried out,and combined with the characteristics of paleogeomorphology,sedimentary models of beach bar and their differences were comprehensively analyzed.The results show that:①There are four types of beach bar,including sandy beach bar,gravel beach bar,mixed beach bar and carbonate beach bar.②The source supply intensity,paleogeomorphology,paleowater depth and paleowind wave jointly control the type and sedimentary characteristics of beach bar.The source supply intensity is the material basis and controls the type of beach bar sand body.The paleogeomorphology and paleowater depth control the thickness and distribution position of beach bar sand body,and paleowind wave affects the distribution form of beach bar sand body.③Sandy beach bar,mixed beach bar and carbonate beach bar have good physical properties and high test productivity,which are favorable targets for oil and gas exploration in the study area.The research results can provide reference for oil and gas exploration of beach bar reservoir.