Study On Preparation And Resistance Of Foamed Oil

Heavy oil is characterized by high viscosity and easy solidification, which has brought great difficulties to its recovery and transportation. When phenomenon of foamy oil occurs during the cold heavy oil production, the reservoirs always exhibit abnormal excellent production characteristics. Therefore, large amount of studies about foamy oil have been done by domestic and foreign scholars, but all aspects of the studies are about the underground condition. Methods for foamy oil preparation were proposed in this paper, and the resistance characteristics of foamy oil in horizontal pipes were analyzed. The work in this paper has certain practical significance to explore the new heavy oil flow drag reduction method.On the basis of of research advance investigation on foamy oil home and abroad, the basic properties of two heavy oils which are from JiQi distract (JQ) and TaHe field (TH) respectively were measured. Based on the the influences of heavy oil viscosity, surfactant type and concentration, oil-water ratio and environmental temperature, foamy oil with high stability was screened out by using Waring Blender method. And the basic properties of foamy oil, including foam mass, density, macrosopic and microscopic morphology and rheological properties were evaluated. According to the foam formulations screened out by Waring Blender method, foamy oils were prepared in high-pressure system in order to explore the feasibility of foamy oil transportation. By using the self-developed horizontal pipeline system, the pressure drop of foamy oil under different pipe diameter, temperature and flow rate were tested, the rheological models of foamy oil under the pipeline condition were determined, the resistance characteristics were anylazed, the influences of different test methods on the rhelogical characteristics of foamy oil were evaluated, and finally the viscosity reduction effect of foamy oil were evaluated.The results show that:JQ and TH heavy oils belong to ordinary heavy oil with low water content, and the viscosity, desity, asphaltene and resin content of TH heavy oil are higher than those of JQ heavy oil. When the foamy oils were prepared by Waring Blender method, JQ heavy oil+1.5g/L ABS+2.5g/L SF-1can produce the most stable foamy oil, while TH heavy oil+2.0g/L ABS+1.5g/L lauryl alcohol can produce the most stable foamy oil. When the foamy oils were prepared by high-pressure system, and the original fluids were pure heavy oils, the bubble produced in the heavy oil can provide some impetus to the flow of the fluid, but the impetus is far from enough. When the original fluids were a mixture of water, oil and active agents, and only the pressure energy exists, the fluid produce little foam, and the ability of carrying heavy oil is too weak to form uniform foamy oil. It needs to introduce mechanical energy to form homogeneous foamy oil fluids. The rhelogical characteristics of foamy oil, produced by Waring Blender method, under the pipeline condition is closer to power-law model, and followed by Bingham model. The friction coefficient formulas of power-law fluid and Bingham fluid were fitted, which can applied to the foamy oil horizontal pipe laminar flow, Re’<350, atmospheric pressure, temperature25-35℃and pipe diameter4-8mm. Under the same shear rate, the results of foamy oil shear stress were different when the test methods are different. The measured shear stress of rheometer is higher than the flow tube, and the measured shear stress of8mm pipe is higher than the4,5mm pipe. The apparent viscosity of foamy oil is much lower than the viscosity of heavy oil, and the viscosity reduction rate is over97%. But due to the presence of small bubbles, the amount of heavy oil is reduced under the same flow rate condition which leads to the reduction of pipeline efficiency. And there are follow-up problems such as degassing and dehydration. Overall, the study in this paper confirms the validity of the viscosity reduction effect of foamy oil, and further research about its application should be done in the future.