Application Of MEOR In Daqing Placanticline For Reservoirs Of Oil-water Transition Zone

In this paper,completed the cultivation of authigenous bacteria, sulfate-reducing bacteria, petroleum hydrocarbon degrading bacteria, hydrocarbon degrading bacteria, zymophyte bacteria,methanococcales bacteria and denitrifying bacteria were 6 types of authigenous bacteria from the Gaotaizi train of Daqing oil。Carried out microbial activation experiments,experiment indicated that authigenous bacteria could enhance recovery ,Hydrocarbon-oxidizing bacteria (HOB) was the best emulsification of crude oil,the viscosity decreased,and produced surfactant.In this paper carried out authigenous bacteria Laboratory Physical Simulation Experiment research in Daqing placanticline for Gaotaizi reservoirs of oil-water transition zone, between natural and artificial core, complex Simulation core flooding experiments carried out various scientific experiments, from the bacterial culture,strain temperature, strain emulsion viscosity, comparing with Tsinghua University on microbial screening ,selection,and the effect of Enhancing Oil Recovery Rate,the experimentthe concluded:(1)From the situation of the authigenous bacteria in natural and the cultured bactera in man-made isotropic rock core, MEOR can improve the recovery of low permeability reservoir.(2)The flooding effects ofâ… bactera and Tsinghua University bactera were better thanâ…¡bactera and authigenous bacteria .(3)authigenous bacteria can play an obvious blocking role in small pore throat diameter, adapting to a lower permeability reservoir, the effects of flooding is better in the polymer of lowerer molecular weight, which can improve the recovery above 8%.laboratory experiment and effect evatutation,etc,carried out field test in Gaotaizi reservoirs of oil-water transition zone.Injected microorganism and nutrition 9600m3, accumulative injection microbial suspension 80t, activated sludge water 400m3,with inorganic nitrogen and phosphorus 10.5t, molasses 16t to north 4-91-bing26 well,north 4-81-bing26 wellå’Œnorth 4-91-bing267well. the effect of field application showed that the input-out-put ratio is 1 to 8,accumulative enhancement were to 2743.8t, the average single well increases by392t,recovery increased 2.7%。(1)increased the amount of pre-protective–slug, adopting slug of inject bactera alternating injection, which can further improve the efficiency MEOR.Crude oil water emulsion of production , Such as the content of HCO₃^-1 and SO₄^2-abnormally increase which can be used as a reference in microbial flooding ;crude oil density, viscosity, gel wax content, sulfur content, molecular weight, all-hydrocarbon components ,group composition can be used as indicators of micro-organisms of the different effects of crude oil.