Influence Of Reservoir Parameters On Bacterial Enhanced Oil Recovery

Abstract

The aim of this paper is to show the scope of the applicability of bacteria for enhanced oil recovery (EOR) in the oil reservoirs. The Application of conventional EOR-techniques is economically problematic because of the high production costs and oil prices fluctuation. For this reasons other tertiary methods have to be developed to minimize the economic risk of oil recovery. One solution to this problem is the Microbially Improved Oil Recovery (MIOR). With this method, oil mobilization is due to the injection of bacteria into an oil-bearing reservoir. In this paper, the methods to find suitable bacteria, the assessment of their oil mobilizing abilities and the determination of the responsible mechanisms for oil mobilization will be also discussed. Static Autoclave experiments (without reservoir rock) and dynamic flooding tests have been carried out. With the help of the static experiments under reservoir conditions (pressure, temperature and salinity), two oil mobilizing bacterial strains have been found. Flooding experiments were carried out under reservoir conditions, in order to verify the ability of applied bacteria to mobilize residual oil in place and to detect the oil mobilizing mechanisms. It was found, that the most important factors influencing the oil mobilization are: the permeability reduction factor of the reservoir pores and the change in wettability due to the growth of bacteria.