MICROBIAL ENHANCED OIL RECOVERY (MEOR)
Microbial consortia activity within an oil and gas reservoir is a potentially powerful biological system that can profoundly affect the entire reservoir. Certain species of microorganisms can be manipulated and controlled to release trapped oil in significant and economic quantities. Some microbial methods aid inn paraffin removal while others are designed to modify heavy oil. Still other micro-organisms produce chemicals, such as surfactants, polymers, or solvents that are useful in oil recovery processes, either in above ground facilities or in situ. Most of the methods are designed to treat single wells and not the entire fields. Several factors make microorganisms attractive for improved oil recovery. They are self-replicating and relatively inexpensive to produce. The nutrients required to sustain their growth are economically priced. Microorganisms produce many of the chemicals, such as gases, surfactants, acids, solvents and polymers involved in improving oil recovery. The general criteria for microbes to exist in the reservoir environment are: 1. Salinity should be less than 15% NaCl. 2. Temperature less than 1800F. 3. Depth less than 8000 ft. 4. Trace elements (As, Se, Ni, Hg) less than 10-15 ppm 5. Permeability greater than 50 md. 6. Oil gravity greater than 150 API. 7. Residual oil saturation greater than 25%. Microbial Enhanced Oil Recovery (MEOR) has several unique advantages that make it an economically attractive method to enhance oil recovery. MEOR processes do not consume large amounts of energy as do thermal processes and MEOR processes do not depend on the price of crude oil as do many chemical recovery processes. Because microbial growth occurs at exponential rates, it should be possible to produce large amounts of useful products quickly from inexpensive and renewable resource. Continued industrialization and economic growth will increase the demand for oil. The demand for crude oil often exceeds existing production in many countries. Conventional oil production technologies are able to recover only about one-third of the oil in the reservoir. Microbially enhanced oil recovery may offer an economic alternate oil recovery may after an economic alternate to enhance oil recovery. This seminars gives a brief idea on what is microbially enhanced oil recovery and the various processes involved.