IMPROVEMENT OF CARBON DIOXIDE SWEEP EFFICIENCY USING IN SITU MICROBES TO MODIFY RESERVOIR PERMEABILITY

This project links carbon dioxide water-after-gas (WAG) flood with microbial permeability profile modification (MPPM). This new technology utilizes nitrogen and phosphorous compounds to stimulate the growth of the indigenous microflora in the most permeable zones of the reservoir, thereby forcing water or carbon dioxide to less permeable zones of the reservoir and increasing sweep efficiency. Demonstration of MPPM with waterflood alone extended the life of the test field over six years and resulted in the recovery of 600,000 additional barrels of oil for an increased cost of only $1.32 per barrel.

Nutrient solutions will be designed to promote growth of the indigenous microflora of the Eutaw Formation, a reservoir sandstone of southeastern Mississippi. In the laboratory, these nutrient solutions will then be injected into core samples to quantify the effect of microbe growth on flow of fluids. Concurrently, petrography, X-ray diffraction, confocal microscopy, and high-resolution CT imagery will be used to determine the mineralogy, distribution of microbes, and pore structure of the reservoir. In the demonstration phase nitrogen and phosphorous compounds will be added to the injection water of the WAG flooding procedure. The field will be monitored to validate the improvement of the carbon dioxide flood caused by MPPM.