Geologic Characterization For CO₂-EOR Simulation: A Case Study of the Farnsworth Unit, Anadarko Basin, Texas

Abstract

The once prolific hydrocarbon reservoirs of the Pennsylvanian Morrowan sequence of northwest Texas through Southeast Colorado in the United States currently presents an opportunity for Carbon Dioxide (CO₂) enhanced oil recovery (EOR) and carbon sequestration. The Farnsworth Unit (FWU) of Ochiltree County, Texas operated by Chaparral Energy L.L.C. is the site of a CO₂-EOR project using anthropogenic CO₂ and a Southwest Regional Partnership on Carbon Sequestration carbon capture, utilization and sequestration project sponsored by the Department of Energy's National Energy Technology Laboratory. The target reservoir is the upper Morrow sandstone (Morrow-B). Cores and associated thin sections were analyzed to interpret mineralogy, provenance, diagentic history, depositional environment and porosity types. This information, combined with legacy well log data and a new 3D seismic survey, was used to create a fine scale lithofacies based geologic model of the field. Forty-eight wells with permeability and porosity core data were then used for property modeling. In addition, 7 wireline logs were interpreted for porosity and incorporated into the modeling. A variety of geostatistical techniques were used to populate reservoir rock properties. Quality checks were performed to ascertain which geostatistical technique resulted in the best property distribution. The geological model was upscaled for numerical flow simulation. A history match of the waterflood was constructed as the basis for the CO₂-EOR study. The performance of the current CO₂-flood patterns was analyzed and optimized for CO₂ storage and EOR. The lithofacies based geologic model was successfully used to constrain the porosity and permeability distributions. The quality check procedure ensured the well log and core data were honored in the property modeling. The results from the simulation show a great potential for CO₂ storage and prolific oil production from the FWU. This study can serve as a benchmark for potential CO₂-EOR projects in the Anadarko basin.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015