CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir
The application of cyclic CO2, often referred to as the CO2 Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO2 Huff-n-Puff process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital-intensive miscible projects. Texaco Exploration & Production Inc. and the U. S. Department of Energy have teamed up in an attempt to develop the CO2 Huff-n-Puff process in the Grayburg and San Andres formations which are light oil, shallow shelf carbonate reservoirs that exist throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected sites for this demonstration project are the Central Vacuum Unit waterflood in Lea County, New Mexico and the Sundown Slaughter Field in Hockley County, Texas. Miscible CO2 flooding is the process of choice for enhancing recovery of light oils and already accounts for over 12% of the Permian Basin's daily production. There are significant probable reserves associated with future miscible CO2 projects. However, many are marginally economic at current market conditions due to large up-front capital commitments for a peak response, which may be several years in the future. The resulting negative cash-flow is sometimes too much for an operator to absorb. The CO2 Huff-n-Puff process is being investigated as a near-term option to mitigate the negative cash-flow situation--allowing acceleration of inventoried miscible CO2 projects when coupled together. The CO2 Huff-n-Puff process is a proven enhanced oil recovery technology in Louisiana-Texas Gulf-coast sandstone reservoirs. Application seems to mostly confine itself to low pressure sandstone reservoirs 7 . The process has even been shown to be moderately effective in conjunction with steam on heavy California crude oils. A review of earlier literature provides an excellent discussion on the theory, mechanics of the process, and several case histories. Although the technology is proven in light oil sandstones, it continues to be a very underutilized enhanced recovery option for carbonates. However, the theories associated with the CO2 Huff-n-Puff process are not lithology dependent. It was anticipated that this project would show that the application of the CO2 Huff-n-Puff process in shallow shelf carbonates could be economically implemented to recover appreciable volumes of light oil. The goals of the project were the development of guidelines for cost-effective selection of candidate reservoirs and wells, along with estimating recovery potential.
- Research Organization:
- Federal Energy Technology Center, Morgantown, WV, and Pittsburgh, PA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC22-94BC14986
- OSTI ID:
- 2216
- Report Number(s):
- DE-FC22-94BC14986-18; ON: DE00002216
- Country of Publication:
- United States
- Language:
- English
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CO{sub 2} huff-n-puff process in a light oil shallow carbonate reservoir. Annual report, January 1, 1996--December 31, 1996
CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir