三角洲分流河道及河口坝形成过程的物理模拟

三角洲砂体是已开发油气田中最重要的储集类型之一 ,对该类砂体的形成过程开展物理模型研究以预测储集砂体的分布特征及演变规律具有重要的实际意义。文中以鄂尔多斯盆地三叠系延长统长 6三角洲砂体为模拟原型 ,对三角洲前缘水下分流河道及河口坝形成过程进行了较深入研究。指出长 6三角洲储层主要是在基准面下降过程中 ,由水下分流河道的频繁分汊、交汇、叠合、迁移形成的。由于受到不同期水下分流河道的切割 ,河口坝保持时间较短而欠发育。实验结果与油田地质研究 ( 14口井资料 )对比表明 ,砂体组成及粒度参数的符合率达73% ,砂层厚度分布的符合率达 62 %～ 81% ,沉积微相展布的符合率达 58%。实验过程显示 ,水下分流河道的变迁与湖平面的下降速率及活动底板的运动强度密切相关

PHYSICAL SIMULATION OF FORMATION PROCESS IN DISTRIBUTARY CHANNELS AND DEBOUCH BARS IN DELTA

Sandbody in delta is the most important reservoir type in developed oil gas field. Physical simulation of formation process and inference of the sandbody distribution character are of significance. Based on Trias Chang6 delta sandbody in Ordos basin as simulation antetype, physical simulation of formation process in distributary channel and debouch bar of delta is conducted.The results show that the reservoirs in Chang6 delta were formed by dispart, collection, fold, transfer of underwater distributary channel in the course of datum plane descending. As getting incision of underwater distributary channel in different period,debouch bar keeps short time and low development. Contrast between experimental result and geological research from drilling data of 14 wells shows that the coincidence of sandbody compose and granularity reaches 73%, that of sand layer thickness distubution 62%～81%, and that of sedimentary microfaces distribution 58%. Experimental process shows that variance of underwater distributary channel and declining rate of lake plane are closely related to moving intension of motive soleplate.