A quantitative approach to characterize porosity structure from borehole electrical images and its application in a carbonate reservoir in the Tazhong Area, Tarim Basin

For a carbonate reservoir that has low porosity, its validity cannot simply be measured by its total porosity. Therefore, one must find more-effective porosity parameters to indicate reservoir validity. Two parameters that reflect the porosity spectrum's shape are proposed in this paper to characterize the porosity structure from borehole electrical images. One is the length of the right-porosity spectrum (LRPS), and the other is the root mean square (RMS) of the right-porosity spectrum (RMSRPS). Subsequently, the validity of a carbonate reservoir was considered by use of these two parameters. The logging evaluation, processing, and interpretation of multiple wells in a fractured/vuggy reservoir with low porosity in the Tarim Basin indicate that these two parameters reflect the variation of pore structures better than conventional methods, and they agree better with the well-test results. © Copyright 2016 Society of Petroleum Engineers.