鄂尔多斯盆地延安地区山西组山2段浅水曲流河三角洲沉积模拟实验研究  

Simulation Experiment of Shallow Meandering River Delta Sedimentation in the 2nd Member of the Shanxi Formation in Yan'an,Ordos Basin

作　　者：曹军 乔向阳[1] 贺永红[1] 周进松 杜永慧 王玺童 田坤 赵子丹 朱耿博仑 罗顺社[2] CAO Jun;QIAO XiangYang;HE YongHong;ZHOU JinSong;DU YongHui;WANG XiTong;TIAN Kun;ZHAO ZiDan;ZHU GengBoLun;LUO ShunShe(Shaanxi Yanchang Petroleum(Group)Co.Ltd.,Xi’an 710065,China;School of Geosciences,Yangtze University,Wuhan 430100,China)

机构地区：[1]陕西延长石油(集团)有限责任公司,西安710065 [2]长江大学地球科学学院,武汉430100

出　　处：《沉积学报》2024年第5期1685-1698,共14页Acta Sedimentologica Sinica

基　　金：陕西延长石油(集团)有限责任公司科技计划项目(ycsy2019ky-A-19)。

摘　　要：【目的】勘探实践表明,鄂尔多斯盆地东南部延安气田主力产气层山西组山2段砂体呈狭长条带状分布,与北部各大气田上古生界砂体大面积连片分布存在显著差异,厘清山西组山2段砂体成因机理对理解该区砂体分布规律具有重要意义。【方法】以盆地东南部山西组山2段为地质原型,利用水槽沉积模拟实验探讨其砂体形成演化过程及控制因素。【结果与结论】平缓坡度与低水流强度是山2段分流河道呈低弯度曲流态的重要因素,水平面的变幅速率是控制山2段砂体纵向延伸的关键因素,砂体的大小及长宽比受岸线及流量变化控制,砂体整体的延伸距离及长宽比分别与水退的幅度和速率成正比。山西组沉积期,在水平面大幅度下降、岸线向湖区长距离迁移背景下,曲流河三角洲前缘砂体延伸较远距离;砂体叠置样式具有“垂向叠置”、“垂向切割”和“侧向迁移”的特征。该认识对山西组砂体分布预测和寻找优质储层具有重要的指导意义。[Objective]Exploration has shown that the sand body of the Shanxi Formation,the main gas producing layer in the Yan'an gas field in the southeastern Ordos Basin,is distributed in a long and narrow strip,which is significantly different from its distribution in the north.It is of great significance to clarify the genesis mechanism of the sand body in the 2nd member of Shanxi Formation for understanding the distribution pattern of sand bodies in the area.[Methods]Taking the 2nd member of the Shanxi Formation in the southeastern basin as the geological prototype,a flume sedimentation simulation experiment was used to investigate the sand formation,evolution process,and control factors.[Results and Conclusions]The gentle slope and low flow intensity of the 2nd member of the Shanxi Formation distributary channel is an important factor in the low sinuosity of the meandering flow state,and the horizontal amplitude rate is a key feature in the longitudinal extension of the sand body,sand size,aspect ratio of the coast,and change of flow control.The extension of the entire distance and length-width ratio of the sand were proportional to the scale and rate of water withdrawal.During the sedimentary period of the Shanxi Formation,the water level dropped significantly,and the shoreline migrated a long distance to the lake area.The water inlet retreated frequently,and the sand in the front of the meandering river delta extended a long distance.The sand superposition style has the characteristics of"vertical superposition","vertical cutting",and"lateral migration".The results are of great significance to the prediction of sand bodies in the Shanxi Formation and the search for high-quality reservoirs.

关 键 词：水槽模拟实验 浅水曲流河三角洲 控砂机制 山2段 鄂尔多斯盆地 

分 类 号：P512.2[天文地球—地质学]