Date of Award

6-2012

Document Type

Thesis

Degree Name

Master of Science in Petroleum Engineering (MSPE)

Department

Chemical and Petroleum Engineering

First Advisor

Abdulrazag Y. Zekri

Second Advisor

Dr. Hazim A I-Attar

Third Advisor

Prof. John Chatzis

Abstract

Miscible gas flooding using carbon dioxide is currently investigated as a possible EOR process for a number of United Arab Emirates (UAE) reservoirs. The major factors affecting the implementation of CO2 floods are the availability of CO2 at economic prices and the net utilization ratio of CO2 per barrel of additional oil recovered.Minimizing net utilization requires controlling the high mobility ratio which causes lower sweep. To control the mobility ratio, the Water-Alternating CO2-gas (WAG) technique is proposed.

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 effect of changing the CO2-Water ratio, water salinity, and initial water saturation 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 flooding 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 with ultimate oil recoveries of the CO2-WAG floods failing in between. The optimum CO2-WAG ratio was found to occur at 1:1.

The outcomes of this work should contribute to our understanding of CO2-WAG floods for the selected UAE reservoirs and supports the ongoing R&D efforts made by the operating oil companies in the UAE towards application of CO2-WAG floods.

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