断陷湖盆缓坡带古河道定量恢复方法及油气地质意义：以霸县凹陷文安斜坡东营组为例

河流沉积砂体定量表征是油田高效勘探开发的重要基础。文章综合利用定量岩心分析、测井相分析、定量地震沉积学和三维地震剖面识别方法，对霸县凹陷文安斜坡东营组古河道砂体厚度，河道（带）宽度，（满岸）河道水深等河流参数进行了定量化计算。研究表明，文安斜坡东营组发育北部苏桥、中部文安和南部长丰镇三个物源输入口，河流呈NEE-SWW向分散于文安斜坡带，其中河道带宽度（w）为1.04~2.61 km，平均宽度（wcb）为1.71 km；主河道宽度（W）为15.2~179.6 m，平均宽度（Wc）为84.4 m；主河道沉积水深（D）为1.34~5.21 m，平均水深（Dc）为3.29 m；主河道满岸水深（Dmax）为2.35~9.15 m，平均满岸水深（Dmaxa）为5.77 m；主河道沉积厚度（H）为2.15~8.32 m，平均厚度（Hc）为5.25 m，河道长度（L）为18.5~28.2 km，平均河道带长度（Lcb）为25.1 km，流向（A）为40°~65°。确定文安斜坡东营组发育辫状河沉积，斜坡东侧中外带为主要的砂岩卸载区，河流以垂向挖掘性河流为主，侧向迁移为辅，河道砂岩平面呈“条—带”状。文安斜坡西侧内带以侧向迁移河流为主，下蚀作用为辅，河道砂岩呈“席—带”状。东营组河道砂岩具有“下生上储”的有利成藏条件，具有良好的岩性、构造—岩性圈闭（油气藏）勘探前景。

Restoration and Characteristics Analysis of Paleochannels in GentleSlopes of A Rift Basin: Dongying Formation ofBaxian Sag,Bohai Bay Basin

Quantitative analysis of fluvial sand body is important for efficient oilfield exploration and development. In this paper, quantitative core analysis, well logging facies analysis, quantitative seismic sedimentology, and 3D seismic profile identification are used to quantitatively calculate the thickness of paleochannel sand body, width of channel (belt), depth of channel and other river parameters of Dongying formation in Wen’an slope of Baxian sag. The analyses reveal that there are three provenance entrances in Dongying formation of Wen’an slope, Suqiao in the north, Wenan in the middle, and Changfengzhen in the south. The rivers flowed on the Wen’an slope in NEE-SWW directions. The width (W) of the channel belt is 1.04-2.61 km, and the average width (wcb) is 1.71 km; the width (W) of the main channel is 15.2-179.6 m, and the average width (Wc) is 84.4 m; the depth (D) of the main channel is 1.34-5.21 m, and the average depth (Dc) is 3.29 m; the full depth (Dmax) of the main channel is 2.35-9.15 m, and the average full depth (Dmax) is 5.77 m; the thickness (H) of the main channel is 2.15-8.32 m, the average thickness (Hc) is 5.25 m, the length of river channel (L) is 18.5-28.2 km, the average length of river channel belt (Lcb) is 25.1 km, and the flow direction is 40°-65°. It is considered that Dongying formation of Wen’an slope are braided river deposits. The outer zone of the slope is the main unloading area of sandstone, the river is dominatly vertically excavated and supplemented by lateral migration, and the plan view of channel sandstone is “strip belt”. The inner zone of Wen’an slope is dominated by laterally migrating rivers, supplemented by erosion, and channel sandstone occurs as a sheet blanket. The channel sandstone of Dongying formation has the sedimentary conditions of “lower generation and upper reservoir”, and the development of lithologic and structural lithologic reservoirs has a promising prospect for oil and gas exploration.