ИСТИНА

A.A. Sitnikov, N.A. Eremin, R.R. Ibatullin A mathematical model of microbial enhanced oil recovery (MEOR) method for mixed type of rock International сonference "Problems of complex development and production of hard-accessible oils and natural bitumens (production and refining), Abstracts, October 4-8, 1994, Kazan, Poster Reports, p. 171. PR-69 THE MATHEMATIC MODEL OF THE MICROBIAL ENHANCED OIL RECOVERY (MEOR) METHOD FOR WATERFLOODED FORMATIONS A. Sitnikov1, R. Ibatullin1, N. Eremin2 1 - Tatar Research and Design Oil Institute, Bugulma, Tatarstan, Russia 2 – Gubkin State Academy of Oil and Gas, Moscow, Russia In this investigation we analyzed MEOR method by means of mathematic modeling. In particular, the mechanism of microbial effect on formation is analyzed, various groups of activity products are separated, and their effects on formation hydrodynamic characteristics are defined experimentally. For this purpose, the mathematic model was built for description of the formation bacteria growth during water flooding. The time-dependence for bacteria (biomass), molasses and metabolites concentrations was founded, and the time of microbial effects was defined. On this base the mathematic model of microbial EOR for fractured-matrix reservoirs was obtained. This is a classic model by Rappoport-Leas type for two (water and oil) phases, in the balance equations of which are included the elements, responding to the effects of bacteria activity. As result the equations system is obtained, that can be solved numerically. Besides, in the first approximation only CO2 and biosurfactant generation were taken into account as a result of bacteria activity. When their concentrations became higher, then oil viscosity and interfacial tension on water-oil contact decreased, the wettability angle reduced, and displacement efficiency grew. The technological characteristics for MEOR method were estimated by means of described mathematic model.