基于烃类垂向微渗漏的地球化学场数值模拟

Numerical Simulation of Geochemical Field Based on Hydrocarbon Vertical Micro-seepage

基于烃类微渗漏基本理论和连续介质假设,总结了近年来地球化学勘探领域主流的关于烃类微渗漏机制的假说;根据其中最为普遍接受的烃类气体以胶体大小的微气泡做布朗运动向上运移为主的微渗漏机制,利用多孔介质流体动力学以及能量守恒定律建立了定量描述烃类微渗漏的数学模型;采用构建单层和多层积木块理想地层介质模型叠加的方法对典型地质条件进行了划分和组合;建立了描述地层介质模型内部烃类垂向微渗漏过程的定量方程,即一类反应-对流-扩散偏微分方程,进行了"油气藏中烃类组分垂向微渗漏和异常形成动态过程"的数学描述和模拟,并将上述过程付诸于典型实践区——鄂尔多斯盆地花豹沟油气藏进行模型的数值验证与实例分析,得到与实际勘探数据相一致的结果。研究成果为复杂条件下油气运移定量地球化学场数学模型的建立提供了一种新的思想和具体数学方法。

Based on the theory of hydrocarbon micro-seepage,this paper summarized the major mechanism of hydrocarbon micro-seepage hypothesis on geochemical exploration areas in recent years.According to one of the most commonly accepted mechanism of micro-leakage that hydrocarbon gas do Brownian motion in the form of colloidal micro-bubbles upward,this study established a numerical model of hydrocarbon micro-seepage with the theory of Porous media fluid dynamics and energy conservation,and simulated the dynamic process of vertical micro-leakage of hydrocarbon components and the abnormal formation.Combined the typical geological medium of Huabaogou oilfield in Ordos Basin with the ideal stratigraphic building block models,the result reveals that the process simulated by computer has the same trend as the real reaction and provides a specific idea for the construction of quantitative mathematical model of hydrocarbon migration under complex geochemical field.