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Surfactant flooding carbonate reservoirs

Conference · · Soc. Pet. Eng. AIME, Pap.; (United States)
OSTI ID:6640042

Some of the most difficult yet most attractive targets for EOR are found in the West Texas carbonate reservoirs, where tertiary recovery is complicated by characteristically very low permeability coupled with high hardness and salinity of the reservoir brine. This paper presents data obtained in two well-pair surfactant floods undertaken by Texaco in the San Andres formation, Bob Slaughter Block, Hockley County, Texas. To provide the most data in the least time, a close well spacing and relatively large production/injection ratios were used. For each well pair a different surfactant system was developed, tailored to resist the local aquifer brine salinity and hardness. Consequently, neither system required a preflush. Each test consisted of a large slug of surfactant, followed by biopolymer, fresh water, and lastly formation brine, together with appropriate nonadsorbent tracers. The large slug sizes were intended to allow subsequent designs to be made by interpolation rather than extrapolation. The data provided by these tests and presented here demonstrate that low permeability carbonate reservoirs can be chemically flooded, polymer can be injected and propagated in these reservoirs, without any biodegradation, these systems can mobilize tertiary oil effectively at a chemical consumption near that observed in the laboratory, and two-well tests can provide a quick field evaluation of surfactant systems proposed for largescale use.

Research Organization:
Texaco Inc.
OSTI ID:
6640042
Report Number(s):
CONF-8304162-
Journal Information:
Soc. Pet. Eng. AIME, Pap.; (United States), Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Vol. SPE/DOE 12686; ISSN SEAPA
Country of Publication:
United States
Language:
English