Porosity partitioning and permeability quantification in vuggy carbonates

A pilot study of 13 wells in Means oil field of the Permian basin, West Texas, established porosity-permeability relationships for the Permian Queen, Grayburg and San Andres formations. The optimized workflow used borehole image and conventional log processing with calibration to core data. This approach allowed the quantification of porosity and permeability heterogeneity in vuggy carbonate facies in the field. INTRODUCTION Means field was discovered in northeast Andrews County, West Texas, in 1934 with the Humble R. M. Means No. 1 well, Fig. 1. Oil production is from Permian strata, mainly the Guadalupian San Andres, Grayburg and Queen formations, with supporting production from Wolfcampian and Leonardian strata. These formations are predominantly dolomitized marine carbonate platform successions, with the exception of the lower Grayburg, which is a mixed carbonate-siliciclastic reservoir facies. Typical completion strategies are to fracture-stimulate the tighter Grayburg reservoirs and to perforate and acidize the better San Andres reservoirs.