Abstract: An improved anionic waterflood additive is prepared by partially chlorinating a normal alkane having about 10 to about 18 carbon atoms to about 2 to about 15 weight percent chlorine content, employing the chlorinated alkane to alkylate an aromatic hydrocarbon, such as benzene; sulfonating the thus formed alkylate or a fraction thereof to form a sulfonic acid; converting the sulfonic acid to a sulfonate by reacting with a base component, such as an alkali metal hydroxide, ammonium hydroxide, or an alkali metal carbonate; and overbasing the sulfonate by admixing with an excess of base component such that the ratio: "weight of excess base component/weight of sulfonate" is about 0.03 to about 3.0. The anionic waterflood additive is injected into a petroliferous formation, the formation is waterflooded, and oil is recovered.

Abstract: An improved anionic overbased waterflood additive comprises a base component, a first sulfonate component derived from an alkylation reaction product employing a branched-chain alkene as the alkylating agent, and a second sulfonate component derived from an alkylation reaction product employing a partially chlorinated normal alkane as the alkylating agent, wherein the base component is present in the weight ratio range of 3/100 to 300/100, base component to total sulfonate, and wherein the weight ratio of the first sulfonate component to the second sulfonate component is in the range of 1/9 to 9/1. The overbased waterflood additive may be formed prior to injection into a petroliferous formation or may be formed in situ by first injecting the total sulfonate followed by the base component.

Abstract: An improved anionic waterflood additive is prepared by alkylating an aromatic hydrocarbon such as benzene with a branched-chain alkene having about 10 to about 35 carbon atoms such as a propylene tetramer dimerization reaction product in the presence of an alkylation catalyst such as AlCl.sub.3 ; sulfonating the thus formed alkylate product or a fraction thereof to form a sulfonic acid; converting the sulfonic acid to a sulfonate by reacting with a base component such as an alkali metal hydroxide, ammonium hydroxide, or an alkali metal carbonate; and overbasing the sulfonate by admixing with an excess of base component such that the ratio; "weight of excess base component/weight of sulfonate" is about 0.03 to about 3.0. The anionic waterflood additive is injected into a petroliferous formation, the formation is waterflooded, and oil is recovered.