| In order to reduce viscosity, the technology of heavy oil injection steam catalyticcracking is a new method for heavy oil recovery. The technology foucs on applicationconditions of catalyst for reducing viscosity. The disadvantages for present technology are asfollows: higher temperature, not adequate time to contact between catalyst and heavy oil, andhigher rebound rate for cracking reaction, et al. The problems above lead to difficultlarge-scale field application. It is restricted to develop this technology.First of all, the physicochemical properties for five kinds of heavy oils from Shengli OilField are studied. The main factors to explain the changes of heavy oil viscosity are analyzedby gas chromatography and infrared spectra. The results are as follows: the content of colloidand asphaltene is high (more than50%). Hydrothermal cracking catalyst containing plenty ofactive sites are synthesized. It is concluded that reducing viscosity reaction for heavy oilsteam catalytic cracking is not great affected by high temperature water. In order to improveeffects of reducing viscosity reaction, the catalytic system composed of catalyst, strongoleophilic polymerization inhibitor and strong lipophilic nano-dispersant is developed.According to experiments, the best reaction ratio and conditions are as follows: reactiontemperature is200℃, catalyst dosage is0.3%, inhibitor dosage is3%, dispersant dosage is0.5%, the ratio of oil and water is8:2, pH value is7~8, and reaction time24h. The reducingviscosity rate of heavy oil is85.6%with the conditions above. With the results of field test forcommon catalyst and optimal catalyst system, the technology is feasible. It can improve thequality and productivity of heavy oil. It shows better benefits preliminary, and it is animportant supplement of injection steam method. At the same time, it is an important methodfor improving effect of injection steam. It is efficient to increase the production for oilfield. |
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