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 andidentifying complicated fracture/cross beddingsystem (104) by using tri-axial induction logs and wellbore survey/image logdata. 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 solvefor the tri-axial induction response in an arbitrary anisotropic formation dueto the non-orthogonal bedding plane and fracture plane(or cross bedding plane). A mathematical formula is provided relating theconductivity tensor in the tool's reference frame to theconductivity tensor in a reference plane associated with the fracture/crossbedding planes (102). This equation is inverted (103) toyield the conductivity tensor components in the fracture/cross beddingcoordinate system, along with dip and azimuth angles forboth the fracture/cross bedding planes and the tool.