Effects Of Microbial Flooding On Reservoir Physical Properties And Fluid Properties

Microbial enhanced oil recovery(EOR)is a technique to increase oil recovery by injecting or activating microorganisms that can survive in a reservoir.As a new technology of enhanced oil recovery,microbial oil recovery results in a practical microbial method by providing the content and view of bacterial oil production.The concept of microbial enhanced oil recovery(EOR)was first proposed by Beckman,and it was not until 1950 s that the concept of oil recovery was actively studied by Zobell et al.After years of research,that the use of the mechanism of MEOR is mainly produced by microbial metabolites: gas,surfactants,biological polymers,organic acid,solvent and microbial cracking heavy hydrocarbon waxes.Microbial enhanced oil recovery(MEOR)technology has advanced,since 1980,from a laboratory-based evaluation of microbial processes,to field applications internationally.MEOR flooding mechanism,has the unique characteristics of the operation process is simple and no damage to the stratum and the environment and can flexibly adjust the environment according to the stratum strain and nutrition advantage,especially for the poor economic wells,has obvious economic effect of lengthening the life.But the biological characteristics of microbial,there are still some problems,therefore,should continue to improve the technology of production practice and theoretical research in the future,and strive to maximize the use of microbial oil production technology in enhanced oil recovery effect.The reservoir is the basic aggregation of the same pressure system in a single trap.It is a multi interface seepage system formed by the liquid phase and solid rock.Reservoir conditions and fluid properties are the key factors affecting the microbial flooding technology implementation effect,so according to the reservoir conditions and fluid properties affect the metabolism of microorganisms on the reservoir rock interface and the reservoir fluid properties.First,through the indoor microbial screening and evaluation,selecting suitable strain,followed by determination of contact angle change of core sample wetting angle measuring instrument with different concentration of bacteria,affect the effect of microbial metabolism on the surface properties of the rock,and finally through the microbial degradation of crude oil and microbial acidgas etc.effect,influence Study on metabolism of microorganism on fluid properties.The experimental results show that the microbial metabolism can make the core sample surface contact angle decreases,the wetting angle is less than 40.1o,the wettability from hydrophobic to hydrophilic inversion;and the viscosity reducing effect of microorganisms on crude oil is not only metabolites on the chemical action of crude oil is simple,as well as the bacteria involved in the complex biochemical process at the same time;microbial metabolism significantly increased the content of volatile fatty acids in the fluid,the fluid is up to 2816mg/L,pH value decreased to 4.3.The results reveal the biochemical mechanism of microbial oil recovery,which has important theoretical and practical value in promoting the development of microbial oil recovery technology.