Patent ID: 8360146

Claim:
A method for detecting fault or cross-bedding planes, hereinafter, called fault planes, in subsurface petroleum reservoir formations with bi-axial anisotropy, meaning one axis perpendicular to the formation's bedding planes, the other perpendicular to the fault planes, from conductivity/resistivity measurements made in a well using a multi-component, tri-axial induction well logging tool, comprising: (a) expressing a formation conductivity tensor with components as measured by the well logging tool, wherein each component of said tensor is expressed as a combination of the conductivity components: (i) conductivity normal to bedding plane σ nb , (ii) conductivity parallel to bedding plane σ pb , (iii) conductivity normal to fault plane σ nf (iv) conductivity parallel to fault plane σ pf ; (b) inverting the expression for the formation conductivity tensor to obtain σ nb , σ pb , σ nf , and σ pf from the measured conductivity data; and (c) detecting one or more fault planes from indications of anisotropy in the inversion results.