| 井地2.5维DC反演研究 |
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| 引用本文： | 付德俊.井地2.5维DC反演研究[J].物探化探计算技术,2019(3):365-370. |
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| 作者姓名： | 付德俊 |
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| 作者单位： | 广东核力工程勘察院 |
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| 摘 要： | 开展了不同观测方式的井地2.5D直流电阻率反演研究。①从2.5维直流电阻率满足的边值问题出发,采用变分原理结合节点线性基函数推导了2.5维井地DC满足的积分弱解形式;②构建了二阶最大平滑稳定泛函的2.5维井地直流电阻率正则化目标函数,采用共轭梯度算法对正则化目标函数进行最优化求解,并采用逐步衰减正则化因子的求解策略来提高反演的稳定性;③设计了均匀半空间模型得到的数值解与解析解对比,电位的相对误差在2%以内,阐述正演算法的正确性和高精度。另外,分析了不同观测装置的2.5维井地直流电阻率异常体特征,并对不同观测方式对2.5维井地DC理论数据进行反演研究。研究结果表明,井中数据的引入提高了2.5DC对纵向探测的分辨率能力,同时提高了2.5DC反演有效性以及准确性。
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| 关 键 词： | 井地直流电法 共轭梯度法 有限单元法 最大平滑稳定因子 |
Study on 2.5-d DC inversion of well ground |
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| FU Dejun.Study on 2.5-d DC inversion of well ground[J].Computing Techniques For Geophysical and Geochemical Exploration,2019(3):365-370. |
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| Authors: | FU Dejun |
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| Institution: | (Guangdong Nuclear Force Institute of Engineering Investigation ,Guangzhou 510800,China) |
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| Abstract: | In this paper,the inversion of 2.5D DC resistivity in well ground with different observation modes is carried out. First of all,based on the boundary value problem of 2.5 D DC resistivity,the integral weak solution form of 2.5 D well ground DC is deduced by the variational principle and the node linear basis function. Secondly,the objective function of 2.5-D well ground DC resistivity is constructed for the second order maximum smooth stability functional,and the conjugate gradient algorithm is used to optimize the regularization objective function and the gradual Attenuation regularization factor solution strategy to improve the stability of inversion;Finally,The numerical solution obtained by the uniform half-space model is compared with the analytical solution. The relative error of the potential is within 2%,and the correctness and high precision of the forward algorithm are expounded. In addition,the characteristics of DC resistivity anomalies in 2.5-well wells with different observation devices are analyzed,and the theoretical data of 2.5-well well DCs are inversely studied by different observation methods. The results show that the introduction of well data improves the resolution of 2.5 DC for longitudinal detection,while improving the validity and accuracy of 2.5 DC inversion. |
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| Keywords: | well ground direct current method Conjugate gradient method finite element method maximum smoothness stabilizer |
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