Development and Evaluation of Micellar Solutions To Improve Water Injectivity

Versatile micellar compositions have been developed for use in improving the injectivity of water-injection wells. These fluids improve injectivity by removing both residual oil saturation and clogging deposits from the vicinity of the well. The micellar solutions are composed of a hydrocarbon solvent, fresh water with added salt, a petroleum sulfonate surfactant, and a co-surfactant alcohol. Extensive compositional studies were made varying both the type and amount of these components to develop a single water-free micellar concentrate for mixing with water under a diversity of field conditions. A key factor in the development of this practical concentrate is the use of selected ethoxylated alcohols as the co-surfactant. Micellar fluids prepared from this concentrate have shown miscibility with oil and water, stability over a temperature range of 32$ to 200$F, and stability over a broad range of salt contents of the makeup water. In the past, low permeability formations (<20 md) such as limestones and dolomites have not been responsive to treatments with micellar fluids. A staged injection process has been developed to permit treatment in such formations.