Evaluation Of Multiple Rounds Dynamic Adsorption,plugging Performance And Displacement Efficiency Of Foam System

In order to study the effect of foam systems under the three different reservoir conditions in Jilin Oilfield,the effects of temperature and salinity on the foam properties and displacement efficiency of different types of surfactants were investigated by airflow method and oil-water interfacial tension measurement.And the adsorption properties of different systems in different reservoirs were analyzed by measuring the foam properties of the three stages of core dynamic adsorption.In addion,the foam properties of the produced fluids were measured at four migration distances to quantitatively analyze effective distance of the foam system.Next,A single tube and double tube parallel core flow experiments were carried out to measure the flow capacity of the foam.Finally,two parallel tube core model displacement experiments were conducted with five combination modes of slugs.The pressure and flow rate of high and low permeability cores was analyzed,and the effect of blocking and flooding was determined,and the slug size,combination mode and alternating times were clarified.The results show that two kinds of high-blocking efficiency foam systems and high-wash efficiency foam systems can be selected from nine kinds of foam systems by measuring the foam comprehensive index and interfacial tension for three reservoir conditions.A decrease of temperature can prevent the occurrence of the last few stepwise transitions,and the stratification stops at a larger thickness;higher film stability results.Addition of salt inhibits the ordering of ionic micelles because the added ions screen the electric double layer around the micelles,and the result is a decreased effective volume fraction of micelles.After several rounds of core adsorption,the foam system with fluorocarbon surfactants decreased uniformly after each adsorption,and the foam performance of hydrocarbon surfactants is significantly decreased after the first round adsorption.The interfacial tension of petroleum sulfonates and heavy alkyl benzene sulfonates decrease significantly after secondary adsorption,while the betaine type surfactants still maintain a low interfacial tension after three times of adsorption.The evaluation of foam performance under four kinds of migration distance show that the effective distance of the complex system of sodium dodecyl sulfate and fluorocarbon surfactant in Xinmu 146,Honggang Gaotaizi and Dalaoyefu are 80%,60% and 60%,respectively.The effective distance of the low tension betaine surfactant foam system in the three reservoirs are 80%,80% and 60% respectively.The lower the core permeability,the higher the reservoir temperature and water quality,the shorter the effective effect.The results of core flow experiments show that the correlation between the blocking ability of the foam systems and the different factors of geological conditions from high to low are: core permeability,temperature and salinity.The results of double tube parallel injection experiments show that by combining the high oil washing ability and the high blocking capacity foam system,the respective displacement schemes can be obtained when the three blocks reach the maximum recovery rate respectively.The recovery of low permeability cores is in the range of 17.1% ~ 10.6%.