Process for enhanced oil recovery employing petroleum sulfonates

Claim 1

A process for enhanced oil recovery comprising, in combination, the steps of: (A) injecting at least one input well located in a petroleum-containing formation with an amount equal to about 1 to 50% pore volume of said formation of a micellar system comprised of a hydrocarbon, water and at least one petroleum sulfonate comprising on a 100 organic weight percent total weight basis: (1) from about 5 to 98 weight percent of monosulfonated hydrocarbon, (2) from about 0 to 50 weight percent of polysulfonated hydrocarbon, and (3) from about 2 to 90 weight percent of non-sulfonated petroleum, said composition having been prepared by: (I) intimately contacting a flowable liquid mixture with from about 5 to 40 parts by weight of a sulfur trioxide for each 100 parts by weight of said flowable liquid mixture at a temperature of about 77° to 392° F., said contacting being continued for a time at least sufficient to sulfonate at least about 10 weight percent of total sulfonatable components present in said flowable liquid mixture so as to attain a crude acidic sulfonation reaction mixture, and (II) intimately contacting said crude acidic reaction mixture with about 0.5% to 20% by weight, on a 100 weight percent total reaction mixture basis, of water and maintaining the so-attained mixture at a temperature of about 50° to 150° C. for period of time ranging from about one minute to about 60 minutes; and (III) nuetralizing the resultant crude acidic reaction mixture-water mixture with a sufficient amount of a base to attain a pH within the resultant mixture in the range of about 3 to 12; said flowable liquid mixture comprising on a 100 weight percent total mixture basis: (a) from about 85 to 99.5 weight percent of a petroleum oil feed stock, and (b) from about 0.5 to 15 weight percent of an additive, said petroleum oil feed stock being characterized by (a 1 ) having an API gravity ranging from about 5° to 60° at 60° F., (a 2 ) having a boiling point (corrected atmospheric) ranging from about -20° to 1400° F., and (a 3 ) containing from about 10 to 95 weight percent (100 weight percent total stock basis) of sulfonatable components, said additive being characterized by (b 1 ) being comprised of unsulfonatable organic radical portions possessing an average molecular weight range from about 55 to 6000, (b 2 ) having a boiling point in the range from about 212° to 932° F. corrected atmospheric, and (b 3 ) a preponderance of such radicals each having attached at least one proton replaceable by a sulfo group and at least one moiety selected from the group consisting of an aromatic nucleus, an olefinic carbon pair, and an oxygen atom directly bonded to a carbon atom by at least one bond, and (B) displacing said micellar system through said petroleum-containing formation so as to displace petroleum therefrom.