Predicting spatial distribution of critical pore types and their influence on reservoir quality, Canyon (Pennsylvanian) Reef reservoir, Diamond M field, Texas

Abstract

This study examined the stratigraphic architecture, depositional and diagenetic histories, and resulting reservoir characteristics that have influenced the occurrence, distribution, and quality of flow units in the Diamond M field, Scurry County, Texas. The study area is located in the Midland Basin. The field has production from the Canyon (Pennsylvanian) Horseshoe Atoll carbonate buildup. Recent drilling in the Diamond M field was done to evaluate ways to improve recovery by water flooding. Classification of depositional texture based on detailed petrologic and petrographic studies on three cores was done. Subsequent genetic classification of pore types by thin section petrography revealed three dominant pore types: intramatrix, moldic, and vuggy. The reservoir was zoned according to dominant pore type and log signatures to evaluate correlations at field scale by using neutron logs. Equations determined from core analyses provided equations used for estimating porosity and permeability, which were used to develop a ranking scheme for reservoir quality based on good, intermediate, and poor flow units at field scale. Ultimately slice maps of reservoir quality at a 10 ft interval for a 150 ft section of the Canyon Reef reservoir were developed. These reservoir quality maps will provide a useful tool for the design and implementation of accurate and profitable development programs.