Studies on sulphonates for enhanced oil recovery

The hydrocarbon/surfactant solution IFT characteristics for several commercial and synthesized sulphonates were studied with various alkanes and the crude oils. It was found that only sulphonates of specific structures and their combination in specific proportions produced ultra low interfacial tension (ULIFT) (< 10(-2) dynes/cm) with specific hydrocarbons and crude oils. The mixtures of sulphonates of specific structures in specific proportion, which produced ultra low tension with one or more crude oil also, gave higher tertiary recovery under laboratory conditions as compared to commercial sulphonates. The solubilization of hydrocarbons by sulphonates studied also show that very high solubilization (20 moles/g) of sulphonates is highly specific and depends upon the structure of sulphonates and their specific combinations in specific proportions. None of the commercial sulphonates solubilized crude oil in large quantities and only a few combinations of sulphonate solutions solubilized large quantities of different crude oils. These sulphonates produced much higher oil recovery of Ankleswar crude under laboratory conditions in low-tension floods. It is recommended that pilot studies be taken for synthesis of these sulphonates in large quantities for undertaking field trials to study the tertiary oil recovery from Indian oil fields and the economics of recovery and conditions of substantial recovery of crude oil established in view of high crude oil prices prevalent from time to time.