基于数值模拟的洞庭湖“满盆富砂”沉积过程研究

Study on Deposition Process of "Full Basin and Rich Sand" in Dongting Lake Based on Numerical Simulation

相模式的研究是石油地质勘探与开发的重要方面。洞庭湖作为满盆富砂的重要研究对象,前人做了大量的研究工作,对其沉积体系发育过程的影响因素目前尚不十分清楚,本文基于泥沙水动力学的数值模拟方法,结合现代沉积的泥沙、水动力参数,模拟了单物源和多物源对洞庭湖浅水湖盆的充填过程,分析不同物源条件下沉积过程的水动力状况以及砂体的展布规律,结合洞庭湖地区的卫星图片分析形成"满盆砂"的控制因素。通过沉积过程分析认为,多物源条件是形成"满盆富砂"的重要条件,多物源条件下,物源相互衔接使得盆地水体能量能够维持在较高水平,使三角洲能够分布整个盆地。在单一物源条件下,盆地水体从物源口向盆地逐渐减弱,三角洲分布在物源口处,形成局限的三角洲体系。通过研究为相模式的研究提供了一种新的研究思路与方法,对石油勘探开发具有重要的研究意义。

The study of facies model is an important aspect of petroleum geological exploration and development. It is the main direction of the study of geological deposition. In this paper, based on the research status of Dongting Lake and the related theoretical research of "full basin and rich sand" put forward by predecessors, using the numerical simulation method of sediment hydrodynamics, combining with the sediment and hydrodynamic parameters of modern deposition, the filling process of the shallow lake basin of Dongting Lake by single source and multi source was simulated, and the sedimentary process of the shallow lake basin of the West Dongting Lake was reproduced. The hydrodynamic state and the distribution law of sand body in the deposition process under different material source conditions were analyzed. Combined with the satellite images of Dongting Lake area, the controlling factors of forming "full basin sand" were analyzed. Based on the analysis of sedimentary process, the evolution characteristics and distribution patterns of sand bodies under the control of single source and multi source were studied, and the sedimentary process of "full basin sand rich" mode was successfully reproduced. It was considered that the provenance conditions played an important role in controlling the sedimentary model of sand rich basin. The paper can provide a new research idea and method for the study of facies model, which is of great significance for oil exploration and development.