April 10-14, 2016
The Southwest Partnership on Carbon Sequestration (SWP) is one of seven large scale CO2 sequestration projects sponsored by the U.S. Department of Energy, each with the goal of permanently sequestering at least 1,000,000 metric tonnes of CO2. The SWP project is at an active Enhanced Oil Recovery (EOR) project in a mature waterflood in the Farnsworth Unit, Texas, which is undergoing conversion to a CO2 flood. CO2 for this project is anthropogenically sourced from a fertilizer plant in Borger, Texas and an ethanol plant in Liberal, Kansas. Currently, the field has 13 CO2 injectors and has sequestered 386,695 metric tonnes of CO2 between October 2013 and December of 2015. Major goals of the project include optimizing the EOR/sequestration balance, ensuring storage permanence, and developing best practices for carbon storage utilizing man-made CO2.
The Farnsworth Unit converts several inverted 5-spot patterns to CO2 approximately every year since 2011, allowing for rigorous testing of CO2 monitoring technologies since each new set of patterns provides a new opportunity to record zero CO2 baseline data, mid-flood data, and data from fully flooded patterns. The project has acquired multiple data sets for monitoring CO2 plume growth, and storage security including a baseline 42 square mile 3D seismic survey, baseline and repeat 3D vertical seismic profile (VSP) surveys centered on three CO2 injection wells, baseline and repeat cross-well tomography surveys between injector/producer pairs, a borehole passive seismic array to monitor for induced seismicity, distributed temperature arrays to measure variations in borehole temperature, and bottom-hole pressure and temperature sensors to monitor subsurface movement of CO2. The 3D VSP and cross-well data with repeat surveys have allowed for direct comparisons of the reservoir prior to CO2 injection and at eight months into injection, with a goal of periodically imaging the CO2 plume as it migrates away from injection wells. Additional repeat surveys at regular intervals will continue to refine direct CO2 imaging as production and injection data are integrated with newly acquired and interpreted data, and as models are regularly updated.
Additional surface and near-surface monitoring methods are used to evaluate CO2 migration out of the reservoir. In order to verify that leakage of CO2 to the surface does not occur, CO2 soil flux measurements from approximately 90 surface locations are recorded quarterly and compared to the baseline data collected monthly during the first project year. In addition, an eddy covariance tower is located on site to monitor atmospheric CO2 flux and identify any potential point-source leakage (e.g. wellbores). Additional Farnsworth Unit monitoring focuses on groundwater chemistry, reservoir fluids chemistry, and aqueous- and gas-phase tracer studies. The regular CO2 soil and eddy flux, aqueous- and vapor-phase tracer, and groundwater chemistry studies have verified that CO2 (and reservoir fluid) leakage to the surface and/or groundwater has not occurred through December of 2015.
Funding for this project is provided by the U.S. Department of Energy under Award No. DE-FC26-05NT42591. Additional support has been provided by site operator Chaparral Energy, L.L.C
Robert Balch, Richard Esser, and Ning Liu, "Monitoring CO2 at an enhanced oil recovery and carbon capture and storage project, Farnsworth unit, Texas" in "CO2 Summit II: Technologies and Opportunities", Holly Krutka, Tri-State Generation & Transmission Association Inc. Frank Zhu, UOP/Honeywell Eds, ECI Symposium Series, (2016). http://dc.engconfintl.org/co2_summit2/30