| Heavy oil and gas resources account for a large proportion in the oil-field. So the oil industry has been facing a problem that how to explore heavy oil effectively and make it to be available reserves. In recent years, Thermal / Foam oil recovery technique has developing rapidly. Under laboratory conditions and make the frother (DHF) used in Gudao oilfield as a model sample, the foam performance using the Waring– Blender puddling process was evaluated, and the influence of formation temperature, hardness, salinity, ions and their concentration, pH on the foam properties were investigated. The experimental results shows that the best frother concentration is 0.5%, the best foaminess temperature is 55℃, the good applicable formation conditions were: salinity less than 20000mg·L-1, hardness less than 240mg·L-1, formation pH=8-10; It was also found that, concentration of sodium ions greater than 200mg·L-1 that will result in foaming plunge, calcium ions and magnesium ions have great influence on the foam stability, and calcium ions have greater influence than magnesium ions.Under the Simulation of the on-site field conditions, heavy oil and its fractions influence on the foam system's performance and foam system's influence on the composition and structure of heavy oil, colloidal properties, interface properties with thermal effect were investigated. It was found that, the addition of heavy oil will reduce the stability of foam, and heavy component's impact on foam properties is greater than light component. For four fractions of heavy oil, asphaltenes have the best impact on the performance of the foam, followed by the colloid, saturated hydrocarbon and aromatic hydrocarbon. Under the thermal effect, the foam will reduce the oil-water interfacial tension, the higher the temperature and the more the dosage of frother, the smaller the oil-water interfacial tension. Foam and thermal's effect can affect the oil's physical and chemical qualities, undermine the colloidal stability of heavy oil. higher temperature can reduce the starting point of asphaltene coagulation, and result in the asphaltenes became easy to precipitate. It can also increased the asphaltene content and molecular weight, and the resin / asphaltine decreased, all of which make it difficult to drive oil. However, more foam agent can increase the starting point of asphaltene coagulation, Colloidal stability of the heavy oil changed for the better. At the same time, the addition of foam agent changed the structure and composition of heavy oil, the asphaltene content decreased, the resin / asphaltine increased and the asphaltines'molecular weight reduced, all of which were conducive to flooding. Foam has little effect on the rheology of heavy oil.Based on the study of DHF used in Gudao oilfield, a new type of highly efficient foam system was triturated. It was made up of foaming agent, foam stabilizing agents and auxiliary components. The performance of this foam system at room tempreture was: foam volume for 660mL, half-life for 250s, and foam volume of 310 mL, half-life for 175s at high tempreture. temperatures resistance high up to 300℃, low temperature performance was better than DHF and high temperature performance Considerable to DHF.
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