Application of Borehole Imaging to Evaluate Porosity and Permeability in Carbonate Reservoirs: From Example from Permian Basin

Vivek D. Chitale¹, Clive Johnson², Hunter Manley³, David Entzminger⁴, and Lyn Canter^5
1Reservoir Evaluation Services, Halliburton, Houston, TX
²Reservoir Evaluation Services, Halliburton, Ft Worth, TX
³Reservoir Evaluation Services, Halliburton, Midland, TX
⁴Permian Basin, Whiting O&G, Midland, TX
⁵Exploration and Production, Whiting O&G, Denver, CO

This paper presents a case history of applying modern borehole image interpretation technique to carbonate reservoir evaluation in a development well from the Permian Basin. The new borehole image interpretation technique was developed specifically to evaluate the porosity and permeability of carbonate reservoirs by integrating the high resolution data from an electrical borehole image log with the conventional wireline logs.

As shown in the paper, the Xtended Range Micro-Imager (XRMI) with improved signal to noise ratio and expanded dynamic range, was able to generate very high resolution borehole images showing millimeter size features in the fabric of carbonate beds. The micro-conductivity signal was then analyzed with the help of a newly developed software technique that first equates the total signal with total porosity that is then resolved into fractions correlatable with micro-, primary- and secondary porosity. The new technique of image interpretation uses published models to equate carbonate rock types and their porosity types with permeability.

Integrated analysis of XRMI and other logs from a well drilled in a Wolfcamp carbonate reservoir in Permian Basin of USA shows that the “facies and layer boundaries, the internal fabric of the carbonates, and the estimates of different porosity fractions and permeability determined by using the new imager and the new interpretation technique closely follow the core descriptions and laboratory analysis of porosity and permeability. These results are encouraging as these correlation(s) should be applicable in future to the newly drilled wells in the similar geological facies in the region where there is no core control.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas