TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAquathermolytic technology that involves upgrading heavy oil using chemical additives is introduced in this paper. Laboratory experiments were carried out under steam injection conditions to investigate catalysis of some metal species and synergetic effect of catalyst and hydrogen donor on aquathermolysis of Liaohe and Shengli heavy oils. As a result, significant reduction in viscosity and contents of asphaltene and resin was obtained, thus heavy oils were upgraded greatly. Then the mechanism of aquahtermolysis is discussed further. Additionally, the field test in Liaohe Oifield is introduced. The future is suggested in the end.

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Effects of surfactants on oil/water interface are studied using dissipative particle dynamics (DPD) at the mesoscopic scale. With a surfactant model, the effects of concentration of three types of surfactants, including ionic surfactant, nonionic surfactant, and the compound system of ionic and nonionic surfactant, on interfacial tension are analyzed in this study. Also, the distributions of interfacial tension and mean interfacial density are predicted. Simulated results indicate that the interfacial tension decreases with an increase of surfactant concentration. As the surfactant concentration increases to a certain value, the surfactant at the oil-water interface is saturated, and the interfacial tension will in-depend on surfactant concentration. It turns out to be that surfactants can be saturated just at the oil-water interface once its concentration reaches a certain value. A proper mixed ratio of compound system can reach a prime effect. Moreover, the inorganic salts can improve the interfacial efficiency of both ionic and nonionic surfactants, and lower interfacial tension. In addition, the temperature influences on surfactant aggregation behavior at the oil-water interface is discussed. Copyright Figure 1. Equilibrated morphology in oil/water system at different water content with nonionic surfactant ( a) water content of 10%; ( b)water content of 50%; (c) water content of 90% (The blue particles (W) represent the water beads, the red particles (O) represent the oil beads, the green particles (A) represent EO, the pink particles (B) represent PO).S. WANG ET AL.

In recent years, the sulfide in oil-water treatment system of Daqing Oilfield has brought serious problems, to induce electric dehydrator trip and waste oil recycle difficultly and eventually so severe as to prevent further oil productions. The treatment difficulty of wastewater with sulfide will increase, the oily wastewater after treatment will be deteriorated and induce the formation plugging. Meanwhile, the equipments and pipelines will also be seriously corroded. The authors studied the generation and distribution of sulfide in oil water treatment system in Daqing Oilfield and the field test was conducted in the dewatering and wastewater treatment system based on microbiological method. The results showed that the dynamic microcontrol technology could effectively prevent the generation and accumulation of aging oil, avoid frequent electric dehydrator trip, and decrease the labor quantity to ensure the normal production and meet the dehydration standards. The application of this method would bring better profit and environmental benefits for Daqing Oilfield.

The practice of enhanced oil recovery (EOR) technique shows that the study and application of biosurfactant flooding system have a vast potential for future development. The authors challenge the traditional idea that the oil displacement surfactant must have ultra low interfacial tension. By changing the wettability of reservoir rock as main target, the glycolipid biosurfactant compounded system was developed by enzyme-catalyzed method in laboratory, and a series of experiments had been done combining with reservoir physical measurement. The properties of the active system were characterized by interfacial characters, disbonded, seepage characteristics, antibiotic property, and oil displacement efficiency.