Improved Oil Recovery from Combining Well Stimulation with Novel Surfactant Technologies

Abstract

Abstract Oil and natural gas will continue to be the primary sources of energy for the foreseeable future. However, with respect to oil, field recovery rates are low (35 percent or less) and access to proven reserves is diminishing. New and better chemical technologies to maximize oil recovery are called for – especially for enhancing response from conventional well treatments in mature fields. Enhancing oil recovery rate even fractionally can pay enormous dividends. Sandrea and Sandrea1, reported that a one percent increase in global recovery efficiency could yield an additional 88 billion barrels of oil – a volume sufficient to replace about three years of current worldwide production. Thus, very modest improvements in well performance on a global basis could substantially elevate production and unlock vast amounts of oil reserves from reservoirs already in exploitation. Beneficial consequences would be reduced dependence on new drilling and reliance on new discoveries. Clearly, within this context, technologies that can be readily and economically applied to improve oil recovery from existing wells are very attractive. This paper introduces a novel concept in which certain surfactants with enhanced oil recovery (EOR) properties can be combined with traditional stimulation fluids; that is, production well treatments are used to deliver EOR surfactant chemistry to the formation. This concept would enable extraction of additional oil through a spontaneous imbibition process. Combined stimulation / EOR applications include propped fracturing, acid fracturing, matrix stimulation, and scale inhibitor squeeze treatments. The paper presents laboratory data demonstrating the efficacy of two new surfactant chemistries designed to enhance both stimulation and oil recovery in naturally fractured carbonate and diatomite reservoirs. Specifically, data will be provided to show the highly synergistic effect of combining a particular EOR surfactant with carbonate acidizing. Finally the paper discusses the applications and deployment of this EOR surfactant-aided, production enhancement concept.