Using Bacteria to Improve Oil Recovery from Arabian Fields

Abstract

Large quantities of residual oil remain in Arab oil reservoirs after the primary recovery and waterflooding stages. Because of the large area of the Saudi oil fields, the amount of residual oil is enormous. According to the latest publications, the original oil in place in Saudi Arabia is about 700 billion barrels. Only around 250 billion barrels, 35% of the total oil in place, can be produced by conventional methods. More than 90 billion barrels, as much as twice the proven reserve of the United States and Canada combined, could be added to Saudi Arabia's proven reserve if only 20% out of the 450 billion barrels left in place was produced through methods for enhanced oil recovery. Any method that can recover a significant part of this residual oil would be of great importance and should be investigated. Microbial Enhanced Oil Recovery (MEOR) has been recognized as a potentially cost-effective method of recovery. This paper investigates the applicability of MEOR for recovering more of the oil under the Arab oil fields. Based on the analysis of data from more than 300 formations in seven Arab countries (Saudi Arabia, Egypt, Kuwait, Qatar, United Arab Emirates, Iraq, and Syria), we studied the possibility of applying MEOR to the Arabian area. The basic parameters studied include the permeability of the formation, reservoir pressure and temperature, crude oil viscosity and API gravity, and connate-water saturation in the formation and its salinity. We found that the Saudi, Iraqi, and Egyptian oil fields are very good candidates for MEOR processes; Qatar, Kuwait, and Syria have some potential for MEOR. However, because of the conditions of its reservoirs, the oil fields of the United Arab Emirates have no potential for MEOR. MEOR is expected to recover up to 30% of the residual oil under present conditions in the Arab reservoirs. However, the actual recovery can only be determined through laboratory and pilot tests under field conditions. A new technology should be developed so that MEOR can be applied successfully.