Title: Water-in-oil microemulsion drilling fluids

Abstract: An oil-external microemulsion drilling fluid having a wide range of tolerance for salinity, having good gel strength and low fluid loss characteristics, and also obtained by mixing about 1% to about 30% of a sodium petroleum sulfonate having an average equivalent weight within the range of about 350 to about 525, about 5% to about 84% of a hydrocarbon (e.g. diesel fuel), about 15% to about 90% of an aqueous medium (can contain water soluble salts), about 0.01 to about 20% of a cosurfactant (e.g. alcohols such as primary amyl alcohol) and about 0.1 to about 15% of bentonite clay. Weighting agents, e.g. barite, and other desired additives can be added to the microemulsion.

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Inventors: Hayes, John B. (Littleton, CO, US)
Haws, Gerald W. (Littleton, CO, US)
Gogarty, William B. (Littleton, CO, US)

Application Number: 615280
Filing Date: 1975-09-22
Publication_date: 1977-03-15
Assignee: Marathon Oil Company (Findlay, OH)
Primary Class(es): 507/135 175/65, 507/139, 516/22, 516/25, 516/65
Other Classes:
US Patent Ref:

2696468	Dec, 1954	Fischer	252/8.
2739120	Mar, 1956	Fischer	252/8.
3002923	Oct, 1961	Barker et al.	252/8.
3111491	Nov, 1963	Atkins	252/8.
3252903	May, 1966	Crittendon	252/8.
3254714	Jun, 1966	Gogarty et al.	166/275.
3330343	Jul, 1967	Tosch et al.	166/275.
3734856	May, 1973	Son	252/8.

Other Refs:
Primary Examiner: Guynn, Herbert B.
Assistant Examiner:
Attorney: Herring; Joseph C., Hummel; Jack L.