缓坡浅水辫状河三角洲沉积模拟实验研究

Study on Sedimentation Simulation Experiment of Gentle-slope Shallow Braided River Delta

缓坡浅水辫状河三角洲砂体是重要的储集类型之一,且蕴含着丰富的油气资源,对该类砂体形成、分布及演变规律进行研究具有重要的实际意义。文中以鄂尔多斯盆地苏里格地区二叠系中统下石盒子组盒8段为模拟原型,应用沉积模拟实验技术,论述了辫状河三角洲的形成过程和沉积微相特征,探讨了影响辫状河三角洲形成及演变的控制因素,揭示了平缓构造背景下大面积砂岩形成机理。综合原始地质模型和实验认识,建立了实验条件下苏里格地区盒8段辫状河三角洲沉积模式。

The sandbody of gentle slope shallow braided river delta is one of the most important reservoir type, which is rich in oil and gas resources, so it has practical significance to study the formation, distribution and evolution of this type of sandbody. On the background of He8 section of Xiashihezi Formation of Permian system in Ordos basin, the formation process of braided river delta is reconstructed, and the characteristics of sedimentary micro-facies are discussed by using the technology of simulation experiment. The systematic study on the main controlling factors of the formation and evolu- tion of braided river delta is completed, and the formation mechanism of large area sandstone under the background of gentle structures is revealed. The study results show that the basement Subsidence, relative lake level changes, flow, sediment supply and so on are the main controlling factors of the formation and evolution of braided river delta; the low slope, abundant sediment supply, strong currents, frequent changes of lake-level and catchment of multiple water systems are the amin reasons for the distribution of large area sandstone. Based on the initial geological pattern and the understanding of simulation experiment, the sedimentary model of the braided river delta of He8 section in Sulige area is set up under experimental condition.