The Research Of Activation Conditions For Anaerobic Microbial Degradation Of Heavy Hydrocarbons

The reservoir can not be effectively utilized but can converte to gas reservoirs by metabolicaction of anaerobic microorganisms, and harvest as gas reservoirs has become an important research direction today. Use Shengli Oilfield heavy-oil for this study, with produced water as inoculum, investigated glucose, molasses, soluble starch, and sodium acetate four kinds of carbon sources; sodium nitrate, ammonium chloride and urea three kinds of nitrogen; dipotassium hydrogen phosphate, potassium dihydrogen, both 1:1 mix three kinds of phosphate and trace elements Fe2+, Co2+, Ni2+ to activated the anaerobic microorganisms in the reservoir, accelerated the process of heavy hydrocarbons anaerobic degradation and into organic hydrocarbon gases. Through single factor experiment to find the best carbon source is glucose, the best dosage is 0.7%(w/v), training 270 d produced organic hydrocarbon gases 220.94umol; Optimum nitrogen source was ammonium chloride, the optimum concentration is 400mg/L, training 240 d produced organic hydrocarbon gases 42.40umol; The best source of phosphorus is potassium hydrogen phosphate,the optimum concentration is 100mg/L, training 240 d produced organic hydrocarbon gases 20.76umol; The optimum concentration of Fe2+ is 1.1mg/L training 270 d produced organic hydrocarbon gases 130.36umol; The optimum concentration of Co2+ is 0.8 mg/L training 270 d produced organic hydrocarbon gases 178.47umol;The optimum concentration of Ni2+ is 0.09 mg/L training 270 d produced organic hydrocarbon gases 163.65umol;Controlled trial training 270 d only produced organic hydrocarbon gases 18.74 umol.On the basis of single factor test,through Response surface methodology to study the trace elements glucose, dipotassium hydrogen phosphate and ammonium chloride activation of endogenous microbial reservoirs, accelerating heavy hydrocarbons anaerobic biodegradation produce organic hydrocarbon gases. Use glucose, dipotassium hydrogen phosphate and ammonium chloride concentration as the independent variable, training 270 d gas production as the dependent variable, research each variable and the interactions on gas production,get the quadratic polynomial regression equation prediction model. The results showed: glucose, dipotassium hydrogen phosphate and ammonium chloride concentration and anaerobic degradation of heavy hydrocarbons produced hydrocarbon gases are significantly correlated, typical analysis found the optimal activation conditions of promote heavy oil anaerobic degradation produced hydrocarbon gas is adding 0.78%(w/v)of glucose, ammonium dosing 420.33mg/L, dipotassium hydrogen phosphate 90.64mg/L. Under this condition, training 270 d, the theoretical value gas production reached 278.73 umol, verification tests get the actual value is 276.69umol; Analysis the changes in microbial community before and after the activation by PCR-DGGE technology. Recovery the advantage bands and sequencing bands, successfully sequenced four strains,all of them belongs Bacillus sp, Strain Y1 and Environmental Samples are highest similarity, up to 99%;Strain P1 and Bacillus licheniformis are highest similarity, up to 98%;Strain P2 and Bacillus pumilus strain are highest similarity, up to 99%;Strain H2 and Bacillus circulans strain are highest similarity, up to 99%;On the basis of single factor test,throw Response surface methodology to study the trace elements Fe2+, Co2+ and Ni2+ activation of endogenous microbial reservoirs, accelerating heavy hydrocarbons anaerobic biodegradation produce organic hydrocarbon gases and research the microbial community composition after activation. Use Fe2+, Co2+ and Ni2+ concentration as the independent variable, training 270 d gas production as the dependent variable, research each variable and the interactions on gas production,get the quadratic polynomial regression equation prediction model.The results showed: Fe2+, Co2+ and Ni2+ concentration and anaerobic degradation of heavy hydrocarbons produced hydrocarbon gases are significantly correlated, typical analysis found the optimal activation conditions of promote heavy oil anaerobic degradation produced hydrocarbon gas is Ni2+ concentration of 0.10 mg / L, Fe2+ concentration of 1.1mg / L, Co2+ concentration of 0.86 mg / L.Under this condition, training 270 d, the theoretical value gas production reached 241.57 umol, verification tests get the actual value is 240.69umol; Analysis the changes in microbial community before and after the activation by PCR-DGGE technology. Recovery the advantage bands and sequencing bands, successfully sequenced three strains,all of them belongs Bacillus sp, Strain T1 and Bacillus thermoamylovorans are highest similarity, up to 97%; The similarity between strain H3 and Bacillus thermoamylovorans is up to 97%; The similarity between strain H4 and Bacillus vietnamensis is up to 99%.