摘要
本文根据稳恒电流场的Ｆｒｅｃｈｅｔ导数解析式，给出一种井间电阻率成像的非线性反演算法。由于该导数完全由格林函数Ｇ及其梯度表示，因此格林函数的计算是该方法的重要一环。有限元方法被用来计算格林函数Ｇ的数值解，局部函数拟合求导法被用来计算格林函数的梯度，从而得到视电阻率数据进行电阻率成像数值模拟。其结果表明了井间成像的可能性。
Resistivity image can be implemented by a non-linear inversion process us-ing crosshole data. Calculation of the Fre chet derivatives of differential sensi-tivities which establishes the relationship between a small perturbation in themodel and the corresponding change in the datum is an important step in theinversion. An analytical expression of the derivatives,which depends upon theGreen's function and its gradient ,is obtained by use of the self-adjoint differen-tial operator. In this paper, the finite element method and derivative of thepolynomial approach are used to compute the Green's function and its gradientrespectively. The Fre chet derivatives are numerically obtained for resistivityimage and two synthetic experiments are performed.
出处
《物探化探计算技术》
CAS
CSCD
1995年第4期9-17,共9页
Computing Techniques For Geophysical and Geochemical Exploration
