IMPLICATIONS FOR UNCONVENTIONAL HYDROCARBON RESERVOIR QUALITY: PORE SYSTEM ARCHITECTURE AND ANALYSIS OF THE CANEY SHALE

The Mississippian Caney Shale of the Ardmore Basin, southern Oklahoma, is an emerging unconventional hydrocarbon play. Due to the unpredictable production and limited information of the Caney Shale, we are evaluating its reservoir quality by quantifying the pore system architecture (e.g., pore type, size, shape) within a core-based stratigraphic framework. Porosity and pore system architecture are critical in evaluating reservoir potential, as they directly impact the quality of reservoirs. Preliminary findings utilizing a scanning electron microscope (FE/SEM) demonstrate a variety of nanometer- to micrometer-sized pore types, including organic matter pores, a variety of intraparticle, intercrystalline, and interparticle pores, as well as intraparticle/intercrystalline pores within clay. Digital image analysis was used to quantify two-dimensional pore geometrical parameters (e.g., size and shape). Detailed core analysis was also used to identify facies types and their tie with pore system architecture. A variety of mixed carbonate-siliciclastic facies types are identified, with the main types being low energy mudstone and siltstone, and carbonate groups that interpreted as more high energy event deposition (turbidites, debris flow deposits, hybrid events) within the low energy background sedimentation on a slope to ramp system. These three facies groups appear to contain similar pore types, but variabilities are observed in the pore geometrical data and when tying these data with porosity and permeability at a facies group scale. These observations suggest variable pore system architecture and the resultant petrophysical response in the different facies, as well as the potential of estimating reservoir quality using pore geometrical data. These results suggest that consideration of the variable depositional distribution patterns and relating pore architecture and reservoir quality of these facies, can be valuable for characterizing reservoir heterogeneity at multiple scales.