The Physical System

Abstract

Long before the oil price shocks of the past decade engineers recognized a need for improved methods of exploiting petroleum resources. Conventional production practices including waterflooding are so inefficient that, of all the oil discovered in the United States as of 1980, less than 35 percent is identified as either having been recovered or remaining as proved reserves (Doscher, 1980). By this count, about two thirds of the nation’s known original petroleum resources cannot be produced using standard primary and secondary methods. Miscible gas flooding, especially with CO₂ as the injected fluid, is one of the more promising technologies for enhancing oil recovery and thus for shrinking the gap between discovered resources and crude reserves (Holm, 1982). Engineers designing miscible gas floods rely on mathematical models to compare possible operating strategies and to estimate the amount and timing of additional production. We shall examine new techniques applicable to the numerical simulation of miscible gas floods and similar compositional flows in porous media.