Optimization of CO2 WAG processes in a selected carbonate reservoir - An experimental approach

Mohamed E. Amin, Abdulrazag Y. Zekri, Reyadh Almehaideb, Hazim Al-Attar

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Citations (Scopus)

Abstract

Miscible gas flooding using carbon dioxide is currently being investigated as a possible EOR process for a number of United Arab Emirates (UAE) reservoirs. It has high potential to improve oil recovery in addition to possibly utilizing most of the carbon dioxide emissions from industrial sources. The major factors affecting implementation of CO2 floods are the availability of CO2 at economic prices (generally within 2 - 3 $/MSCF) and the net utilization ratio of CO2 per barrel of additional oil recovered. Typical net utilization of CO2 for well-designed floods vary from field to field but on average has been estimated at 5.5 MSCF CO2 per additional barrel of oil in a US EOR overview study by Broome et al.1 and between 4-6 MSCF/barrel by a more recent study by Jeschke et al.2. At other fields it might be as high as 15 MSCF/barrel or more. Minimizing net utilization requires controlling the high mobility ratio for miscible gas injection which causes lower sweep due to gas channeling and by-passing of the oil in the reservoir. To control the mobility ratio, the Water-Alternating CO2-Gas (WAG) technique is proposed by injecting alternately small solvent [CO2] and water slugs. The slug of water reduces the speed of the solvent and solvent fingering thus improving the mobility ratio of the injected fluids to fluids in place. The objective of this work is to experimentally assess the recovery of oil with CO2 injection in a selected UAE carbonate reservoir. Two types of CO2-flooding experiments were conducted, continuous miscible CO2 injection and CO2-WAG injection using a specialized experimental rig. The effects of changing the CO2-Water ratio and WAG timing on the overall performance of the flood were investigated. All laboratory tests were conducted under controlled conditions of pressure and temperature corresponding to field conditions. Results of this laboratory investigation reveal a general trend of improved oil recovery with increased volume of CO2 inside core samples during the flood process. The observed ultimate oil recoveries range from 52 percent with continuous water injection to 72 percent of the original oil in place with continuous CO2 injection over the full period of the experiment with recoveries of the CO2-WAG floods falling in between. The optimum CO2-WAG ratio was found to occur at 1:2. The outcomes of this work should contribute to our understanding of WAG CO 2 floods for the UAE reservoirs and supports the ongoing R&D efforts made by the operating oil companies in the UAE towards application of CO2-WAG floods

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - Abu Dhabi International Petroleum Exhibition and Conference 2012, ADIPEC 2012 - Sustainable Energy Growth
Subtitle of host publicationPeople, Responsibility, and Innovation
Pages2652-2662
Number of pages11
Publication statusPublished - 2012
EventAbu Dhabi International Petroleum Exhibition and Conference 2012 - Sustainable Energy Growth: People, Responsibility, and Innovation, ADIPEC 2012 - Abu Dhabi, United Arab Emirates
Duration: Nov 11 2012Nov 14 2012

Publication series

NameSociety of Petroleum Engineers - Abu Dhabi International Petroleum Exhibition and Conference 2012, ADIPEC 2012 - Sustainable Energy Growth: People, Responsibility, and Innovation
Volume4

Other

OtherAbu Dhabi International Petroleum Exhibition and Conference 2012 - Sustainable Energy Growth: People, Responsibility, and Innovation, ADIPEC 2012
Country/TerritoryUnited Arab Emirates
CityAbu Dhabi
Period11/11/1211/14/12

ASJC Scopus subject areas

  • Geochemistry and Petrology

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