基于参考模型的三维电阻率约束反演方法研究

3D constrained electrical resistivity inversion method based on reference model

三维电阻率探测存在反演多解性问题,易造成地质解译困难甚至判断错误。针对该问题,提出将多种地球物理探测手段获得的已知信息构建为参考模型约束施加到电阻率反演方程中的解决思路。以地质钻探获得介质电阻率信息,以地质雷达法获得异常体界面信息,将得到的已知信息映射到三维电阻率反演得到参考模型,在电阻率反演中施加参考模型约束,形成了基于参考模型的三维电阻率约束反演方法,其中携带有已知先验信息的参考模型约束,具有定向引导电阻率反演方向的作用,理论上有助于压制反演多解性。开展相应的数值试验和工程应用,结果表明上述电阻率反演方法实现了对异常体形态、规模、电阻率值等的较好反映,是实现多元地球物理探测信息融合、压制多解性的一条可行途径。

The results of 3D electrical resistivity detection are non-unique, and could easily lead to errors in geological interruption and even misjudgment. A solution is proposed to solve this problem, in which the reference model constraints constructed by the known information from other geological methods are applied to the inversion equation. The electrical resistivity information is gained by the geological drilling, and the boundary information of anomalous bodies is obtained from ground penetrating radar （GPR）. All the known information is mapped into the 3D inversion and then the reference model is obtained, which is introduced to the electrical inversion. Then the 3D constrained electrical resistivity inversion method based on the reference model is got. In this method, the reference model constraints containing the prior information can guide the direction of the inverse progress and make the inversion avoid falling into local optimization. This method can reduce the multiplicity of the inverse solutions in theory. The numerical tests and engineering applications are implemented. The results show that the proposed inversion method can map the shape, size, resistivity of the abnormal body well, and is a practical way to integrate information from multiple geophysical explorations and to suppress the multiplicity.