TY - A2的他,金盟——王之盟,方斯楠PY - 2021 DA - 2021/09/24 TI - Borehole-Surface电阻率三维反演方法基于非结构化有限元SP - 5154985六世- 2021 AB -电磁波信号从电磁场源产生感应信号后通过地下介质到达目标地质体。时间和空间分布的规则得到人工或天然电磁场为地下的矿产资源勘探和确定地下的地质构造来解决地质问题。电磁数据处理的目的是抑制噪声,提高信噪比和电阻率数据的反演。反演一直是研究的重点在电磁领域的方法。本文三维borehole-surface电阻率法探讨了基于几何测深的原理,和borehole-surface电阻率三维反演算法的方法提出了在任意表面形貌。正向模拟和计算从偏微分方程和边界条件的三维点电流源的潜在领域感到满意。然后使用非结构化四面体网格离散细分计算面积,可以适应复杂的地下结构和起伏的表面形貌。数值解的准确性很低由于快速衰减的电场急剧点电流源和附近的位置和不同电位梯度。因此,网格密度的定义是在当地的区域,也就是说,附近的源电极和测量电极。网格优化可以有效地减少的影响源点及其附近,提高数值解的准确性。 The stiffness matrix is stored with Compressed Row Storage (CSR) format, and the final large linear equations are solved using the Super Symmetric Over Relaxation Preconditioned Conjugate Gradient (SSOR-PCG) method. The quasi-Newton method with limited memory (L_BFGS) is used to optimize the objective function in the inversion calculation, and a double-loop recursive method is used to solve the normal equation obtained at each iteration in order to avoid computing and storing the sensitivity matrix explicitly and reduce the amount of calculation. The comprehensive application of the above methods makes the 3D inversion algorithm efficient, accurate, and stable. The three-dimensional inversion test is performed on the synthetic data of multiple theoretical geoelectric models with topography (a single anomaly model under valley and a single anomaly model under mountain) to verify the effectiveness of the proposed algorithm. SN - 1687-5869 UR - https://doi.org/10.1155/2021/5154985 DO - 10.1155/2021/5154985 JF - International Journal of Antennas and Propagation PB - Hindawi KW - ER -