Fossil fluids are generally recovered from underground formations by penetrating the formation with one or more wells and pumping or permitting the fossil fluid to flow to the surface through the well. In primary recovery, a natural driving energy such as an underlying active water drive or a gas under some minimum pressure may possess sufficient pressure to drive the fluid to the well and then the surface. In many instances, the natural driving energy is insufficient or becomes insufficient to cause the fluid to flow to the well. Thus, a substantial portion of the fossil fluid to be recovered can remain in the formation after depletion of the natural driving energy. In such cases, various secondary or tertiary recovery techniques must be applied to recover the remaining fluid.
One such technique involves the injection of water through one or more injection wells to drive the residual fluid towards a producing well. When the injection of water no longer results in acceptable rates of production, the producing well must either be abandoned or subjected to other processes to further increase extraction. A variety of processes are known including steam flooding, polymer flooding, alkali flooding, miscible flooding with carbon dioxide, and flooding with aqueous surfactant solutions. With respect to flooding with an aqueous surfactant solution, a surfactant package is added to the injection water and injected into the well for the purpose of decreasing the interfacial tension between the injection water and fossil fluid phases thus leading to an increase in fossil fluid extraction. The challenge one skilled in the art faces when implementing such a process is determining an effective combination of components which make up the surfactant package. Many combinations must generally be tried before a suitable surfactant package can be formulated having good tolerance towards the multivalent cations found in the brine of many formations as well as having low adsorption onto rock of the formation. For example:
U.S. Pat. No. 3,811,504 discloses the use of a three surfactant system containing an alkyl sulfate, an alkyl polyethoxylated sulfate, and a polyethoxylated alkylphenol;
U.S. Pat. No. 3,890,239 discloses a surfactant composition useful in recovering oil from a formation that includes an organic sulfonate, a sulfated or sulfonated oxyalkylated alcohol and a polyalkylene glycol alcohol ether;
U.S. Pat. No. 4,463,806 discloses a surfactant package containing a water-soluble ether-linked sulfonate, an alcohol and a petroleum sulfonate or alkylbenzene sulfonate;
U.S. Pat. No. 7,629,299 discloses the use of alcohol ether sulfonates derived from unsaturated alcohol ethers;
U.S. Pat. Publ. No. 2005/01999395 discloses the use of an alkali and an alkylaryl sulfonate surfactant derived from alpha-olefins for recovering oil from a formation;
U.S. Pat. Publ. No. 2006/0185845 discloses a composition that includes an aliphatic anionic surfactant and an aliphatic nonionic additive for use in treating a formation;
U.S. Pat. Publ. No. 2007/0191633 discloses a blend or recovering oils that contains water or brine, an alcohol or alcohol ether and a bifunctional anionic surfactant;
U.S. Pat. Publ. No. 2009/0270281 discloses a surfactant mixture including a hydrocarbon radical having 12-30 carbons and a branched hydrocarbon having 6 to 11 carbon atoms for use in tertiary oil extraction;
U.S. Pat. Publ. No. 2011/0046024 discloses the use of an alkylated hydroxyaromatic sulfonate, a solvent, a passivator and a polymer for recovering oil from a formation;
U.S. Pat. Publ. No. 2011/0048721 discloses the use of high molecular weight sulfated internal olelfin sulfonate sulfates and high molecular weight dialkylphenol alkoxylate sulfonate sulfates for use in oil recovery; and
U.S. Pat. Publ. No. 2011/0190174 discloses tristyrylphenol alkoxylate sulfates and their use as a surfactant in oil recovery applications.
Because of the numerous surfactants available for use, there is a need in the art for cost effective methods for determining new surfactant packages useful in the recovery of fossil fluids, especially under high salinity and high temperature conditions. Provided herein are methods and surfactant formulations addressing the needs in the art.