Miscible CO2 injection is the second largest contributor to global enhanced oil recovery, as it has successfully undergone extensive laboratory tests and field applications for recovering residual oil left behind after waterflooding. Prolific incremental recoveries have been obtained for some fields. Although miscible CO2 injections generally have excellent microscopic displacement efficiency they often result in poor sweep efficiency. In order to address sweep problems and maximize recoveries, other schemes of gas injection have been developed. Two such processes are water-alternating-gas (WAG) and simultaneous water-and-gas (SWAG) injection. WAG and SWAG have been successfully used to minimize poor sweep. Improved gas utilization and oil recovery have been reported for SWAG injection at Joffre Viking, Kapurak River, and Rangley Weber fields.
There are very little published data evaluating the performance of simultaneous water and gas injection under miscible conditions and very little published data exists that compares enhanced recovery processes conducted under consistent experimental conditions. This is especially true when the gas is CO2. In this work a sequence of experiments were conducted to evaluate core flood behavior of Continuous Gas Injection (CGI), 1:1 Water Alternating Gas (WAG) with a slug size of 0.25 pore volumes, and Simultaneous Water-and-Gas (SWAG) injection at four fg values. The experiments were conducted at rock wettability, flow rates and pressures that were as consistent as possible in order to make meaningful comparisons. After 2 PV of CO2 injection the SWAG flood with fg = 0.4 recovered about 0.9692 of waterflood residual oil. CGI had the second best recovery of about 0.8998 followed by WAG with 0.8602. The SWAG flood with fg = 0.6 recovered about 0.8300 of waterflood residual oil and SWAG with fg = 0.8 and fg = 0.2 recovered about 0.7507 and 0.7253 respectively. The gas utilization was the least for SWAG with fg = 0.4 at 15.54 Mscf/bbl followed by CGI with 16.13 Mscf/bbl. The remaining experiments utilized over 17.20 Mscf/bbl.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-04252011-214015 |
| Date | 26 April 2011 |
| Creators | Shetty , Shrinidhi |
| Contributors | Kam, Seung, Rao, Dandina, Hughes, Richard |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-04252011-214015/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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