| At present,most of China's oil fields have entered the stage of tertiary oil recovery.At present,the most widely used surfactants are mainly divided into two types:anion surfactant and nonionic surfactants.Their application conditions are harsh and they are highly dependent on alkali.Therefore,it is urgent to explore surfactant systems with better physicochemical properties.In this paper,the heavy alkyl benzene strong alkali ternary system and sulfonate weak alkali ternary system are taken as reference systems.Through the evaluation of emulsification performance and oil displacement effect of the reference system,a method for evaluating emulsification performance and oil displacement effect of the ternary system is established.Then,the oil displacement effect and emulsification performance indexes are compared and analyzed,and a method for evaluating the relationship between emulsification performance and oil displacement effect is established.Secondly,other betaine surfactants with the same conditions and different types of additives are evaluated accordingly,and the sensitive emulsifying performance indexes that affect the oil displacement effect of betaine surfactants with different types of additives are preliminarily screened out.Then,according to betaine surfactants of different additive types,the concentration of the surfactant or the dosage of the additive are changed to carry out corresponding evaluation,verify the correctness of sensitive indexes,and obtain quantitative results.The results show that:?1?for ternary composite system,lower interfacial tension is conducive to improving recovery ratio of chemical flooding;The lower the water diversion ratio,the higher the recovery ratio of chemical flooding.The smaller the stability index is,the slower the coalescence rate of the system is,and the more favorable it is for oil displacement.Within a certain viscosity range,the lower the viscosity,the higher the recovery rate of chemical flooding.The smaller the particle size of emulsion,the higher the recovery ratio.?2?For a single betaine main agent flooding system,the sensitive emulsifying performance index of the flooding effect is emulsion viscosity.The recovery ratio of chemical flooding is negatively correlated with the viscosity of emulsion.When the concentration of active agent is between 0.1%and 0.3%,the viscosity of emulsion drops from 110.4mPa·s to 85.4mPa·s,at the same time,the recovery ratio of chemical flooding increases by 1.49 percentage points.When the concentration of active agent is between 0.3%and 0.4%,the viscosity of emulsion increases from 85.40mPa·s to 92.31mPa·s,at the same time,the recovery ratio of chemical flooding decreases by 0.11 percentage points.?3?For the compound oil displacement system of betaine main agent and auxiliary agent I,the sensitive emulsifying performance index of oil displacement effect is emulsion viscosity.The recovery ratio of chemical flooding is negatively correlated with the viscosity of emulsion.When the dosage of additives is between10%and 30%,the viscosity of emulsion drops from 84.99mPa·s to 65.64mPa·s,at the same time,the recovery ratio of chemical flooding increases by 1.46 percentage points.When the dosage of additives is between 30%and 40%,the viscosity of emulsion increases from65.64mPa·s to 72.98mPa·s,while the recovery ratio of chemical flooding decreases by 1.02percentage points.?4?For the compound oil displacement system of betaine main agent and auxiliary agent II,the sensitive emulsifying performance index of oil displacement effect is:interfacial tension.The recovery ratio of chemical flooding is negatively correlated with interfacial tension.When the dosage of additives is between 10%and 40%,the interfacial tension increases from 8.98×10-3mN/m to 1.37×10-1mN/m,and the recovery ratio of chemical flooding decreases by 1.24 percentage points.?5?For the compound oil displacement system of betaine main agent and auxiliary agent III,the sensitive emulsion performance index of oil displacement effect is emulsion particle size.The recovery ratio of chemical flooding is negatively correlated with emulsion particle size.When the dosage of additives is between 10%and 30%,the emulsion particle size decreases from 48.90?m to 40.50?m,and the recovery ratio of chemical flooding increases by 1.69 percentage points.When the dosage of auxiliary agent is between 30%and 40%,the emulsion particle size increases from 40.50?m to51.20?m,while the recovery ratio of chemical flooding decreases by 0.93 percentage point. |
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