A Successful application of microbial EOR field test in Fuyu oilfield, China.

Abstract

Microbial EQR (MEOR) field test was carried out in Fuyu oilfield, China during 1996-2001. In Fuyu oilfield, patterned waterflooding has been applied for over 20 years and the current averaged water cut in test area has reached at approximately 90% due to the existence of high permeable layer.In this field test, a microbe named CJF-002 was applied. CJF-002 has a feature of producing insoluble polymer by feeding molasses as a nutrient.This MEOR test has focused on profile modification process by produced insoluble polymer in the reservoir to reduce water channeling. Prior to the field test, a tracer test was carried out to measure the baseline of reservoir characteristics.CJF-002 and molasses were injected from two water injectors.Increases of oil production and reduction of water cut were observed soon after CJF-002 and molasses injection started.After two-month microbial treatment, total oil rate in the test area increased approximately three times larger than before. The chemical and biological monitoring during the field test proved that CJF-002 survived and produced some amount of insoluble polymer in the reservoir.Result of tracer tests also indicated that microbial injection could improve the sweep pattern of injection water. Moreover, according to the simulation study of MEOR field test, the production performance of MEOR field test has successfully simulated by assuming the insoluble polymer had reduced the permeability of high permeable zone to 1/10 of its original value.This paper presents the successful results of MEOR field test and discussion on the effects of microbial profile modification process.