基于返揭法的东营凹陷古地热场三维动态模拟

Three Dimensional Dynamic Simulation of Dongying Depression Paleo-Geothermal Field Based on Back Stripping Method

返揭法是利用沉积盆地的大地构造背景、地壳结构、基底热流和沉积层物性参数来确定盆地内各地层的热流及地下温度场分布的一种方法。将基于这一方法研发的软件与基于角点网格建立的三维构造-地层格架模型耦合起来,以东营凹陷的实际数据为例进行了热史反演和古地热场重构,计算并显示了该凹陷在各演化时期的温度和热流三维分布状态。盆地基底古热流是实现盆地地热场模拟的基础边界参数条件,与其他方法相比,返揭法的优点是在计算盆地基底古热流时,可以避开因为构造-岩浆热事件造成的局部古大地热流值异常,而直接采用较稳定的地幔热流值来反演求解。该方法原理简单、计算量较小,只要将该模拟模块与附加地热场模拟模块集成起来,便可完整地实现复杂盆地的古地热场演化模拟。

Back stripping method for crust thermal structure is a method of determining heat flow in layers of basin and the distribution of around underground temperature field, by using geo-structure environment of sedimentary basin, structure of earth, thermal flow value about basin bottom and physical characters of sediments. In this paper, we combine the software with 3D skeleton grid model based on corner point grids, in versioning thermal history and reconstructing geothermal field, taking the data in Dongying De-pression for instance. Finally, it calculates 3D distribution of the temperature field and heat flow about the sedimentary basin in different periods. Compared with other methods, this method can use the more stable mantle heat flow to inverse basin basement paleo-heat flow. It can be avoided the tectonic-magmatic ther-mal event which is caused by the partial exception of ancient,terrestrial heat flow. This method is uncom-plicated principle and relatively small computation. By integrating this modeling module and the module of modeling appended geothermal field, we can realize the complex geothermal field evolution simulation.