起伏地形下的井中激电井-地方式并行反演研究

The borehole induced polarization（IP） method is one of the most effective borehole geophysical prospecting methods to detect deep mineral resources. Due to the measuring point on the ground，the borehole-ground IP method can get more observation data and underground information, so that we can conduct 3D inversion better. However, the 3D borehole IP inversion could have multiple solution，and also requires large memory storage and long computing time. These factors become the crux which restrict the 3D inversion of the borehole-ground IP method from theory to practical application. For this problem, this program proposes one 3D parallel inversion method based on inequality constraints for the borehole-ground IP method. The program adopts the MPI parallel technology to improve the calculation efficiency and imposes constraints to neutralize the non-uniqueness directly. Meanwhile, this program obtains experiment data of regular volume through flume experiment. With the inversion calculation of theoretical model, the program studies the influence on the 3D borehole IP inversion by different imposing way of constraints, and also anaylzes the calculation efficiency under different parallel strategy. According to the flume experiment data, this program establishes and consummates the processing and interpretation model for the borehole-ground IP data，which provides the theoretical basis and guidance for our 3D inversion and practical work of the borehole-ground IP method.

井中激发极化法是寻找深部矿产资源最有效的井中物探方法之一，井中激电井地方式由于测点在地面，可以得到更多的观测数据，获取更多的地下信息，能够更好的进行三维反演，然而三维井中激电反演存在多解性、内存需求大且计算时间长，是制约井中激电井地方式三维反演由理论走向实际应用的关键。针对这一问题，本项目提出带不等式约束的三维井中激电井地方式并行反演方法，该项目采用MPI并行技术提高计算的效率；在反演目标函数中直接施加约束条件压制非唯一性；利用水槽实验获得井中激电井地方式规则形体的实验数据。通过理论模型的反演计算，研究分析不同的约束条件施加方式对三维井中激电反演结果的影响和不同的并行策略下的反演计算效率，结合水槽实验数据建立和完善井中激电井地方式实际资料的处理和解释模型，为我国井中激电井地方式的三维反演与实际工作提供理论依据和指导。

针对非结构化网格剖分困难的情况，引入了三维有限元网格生成器Gmsh，研究了以交互式的图形界面方式或在ASCII文本文件中使用Gmsh自己的脚本语言两种方式实现非结构化网格生成与加密方法；完成了起伏地形下的三维电阻率法、三维井中激电井地方式并行正演算法；完成了基于光滑模型约束的三维电阻率法、三维井中激电井地方式并行反演算法；完成了以最小支撑约束、最小梯度支撑约束为稳定因子的一类聚焦反演方法；研究并分析了不同的约束条件施加方式对三维井中激电反演结果的影响；研究不同的并行策略下的反演计算效率；对反演过程中的聚焦因子的选择与稳定因子的梯度求解进行了研究；研究了几种典型起伏地形下的地电模型的异常特征，并与平坦地表条件下的地电模型的模拟结果进行对比。