Study Of Microbial Enhanced Oil Recovery In Yanchang Oilfield

As China’s major oil fields going into the later exploitation stage, the development ofYanchang oilfield in the Erdos basin gradually was getting more attention. But because ofits low permeability, heterogeneity of formation characteristics, the oil recovery rate alwayshad been lower than the other oilfield. The microbial enhanced oil recovery technology asthe three oil recovery technology after the one or two oil production, became an effectivemethod to solve this problem. The reservoir conditions of Yanchang oilfield was suitablefor the application of microbial enhanced oil recovery technology, but the research andapplication in this area compared with other oilfield was not far enough. The main purpose ofthis paper was, combined with the characteristics of Yanchang oilfield, screened somestrains which can be applied to the production of microbial enhanced oil recovery, identifythe characteristics of the bacteria, and microbial enhanced oil recovery technology related,evaluate the strain on the potential application in microbial enhanced oil recovery. In thispaper, according to the test results, following conclusions are achieved:There was a dehydrogenase activity measurement method. The crude enzymepreparation and deionized water mixed at the mass ratio of1:40in the triangle bottle. Theactivation process was to shake with oscillation rate120r/min at28℃for15h. Then rapidfilter paper was used to separate mixture. Enzyme solution and TTC-glucose reacted inthermostatic water bath at40℃. As the reaction mixture became reddish, removed after90min and plused CH3COOC2H5with the full shake. Then put in4℃refrigerator for5~6h.The clarify organic layer was assayed by colorimetry at wavelength485nm. Finallydehydrogenase activity was calculated according to the standard curve.3bacteria strains isolated from crude oil or oil contaminated soil can obviously changethe phy-chemical properties of oil. Combined with the morphological observation,physiological and biochemical characteristics and16S rDNA sequence analysis, theywere identified to be Dietzia cerrcidiphylli(X10), Micrococcus yunnanensis (X19) and Pseudomonas aeruginosa(X22).Research shows that,3strains of bacteria with high potential for MEOR. Because ofthe metabolism of surfactant, P. aeruginosa can significantly change emulsification andadhesion of crude oil, which has the strong practical potential for MEOR; Degradation abilityof Mic.yunnanensis is stronger than others,especially for gums and asphalt, so this strain willhave greater application value of heavy oil recovery and oil degradation rate of pollutants.Apparent concentration of surfactant in fermentation liquid and its determinationmethod are presented. Surfactant SDS concentration and oil spreading diameter relationship isthat y=0.0002x2+0.0325x-0.0506. Deremine the oil spreading diameter of fermentationliquid, we can use the mathematical model to calculate the total amount of surfactantequivalent to SDS concentration. The SDS concentration can be called apparentconcentration. This method is simple, practical.After the fermentation medium of P. aeruginosa was optimized, the fermentationmedium is low cost and high performance.Glycolipid surfactant could be produced by P. aeruginosa. P. aeruginosafermentation fluid has good effect of EOR in the indoor simulation experiment, whichcleaning efficiency was higher than water, and cleaning efficiency in low permeabilityor heterogeneous simulation oil layer was higher than high permeability and is suitablefor low permeability, heterogeneous oil layer of Yanchang oilfield, with the higheractual application value in MEOR.