Application of SmartWell Technology to the SACROC CO2 EOR Project: A Case Study

Abstract

Abstract This paper describes a case study of the application of smart field technologies to the SACROC Unit Carbon dioxide Enhanced Oil Recovery (CO2-EOR) project in Scurry County, Texas. A five-well pilot project was implemented in early 2005 to demonstrate the ability of intelligent well down-hole flow control valves to restrict or isolate the production of CO2 from breakthrough zones in production wells and to control the distribution of CO2 injection in injection wells. The objective is to reduce unnecessary cycling of CO2 between injectors and producers, improve sweep efficiency, increase oil production and improve ultimate oil reserve recovery. This is done with cost effective, fit-for-purpose intelligent well systems. The intelligent well technologies and work processes described in this paper are applicable to all EOR/IOR field development plans, and in particular to CO2 WAG developments. The intelligent well technologies as used in this example are applicable to layered, compartmentalized and complex reservoirs, in particular for patterned secondary and tertiary flood processes. Initial results show the CO2 production can be significantly reduced while maintaining economic oil production. The intelligent well equipment also allows selective testing and stimulation of zones within a well without slick line and electric line (e-line) intervention. Introduction CO2 EOR was first attempted in 1972 in large scale at the SACROC unit of the Kelly-Snyder field located in Scurry County, Texas.[1] However, CO2-EOR is currently only used in a few regions of the United States - primarily in west Texas and southern Wyoming. In 2004, the US Department of Energy (DOE) conducted a series of basin-oriented studies to determine the potential for additional economic reserve recovery from the application of CO2-EOR to several mature fields in the United States.[2,3] Six regions were examined: Onshore California, Onshore Gulf Coast, Offshore Louisiana, Oklahoma, Alaska and Illinois. The studies estimated a total potential of over 43 billion barrels of additional oil are recoverable from currently "stranded" oil resources (oil left in the ground following the use of traditional oil recovery practices) by using the latest CO2-EOR technologies. The reports also reviewed the performance of CO2-EOR projects conducted in the six regions during the past 30 years. The DOE study concluded that using CO2-EOR techniques to deplete oil reservoirs has the potential to become one of the most efficient methods for additional crude oil production. The DOE study also concluded that new breakthroughs in CO2-EOR recovery technology could further enhance oil recovery in Texas and other oil producing states. The study noted improved understanding of the potential movement of CO2 within the field gained through integration of core, log, 4-D seismic and cross-well seismic data will help improve enhanced recovery efficiency and increase oil production. The authors of this paper propose that intelligent well technology - that is, the ability to remotely control downhole injection and production without physical intervention, with or without downhole sensing - is extremely well suited to the CO2 EOR process and can potentially improve the efficiency of CO2 EOR floods significantly. This improved efficiency is realized by the ability to better manage the movement of CO2 between wells and through the reservoir. New developments in intelligent well technology to improve flow control and reduce the investment cost of intelligent well technology could make it the next breakthrough technology for improving CO2 EOR performance.