Abstract：Using the finite element method to calculate the gravity anomalies which are caused by a 3D varied-density geological body in its inside and outside spaces involves these steps:1.Calculate both the mass center coordinates and the total mass of the geological body.2.Choose such a closed boundary surface that the distance from each point on the surface to the mass center will be 7-8 times as long as linear dimension of the geological body.3.Replace the gravity values that the geological body causes on the surface by the gravity values that the mass point at mass center whose mass is equal to mass of the body creates on the surface. 4.Solve the boundary problem of Poisson equation with the use of finite element method so as to calculate the gravity anomalies the geological body causes in its inside and outside spaces.Application examples show that finite element method can bring the accuracy of 1-2% when proper boundary and reasonable calculation grid are taken.
吴庆鹏, 葛孝忠. 用有限元法计算变密度三维物体的重力异常[J]. 石油地球物理勘探, 1989, 24(5): 575-591.
Wu Qingpeng, Ge Xiaozhong. Calculating the gravity anomaly of variable density 3-D geological body by using finite element method. OGP, 1989, 24(5): 575-591.
