Petrophysical Characteristics and Facies Distribution of Reservoir and Non-reservoir Rocks from the Anadarko Basin, Oklahoma
Using mercury intrusion porosimetry technique we analyzed 103 samples taken from the reservoir and non-reservoir rocks of the Anadarko Basin, Oklahoma. The samples are mainly sandstones, shales, and carbonates, ranging in age from Devonian to Permian and in depth from 404 m to 4,975 m. The objectives of this research are to (1) develop a classification of capillary-pressure curves; (2) establish criteria for identifying petrophysical facies based on capillary-pressure curves; and (3) assess the facies distribution of reservoir and non-reservoir rocks.
The petrophysical parameters used in this study are: median pore throat radius, average pore throat radius, bulk density, apparent skeletal density, apparent porosity, maximum threshold-entry radius (MTER), displacement pressure, entry pressure, pore throat size distribution, pore throat type, and pore throat sorting (PTS). In addition, capillary-pressure curves are classified into six categories based on their shape. The quality of reservoir rocks was estimated using a permeability/porosity plot. Finally, statistical analysis was used to assess correlations between various petrophysical parameters.
The main results are: for reservoir rocks, 38 samples have unimodal pore throat size distribution, 21 samples have bimodal distribution, and 4 do not exhibit any mode distribution; for non-reservoir rocks, 19 samples have unimodal distribution and 21 samples have bimodal distribution. PTS varies between moderate and poor for the reservoir rocks and is predominantly poor for non-reservoir rocks. MTER for unimodal pore throat distribution ranges between 0.0034 – 0.7704 microns for reservoir rocks and 0.0034 – 0.0224 microns for non-reservoir rocks. In this study we demonstrated the links between petrophysical characteristics and facies distribution of reservoir and non-reservoir rocks from the Anadarko Basin, Oklahoma.
New Approaches to Reservoir Characterization and Modeling (AAPG)
2007 AAPG Annual Convention and Exhibition (April 1 - 4, 2007) Technical Program