Research On Desulfuration Visbreaking Mechanism And Field Conduct Program Of Extra-Heavy Oil From East Shan 6 Block In Shengli Oilfield

Heavy oil reserve is abundant in China. To produce this reserve effectively is difficult. Heavy oil chemical upgrading is one of the effective methods. The method of heavy oil down-hole chemical upgrading, which can solve the problem originally, is effective particularly. Some scholars have studied this method and done some field experiment on heavy oil from Liaohe oilfield. No research about this method in producing heavy oil from Shengli oilfield is reported. In this paper, the catalytic visbreaking and desulfuration of extra-heavy oil from Shengli oilfield is studied in the proximate conditions of cyclic steam stimulation.A super acid catalyst is prepared for catalytic visbreaking of heavy oil. After visbreaking, the viscosity of extra-heavy oil is reduced 55.9% in the optimum test conditions (260癈, 24hr). The optimum mass rate is: oil : water : cat. = 100 : 30 : 0.05. The C35 molecules, resin and asphaltene in extra-heavy oil is decreased after catalytic visbreaking. The C25 --C35 molecules, saturated and aromatic hydrocarbon in extra-heavy oil is increased after catalytic visbreaking. The result of IR spectrum analysis shows: the CH2/CH3 of extra-heavy oil is decreased from 3.45 to 3.05 and the fA of extra-heavy oil is increased from 0.301 to 0.364. This result confirmed that aromatic compound in extra-heavy oil had broken its side chain alkylation. This reaction can also be confirmed by such fact that saturated and aromatic hydrocarbon in extra-heavy oil is increased after catalytic visbreaking. The synergetic effect of catalyst and polymerization inhibitor, initiator, solvent, reservoir mineral, formation water in catalytic visbreaking of extra-heavy oil have been reviewed in this paper. The experiments results shows that any mass, except polymerization inhibitor, has synergetic effect with catalyst and enhanced viscosity reduction rate of extra-heavy oil.A desulfuration reagent is prepared for wet and oxidation desulfuration of extra-heavy oil. The sulfide content of extra-heavy oil reduced 58.2% after treatmented by this reagent (oil : water : reagent = 100 : 30 : 0.06, 260℃, 24hr). The viscosity of extra-heavy oil is reduced more than 80% and The sulfide content of extra-heavy oil reduced not less than 70% when catalyst and desulfuration reagent coexist in reaction system (220℃~260℃,24hr). The optimum mass rate is:oil : water : cat. : initiator : solvent ". NaVO3 : Na2CO3=100 : 30 : 0.05 : 0.3: 0.4 : 0.01 : 0.0015.In this paper, the field conduct program of extra-heavy oil down-hole desulfuration visbreaking is studied based on lab research. The research include: technical principle, operated parameter, effectiveness assessment.