Evaluation of immiscible CO2 enhance oil recovery through the CGI, WAG, and GAGD processes in South Rumaila oil field

Document Type

Conference Proceeding

Publication Date

1-1-2017

Abstract

The South Rumaila oil field was adopted to compare three methods of immiscible CO2 flooding to enhance oil recovery, comparing the Continuous Gas Injection (CGI), Water-Alternative Gas (WAG), and Gas-Assisted Gravity Drainage (GAGD) processes. Unlike the CGI and WAG, GAGD takes advantage of natural segregation of reservoir fluids to provide gravity-stable oil-displacement by injecting gas through vertical wells to formulate a gas-cap which allows oil and water drainage down to the horizontal producers. In this study, an EOS-compositional reservoir simulation was built to evaluate three processes and test their effectiveness to improve oil recovery. For the GAGD process, 20 vertical injectors and 11 horizontal producers were installed for CO2-injection and oilproduction, respectively. The number of vertical producers in the CGI and WAG was set to be 22 wells because the production rate in horizontal wells is approximately twice the rate in vertical wells. Given the remaining oil, the recovery factor by the end of prediction period is 23.72% through the GAGD process. However, the CGI and WAG have resulted in obtaining 12.35% and 11.37% recovery factors, respectively. Consequently, the feasibility of GAGD process to improve oil recovery was demonstrated by obtaining higher recovery factors than CGI and WAG flooding methods.

Publication Source (Journal or Book title)

79th EAGE Conference and Exhibition 2017

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