| Thermal recovery is the most effective methods for heavy oil recovery. In the process of steam injection, there will take place aquathermolyis between steam and heavy oils. The results of aquathermolysis of heavy oil will lead to the amount of saturates and aromatics increase, resin and asphaltene decrease. It provides the theoretical basis for downhole catalytic upgrading of heavy oil. Base on the study of the feasibility of aquathermolysis for heavy oil from Liaohe oilfield, a suitable catalyst was selected. The reaction condition and influence factors are also investigated in detailed. After a number of experiments, the reaction mechanism of aquathermolysis was postulated. The technology was applied successful in Liaohe oilfield. The main works and innovations in this paper include as following:(1) Systemic study of the feasibility of aquathermolysis for Liaohe heavy oilIn order to study on the feasibility of aquathermolysis, the effects of reaction temperature, reaction time, and water content on the composition, viscosity and average molecular weight of heavy oil and asphaltene are investigated in detailed. And the yield of gases in the reaction were studied, especial the conversion of resin and asphaltene from heavy oil are investigated. The results show that, under the condition of steam injection, aquathermolysis can take place. The viscosity of heavy oil will reduce by 28% when undergo aquathermolysis for 36 hours under 240"C, and the compositions of the heavy oil are changed clearly after aquathermolysis. These changes are including: the saturates and aromatics increase while resin and asphaltenes decrease. The VPO results show that the average molecular weight of heavy oil and asphaltene from heavy oil are also decrease, the content of sulfur and oxygen decrease. The NMR and IR results show that, after aquathermolysis, the structure of heavy oil change a lot. All these results indicate that the heavy oil from Liaohe oilfield can undergo aqauthermolysis under steam stimulation.(2) Study on the catalytic aquathermolysis of heavy oil in detailedAfter studying of the feasibility of aquathermolysis, the catalysts for aquathermolysis are made from ores, which contains many type of heavy metal, such as nickel, vanadium and cobalt and so on. The properties of catalysts are measured and the aquathermolysis reaction behaviors were studied. The effect of reaction temperature, reaction time, concentration of catalyst and water content on the composition, viscosity, average molecular weight of heavy oils are investigated. The structures of heavy oils were detected by means of NMR and IR. The results show that the catalyst can accelerate the aquathermolysis of heavy oil and shorten the reaction time. When there is catalyst, the viscosity of reacted oil decrease by 80%. The SARA and VPO results also indicate that the structure of heavy oil were changed after aquathermolysis when catalyst existence in the reaction system.(3) The effect of minerals and hydrogen donor additive on catalytic aquathermolysisThe synergetic effect of mineral and hydrogen donor additive on the viscosity, compositions of heavy oils are studied. The results show that the mineral can accelerate the aquathermolys of heavy oil under the steam injection condition. And the hydrogen donor additive can terminate the active chains formed in the process of aquathermolysis of heavy oils, thus compress the regress of viscosity of the reacted oils. So keep the viscosity low after aquathermolysis.(4) Systemic study on the mechanism ofaquathermolysisfor heavy oilsIn order to investigate the reaction mechanism of heavy oils, the model compounds were determined based on the heavy oil's properties. Thiophene and tetrahydrothiophene are the suitable candidates for model compounds for investigate the mechanisms of aquathermolysis. Based on the results obtained from the aquathermolysis of model compounds, the mechanism of aquathermolysis for heavy oils are postulated in this paper. The mechanisms of aquathermolysis for heavy oils are:...
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