Modeling The Interfacial Tension Of （CO₂+CH₄）/（CO₂+N₂）/（CH₄+N₂）+H₂O Gas/Water System Via SVR

In the exploration,production and processing of oil engineering,interfacial tension is a determinant of the capillary pressure,relative permeability and residual liquid saturation.So,accurate interfacial tensions need to be measured and predicted for the design and optimize of the oil production process and recycling process.However,because of the expensive experimental equipment and elaborate experimental process,the data of interfacial tension is relatively scarce.Thus,the interfacial tension of(N2+CO2)+H2O,(CH4+CO2)+H2O and(CH4+N2)+H2O systems have been simulation via the Support Vector Regression approach which is developed with the import of Particle Swarm Optimization,and constructed SVR models for interfacial tensions.The main tasks of this thesis are as follow:(1)Investigated the interfacial tension of ternary systems(CO4+N2)+H2O and(CH4+CO2)+H2O,constructed SVR models for each system,and both of the SVR model achieved great agreement with experimental results with a small mean absolute percentage error of 0.29%,0.48%,respectively.Besides,the SVR model of(CO4+N2)+H2O system is better than the model built via Linear Gradient Theory as the MAPE of LGT model is 1.29%.(2)An integrated,precise and smooth SVR model was established solely based on the measured binary subsystems IFT data via the SVR which combined with PSO,achieved excellent agreement with experimental results since the mean absolute percentage errors(MAPEs)of binary systems(N2+H2O,CH4+H2O),and ternary system(CH4+N2)+H2O reached 0.30% and 0.79% respectively,and the overall MAPE is 0.60%,whereas the overall MAPE is 3.42% achieved by the LGT.(3)Analyzed the tendency of the interfacial tension along the changes of temperature,pressure or gas composition.Compared and investigated the similarities and differences of the IFTs’ tendency of all three gas-water systems.The results show that all of three SVR models are with high accuracy and valid predictive capacity.Under the conditions of different temperature,pressure and gas composition the trend of IFTs in(CH4 + N2)+ H2 O system is more simple and consistent,while that of(CO4+N2)+H2O and(CH4+CO2)+H2Osystems are more complicated.The reason which caused the phenomenon were likely to be the increase of content of CO2 in H2 O.In addition,a essential calculated supplementary dataset on interfacial tension of ternary system(CH4+N2)+water from 295 K to 373 K and pressures up to 30 MPa at every 2 K and 0.5 MPa via PSO-SVR model was provided,which would have practical significance of the reference value of engineering application.