【摘要】 针对重力异常反演的现状,采用矩形单元体网格剖分的二度半体组合模型,模拟任意的多层密度界面或形体,实现了重力正演.该建模方法适应性强,适合于实际工作中常见的密度横向变化的复杂模型.使用改进的全局寻优的快速模拟退火算法,对重力异常进行反演,结合这种灵活的密度建模方法,反演过程中只需要反演各矩形单元体的密度参数,即可同时得到地质体的界面或形态以及密度值分布.通过复杂界面和形体的模型试验,证明了方法的效果.在江苏下扬子地质构造复杂区的实际应用说明,在地震等先验信息约束下,该重力反演方法提高了反演精度并减少了多解性,可有效解决古生界泥盆系-志留系目的层分布等地质问题.更多还原

【Abstract】 In accordance with the present state of gravity anomaly inversion, we use the 2.5 dimensional model construction method to divide the underground density structure into rectangle gridded units to simulate density models with arbitrary interfaces or bodies, then perform gravity forward modeling. This model construction is flexible and adaptable especially for the complicated geological models with horizontal varying densities usually appearing in practical situations. We employ the improved very fast simulated annealing algorithm (VFSA), which has obvious advantage of finding the overall optimal solution in inverse problems to perform gravity anomaly inversion. Only the value of each rectangle unit needs to be inversed, the interfaces or shapes and the density distributions can be simultaneously determined during gravity anomaly inversion.Through the complicated model test, this approach is proved effective and practicable. The application in the lower Yangtze area of Jiangsu shows that this inversion approach could increase the accuracy of inversion under the constrained conditions of known seismic data, the objective strata of Devonian-Silurian and related geological problems could be solved efficiently.更多还原