Method for reservoir fracture and cross beds detection using tri- axial/multi-component resistivity anisotropy measurements

摘要

The invention is a method for inverting reservoir bi-axial anisotropy and identifyingcomplicated fracture/cross-bedding system (104) by using tri-axial inductionlogs and wellbore survey/image log data. An inversion method is disclosed thatuses all nine components that can be measured by tri-axial induction tools (101),plus borehole azimuth and deviation data, to solve for the tri-axial inductionresponse in an arbitrary anisotropic formation due to the non-orthogonal beddingplane and fracture plane (or cross bedding plane). A mathematical formula isprovided relating the conductivity tensor in the tool's reference frameto the conductivity tensor in a reference plane associated with the fracture/crossbedding planes (102). This equation is inverted (103) to yield the conductivitytensor components in the fracture/cross bedding coordinate system, along withdip and azimuth angles for both the fracture/cross bedding planes and the tool.