Standard Oil Company (indiana)

The Standard Oil Company

Betty J Felber

Dwight L Dauben

Dan D Lawrence

Charles A Christopher

Richard E Marrs

Highly conductive zones of subterranean formations are treated with aqueous fluids containing gel-forming amounts of water-soluble basic lignins. Suitable treating fluids contain about 2 to about 8 wt. % sodium hydroxide solution. The lignin solutions gel within the formation due to reactivity with oil-water and/or the rock matrix. Alternately, following the injection of the gel-forming fluids, acidic gas is injected to cause gel formation.

Method for sweep improvement utilizing gel-forming lignins

Highly conductive subterranean zones are treated with aqueous fluids containing gel-forming amounts of water-soluble lignosulfonate and silicate. Suitable treating fluids contain about 2 to about 5 weight percent sodium or ammonium lignosulfonate and sodium silicate at a weight ratio of SiO.sub.2 to lignosulfonate of about 0.2 to about 1.

Silicate activated lignosulfonate gel treatments of conductive zones

Highly conductive zones in subterranean formations are treated with aqueous fluids containing gel-forming amounts of water-soluble lignosulfonate and silicate. Suitable treating fluids contain about 2 to about 5 weight percent sodium or ammonium lignosulfonate and sodium silicate at a weight ratio of SiO.sub.2 to lignosulfonate of about 0.2 to about 1.

Formation treatment with silicate activated lignosulfonate gel

An improved method for mobility control application in viscous oil reservoirs including (a) heating a lignosulfonate solution, prior to injection into an oil bearing formation, for a period of time sufficient to produce a more viscous lignosulfonate solution (e.g., 8% sodium lignosulfonate held at 375.degree. F. for 50 hours yielding a 86 cp fluid @ 84 sec.sup.-1 measured at room temperature), (b) cooling the resulting heat treated lignosulfonate fluid to a reservoir condition and (c) injecting this fluid into the formation. Fluids produced in this manner are useful as mobility buffers during a waterflood or a micellar flood process.

Method of using polymerized lignosulfonates for mobility control

A method of selective plugging of undesirable high permeability streaks and channels in oil-bearing reservoirs during high temperature (250.degree. F or higher) injection recovery processes such as steamflooding, underground combustion, flooding of a naturally occurring high-temperature reservoir or the like. Improved sweep efficiency can be effected by injecting a gel-forming solution consisting essentially of sodium or ammonium lignosulfonate and water or brine in the absence of other gelation promoters and then allowing the high temperatures of the underground formation to promote gelation. Optionally, a precooling water injection step can be used prior to placement of the gel-forming solution. This system has the advantage of gel times which are sufficiently long at temperatures in excess of 250.degree. F to permit placement of large volumes characteristic of commercial use. This method is particularly useful in selectively forming firm, strong gels in thief zones for steamflooding recovery operations.

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Tulsa, OK, United States of America

Betty J Felber