Storing CO2 With Next-Generation CO2-EOR Technology

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 139717, ’Storing CO2 With Next-Generation CO2-EOR Technology,’ by R.C. Ferguson, SPE, V.A. Kuuskraa, SPE, and T.S. Van Leeuwen, SPE, Advanced Resources International, and D. Remson, US Department of Energy, National Energy Technology Laboratory, prepared for the 2010 SPE International Conference on CO2 Capture, Storage, and Utilization, New Orleans, 10-12 November. The paper has not been peer reviewed. Carbon dioxide enhanced oil recovery (CO2-EOR) has potential for storing significant volumes of CO2 emissions while increasing domestic oil production. The causes of suboptimal CO2 storage and oil-recovery efficiencies by current CO2-EOR practices were examined to determine how a group of advanced or “next-generation” CO2-EOR technologies could increase CO2-storage volumes and oil recovery.  Introduction A six-part method was used to assess CO2 storage and the EOR potential of domestic oil reservoirs. These steps were assembling and updating the major-oil-reservoirs database; calculating the minimum miscibility pressure for applying CO2-EOR; screening reservoirs favorable for CO2-EOR by use of the minimum miscibility pressure and other criteria; calculating oil recovery from applying next-generation CO2-EOR technology; applying updated costs in an economic model; and performing economic and sensitivity analyses to understand how the combined effects of technology and oil prices influence the results of applying next-generation CO2-EOR and CO2-storage technology. Domestic-Oil-Resource Base The USA has a large oil-resource base, on the order of 597 billion bbl of oil originally in place (OOIP). Approximately one-third of this oil-resource base, 204 billion bbl, has been recovered or placed into proved reserves with existing primary- and secondary-oil-recovery technologies. Therefore, 393 billion bbl remains unrecovered as “technically stranded” oil. Much of this “stranded” oil is in east and central Texas (74 billion bbl), the midcontinent (66 billion bbl), and the Permian Basin of west Texas and New Mexico (62 billion bbl). California, Alaska, the Gulf Coast, and the Rockies also have significant volumes of “stranded” oil. Not all of the remaining domestic oil resource is technically amenable to CO2-EOR. Favorable reservoir properties for miscible CO2-EOR include sufficiently deep formations with lighter (higher-gravity) oil. Some of the shallower oil reservoirs with heavier (lower-gravity) oil may be amenable to immiscible CO2-EOR. Impediments to Current CO2-EOR Performance Large volumes of oil are left stranded after primary- and secondary-oil-recovery methods are completed. This includes oil that is bypassed because of poor water-flood sweep efficiency; oil that is physically unconnected to a wellbore; and, most importantly, oil that is trapped as residual oil by viscous, capillary, and interfacial-tension forces in the pore space.