Oil recovery method using alkali and alkylaryl sulfonate surfactants derived from broad distribution alpha-olefins

Abstract

An oil recovery process is disclosed which uses an alkali(s) and a particular class of alkylaryl sulfonate surfactants. The surfactants are derived from an alpha-olefin stream having a broad distribution of even carbon numbers ranging from 12 to 28 or more. The olefin stream is reacted with aromatic feedstock, such as benzene, toluene, xylene, ethylbenzene, or a mixture thereof to form alkylates, and then reacted with SO3 to form sulfonic acids. Alternatively, the surfactant can be formed by first reacting an alpha-olefin stream having a broad distribution of carbon numbers ranging from 12 to 28 or more with SO3 to form the olefin sulfonic acid that is subsequently used to alkylate an aromatic feedstock. The use of alkali(s) and broad distribution alpha-olefins sulfonate based surfactant has the improvements of requiring ultra-low surfactant concentrations and providing ultra-low interfacial tensions over a wide range of alkali concentrations with crude oils, especially waxy crude oil, having a broad distribution of carbon numbers.

Description

FIELD OF INVENTION [0001] The present invention is directed to enhanced oil recovery (EOR). More specifically, the present invention is directed to enhanced oil recovery of crude oil using a mixture of alkali(s) and alkylaryl sulfonate surfactant derived from broad distribution alpha-olefins. BACKGROUND OF THE INVENTION [0002] This invention is an improvement over U.S. Pat. No. 6,269,881 and much of the background material is drawn from this reference and all references included in U.S. Pat. No. 6,269,881 are included herein. [0003] Alkylaryl sulfonates with narrow distribution carbon chains have long been recognized as promising surfactants for EOR. They can be manufactured in fairly large quantities and can generate adequate phase behavior and low interfacial tensions (IFT) with oils under favorable conditions. However, pure alkylaryl sulfonates such as hexadecyl benzene sulfonate or those having a narrow distribution carbon chains, cannot generate adequate phase behavior and low ...

AI Technical Summary

Benefits of technology

[0007] The present invention also includes an alkali(s) and alkylaryl sulfonate surfactant composition for enhanced oil recovery giving the improvements of requiring ultra-low surfactant concentration and providing ultra-low interfacial tensions over a wide range of alkali(s) concentrations. Said composition comprises one or more alkali(s) along with an alkylaryl sulfonate wherein the alkyl chain includes C12 to C30+ carbon chain lengths and wherein the carbon chain is straight, branched or mixtures thereof, and wherein the aryl group is selected from the group benzene, toluene, xylene, ethyl benzene, or mixtures thereof. The alkali(s) that may be used include any inorganic or organic salt, or the mixture thereof, that is capable of increasing the pH of the injection solution above 9.

Problems solved by technology

However, pure alkylaryl sulfonates such as hexadecyl benzene sulfonate or those having a narrow distribution carbon chains, cannot generate adequate phase behavior and low interfacial tension with a wide range of crude oils especially when dealing with heavier crude oils, particularly those with a high wax content.

Furthermore, when used together with alkali in alkali surfactant flood, alkylaryl sulfonates with narrow distribution carbon chains are only effective over limited ranges of alkali which is detrimental to efficient oil recovery.

Prior methods, which use alkylaryl sulfonates with narrow distribution of carbon chain lengths, increase the cost because of the large quantities of unsuitable byproducts and / or the need for more tightly controlled reaction conditions or specialized catalysts required to manufacture such surfactants.

The higher concentration of the surfactant and the optima salinity required are uneconomical and unsatisfactory for a large quantity surfactant flood.

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