Wells – Processes – Distinct – separate injection and producing wells
Reexamination Certificate
1999-12-17
2001-08-07
Suchfield, George (Department: 3672)
Wells
Processes
Distinct, separate injection and producing wells
C166S305100, C507S259000, C507S904000
Reexamination Certificate
active
06269881
ABSTRACT:
FIELD OF INVENTION
The present invention is directed to enhanced oil recovery. More specifically, the present invention is directed to enhanced oil recovery of a waxy crude using alkylaryl sulfonate surfactants.
BACKGROUND OF THE INVENTION
Alkylaryl sulfonates have been recognized as promising for enhanced oil recovery by surfactant floods. They can be manufactured in large quantities and can generate low interfacial tensions with oils under favorable conditions, see Malmber, E. “Large scale sulfonates for laboratory studies in tertiary oil recovery:preparation and related studies, final report” USDOE report No. FE-2605-20, May 1979. Much of the efforts have been to develop unique, monomerically pure surfactants for light oils, see Malmber, E. W. et. Al., “Characterization and oil recovery observations on a series of synthetic petroleum sulfonates,” SPEJ (April 1982) 226-236; and Comberiati, J. R., et. Al., “Increasing the EOR activity of certain synthetic alkylaryl sulfonates,” DOE/METC/TRP-83-3, November 1982.
While pure alkylaryl sulfonates, such as hexadecyl benzene sulfonate, can generate adequate phase behavior and low interfacial tension with light alkanes, they are unsatisfactory when dealing with heavier crude oils, particularly those with a high wax content. They do not form normal phase behavior when mixed with crude oil and brine of varying salinity. At low salinity, surfactant predominantly stays in the aqueous phase, forming a lower-phase microemulsion; at high salinity the surfactant predominantly stays in the oil phase, forming an upper-phase microemulsion. As noted in
Improved Oil recovery by Surfactant and Polymer Flooding
, Academic Press, 1977, normally, a surfactant-oil-brine system that has high oil recovery potential exhibits a lower- to middle- to upper-phase microemulsion transition as salinity increases. Near the mid-range salinity, often termed optimal salinity, a middle-phase microemulsion forms with appreciable amount of oil and brine solubilized in the microemulsion phase. However, if the oil contains a significant fraction of wax, the above phase transition often does not occur and the solubilization capacity is low, resulting in high interfacial tension and poor oil recovery capability.
Additionally and especially with low oil prices, the surfactant must be cost effective. Prior methods which use narrow selections of carbon chain lengths increase the cost because of the large quantities of unsuitable byproducts and/or the need for more tightly controlled reactor conditions or specialized catalysts.
Thus highly desirable would be to have a recovery process and composition useful in waxy crudes. Also desirable would be to have a composition which usefully includes a broad spectrum of carbon chain lengths so substantially complete production runs can be used.
SUMMARY OF THE INVENTION
The present invention relates to recovering oil from a subterranean formation by surfactant flooding and addresses the previously recited desirable features and also provides other benefits obvious to the ordinary skilled artisan. The process is especially useful when the reservoir oil has high wax contents, e.g., greater than 20 volume percentage wax, wherein the wax is a parafine with 20 or higher carbon number. A method of recovering crude oil from a subterranean formation which comprises: (a) injecting into said formation an aqueous solution containing an effective amount of alkylaryl sulfonate surfactant, said sulfonate prepared by alkylating aromatic compounds with an alpha-olefin stream having a broad distribution in olefin carbon numbers, sulfonating and then neutralizing the resulting alkylate, and (b) displacing said solution through the formation to recover hydrocarbons from a production well. The invention also relates to an alkylaryl sulfonate composition wherein the alkyl has a broad range of carbon chain lengths greater than 10, preferably 12 to 58. More preferably 12 to 40 or also more preferably 12 to 32 and an aryl of benzene, ethylbenzene, toluene, or xylene wherein a major proportion is preferably a xylene.
REFERENCES:
patent: 3601198 (1971-08-01), Ahearn et al.
patent: 3858656 (1975-01-01), Flournoy et al.
patent: 3933201 (1976-01-01), Kerfoot et al.
patent: 3939911 (1976-02-01), Maddox et al.
patent: 4194565 (1980-03-01), Kalfoglou
patent: 4287902 (1981-09-01), McClaflin et al.
patent: 4452708 (1984-06-01), Aldrich et al.
patent: 4608204 (1986-08-01), Lew et al.
patent: 4699214 (1987-10-01), Angstadt
patent: 4743385 (1988-05-01), Angstadt et al.
patent: 4891155 (1990-01-01), Fernley et al.
patent: 4932473 (1990-06-01), Borchardt
patent: 6022834 (2000-02-01), Hsu et al.
patent: 6043391 (2000-03-01), Berger et al.
patent: 0 177 098 (1989-12-01), None
patent: 2 557 198 (1984-12-01), None
patent: 1 087 337 (1967-10-01), None
patent: 2 165 280 (1986-04-01), None
patent: 99/05241 (1999-02-01), None
Malmberg, E. “Large Scale Samples of Sulfonates for Laboratory Studies in Tertiary Oil Recovery: Preparation and Related Studies, Final Report” USDOE Report No. FE-2605-20, Jan. 1979.
Malmberg, Earl W. et al., “Characterization and Oil Recovery Observations on a Series of Synthetic Petroleum Sulfonates,” SPEJ (Apr. 1982) pp. 226-236.
Comberiati, J.R., et al., “Increasing the EOR Activity of Certain Synthetic Alkylaryl Sulfonates,” GUS DOE/DOE-METC/TRP-83-3, Nov. 1982.
Shah, D.O. et al., “Improved Oil Recovery by Surfactant and Polymer Flooding” (Academic Press, 1977) pp. 383-437.
Campbell Curtis B.
Chou Shang
Chevron U.S.A. Inc
Suchfield George
Zavell A. Stephen
LandOfFree
Oil recovery method for waxy crude oil using alkylaryl... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Oil recovery method for waxy crude oil using alkylaryl..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Oil recovery method for waxy crude oil using alkylaryl... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2439297