Observation of Oil-Bank Formation During Micellar Flooding

Abstract

This paper was prepared for the Improved Oil Recovery Symposium of the Society of Petroleum Engineers of AIME, to be held in Tulsa, Okla., March 22–24, 1976. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgement of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Observation of micellar systems within porous media is important to determine the fate of porous media is important to determine the fate of each component (surfactant, cosurfactant, aqueous phase, and hydrocarbon) during the displacement phase, and hydrocarbon) during the displacement of tertiary oil. It is possible to obtain such information with the pulsed nuclear magnetic resonance spectrometer and appropriate experimental design. Various micellar systems were observed displacing tertiary decane and water from small sandstone and porcelain cores. From an analysis of spin-lattice relaxation curves it was found that micellar system water and cosurfactant are influenced by pore surfaces when an oil-external microemulsion is introduced into a sandstone or porcelain core. This result implies that interaction of the micellar system with the porous material may be more important than the nature (oil or water) of the external phase for efficient tertiary oil displacement. phase for efficient tertiary oil displacement. High (water-external microemulsion) and low (oil-external microemulsion) water content micellar systems were observed during displacement of decane from both types of porous material. It was noted that the high water content system banked oil (based on a comparison to a piston-like displacement model) better than the low water content system. Also, it was found that behavior (oil-bank formation) of both types of micellar systems was superior in the sandstone core suggesting that the porous material has an important influence on tertiary recovery. Reduction of reservoir water-pore surface interaction for a fraction of the in-place water was suggested by the results obtained with the high water content micellar system. Other results show the effect of CaCl2 and cosurfactant concentration on the formation of an oil-bank during displacement. For a particular micellar system composition high concentrations of CaCl2 in reservoir brines need not be detrimental for initial mobilization of tertiary oil. Introduction Examination of micellar solutions in porous materials is important to determine the fate of each component during the displacement of tertiary oil. Also, different kinds of reservoir rock may alter the displacement efficiency of these types of fluids. It is possible to trace certain components of micellar solution within core material by appropriate experimental design and use of the pulsed nuclear magnetic resonance (NMR) technique. This technique has been used to investigate fluids associated with a variety of different porous solids. Relating the response of water confined in porous media to permeability and/or pore size distribution has been the subject of recent papers.