الفهرس Only 14 pages are availabe for public view
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Abstract
A large number of mature water flooded oil reservoirs are nearing their economic limit of oil production. For these reservoirs, additional production will come from tertiary oil recovery processes, most likely miscible carbon dioxide flooding. The studied reservoir has produced by primary recovery from 1959 to 1971 and by secondary recovery (water flooding) from 1971 up to date. Recently, the reservoir pressure and oil production have decreased significantly, while water cut has increased. Therefore, tertiary recovery is needed for this reservoir. This research project is twofold: first, studying the technical feasibility of applying CO2 flooding in the studied reservoir. Second, evaluating the economical feasibility of CO2 flooding. The impact of changing oil and CO2 prices on the project economics was also investigated. This work was intended to select the best technique of CO2 injection, in terms of the increase in oil recovery and net present value. A three dimensional multiphase model has been developed using ECLIPSETM software. Many runs were made for three different injection techniques, which are continuous water flooding (base case), continuous CO2 injection and water alternative gas (WAG). Two scenarios are studied in WAG technique where one and two cycles are used. Different slug sizes and injection rates were used. The net present value (NPV) was calculated for each injection rate for the three techniques. Results indicated that CO2 flooding is technically feasible in this reservoir. The optimum slug size is 48% pore volume in case of continuous CO2 injection and WAG technique (for the two scenarios). The oil recovery factor increased from 50 % in the base case to 68 % in case of employing WAG technique (two cycles). Economic study indicated that the optimum injection rate was 25MMscfd in all techniques. Second scenario of WAG (two cycles) technique would be the best injection technique for this reservoir. The NPV in this case is equal to $409 million. The sensitivity analysis revealed that the oil and CO2 prices have significant effect on the economical feasibility, and also on the selection of the best technique in the application of CO2 flooding.