Micellar Solution Flooding - Field Test Results And Process Improvements

Abstract

Abstract Up-to-date results of large and small micellar solution field tests illustrate the successful application of the process. Advances in techniques for laboratory-scale test design and for the manufacture of injected fluids provide tile basis for economic application of the process. Introduction MICELLAR SOLUTION FLOODING (the Maraflood ™ oil recovery process) is a viable enhanced oil recovery technique. The process may be used either for secondary or tertiary recovery. Although significantly more expensive and risky than waterflooding, the process is economical in a large category of petroleum reservoirs with current crude price projections. This paper briefly describes the micellar flooding process, gives results of three field tests, describes a core flooding technique for process evaluation, presents a new process for direct sulphonation of crude oil and the manufacture of micellar solution in the field, and summarizes process economics. The paper also comments n the future development and application of the process. The micellar solution flooding process involves injecting a sequence of fluids into a producing petroleum reservoir.(1, 2) Initially, a slug of micellar solution (commonly referred to as a micellar slug or simply a slug) is injected. While effective, the micellar slug displaces essentially 100 % of the oil it contacts. As this material is expensive, it is displaced by a more economical fluid, the mobility buffer. The mobility buffer must be capable of efficiently displacing the slug through the reservoir if slug effectiveness is to be maintained. Thus, the buffer mobility should be lower than slug mobility. (Mobility is defined as effective permeability to flowing fluid divided by apparent fluid viscosity.) If the mobility-buffer mobility is too high, it may finger through the slug, resulting in serious inefficiencies in the micellar flooding process. The mobility buffer may be a viscous emulsion or, more commonly, a polymer-water solution. The buffer is generally displaced by water, in spite of unfavourable mobility control at the water-mobility buffer interface. Water is used because of availability and low cost. It is essential that the mobility buffer bank be large enough to prevent the water from fingering through the mobility buffer into the micellar slug before completion of the flooding process. Typical fluid volumes for tertiary recovery are 5 to 10% pore volume micellar slug, approximately 1 pore volume of mobility buffer and approximately 1/2 pore volume of water. Laboratory development and testing and field testing of the micellar flooding process have been under way for many years, although interest has increased since about 1970(1–15) The process has been proven to be technically successful in a wide variety of field tests.(10, 11, 13, 15, 17) Marathon Oil Company started field testing the micellar flooding process with the Dedrick pilot flood in November, 1962. Since that time, Marathon has completed or licensed 12 field tests in Illinois and Pennsylvania. In addition, one test is still in progress in Illinois and four tests are in progress in Pennsylvania. Information about those tests is summarized in Table 1.