The Screening And Performance Evaluation Of Oil Resistant Ternary Composite Foaming Agents

The screening and performance evaluation of oil resistant ternary composite foaming agents were carried out in Lab. Ternary composite foam systems were selected for profile controlling and flooding in high oil saturation and heterogeneous reservoir. Foam could improve sweep efficiency because of the high apparent viscosity and selective plugging performance. Meanwhile high interfacial activity of low tension surfactant could increase oil displacement efficiency. Therefore, the oil recovery of heterogeneous reservoir after polymer flooding could be increased significantly.Firstly, DFA100 was used to select the surfactants which have good foaming ability and foam stability when oil is exist from 10 kinds of traditional foaming agents. Dodecyl hydroxypropyl phosphate betaine(foaming betaine for short) and fluorocarbon 101005 were screened out. Then the relationship between surfactant performance and interfacial rheological property was studied through comparing the interfacial dilational modulus, shear modulus, interfacial viscosity and other parameters of different surfactants.Secondly, the selected oil resistant foaming agents were mixed with oil displacement agents and alkaline, such as petroleum sulfonate, heavy alkyl benzene sulfonate, NaOH,Na2CO3, and then the best oil resistant and low tension foaming formula: 0.15% foaming betaine +0.15% heavy alkyl benzene sulfonate +1.2% NaOH +1500mg/L polymer was screened out through foam performance and interfacial tension evaluation.Thirdly, the foam flooding experiments in artificial heterogeneous cores were conducted and injection pressure, oil recovery and water cut were analyzed under condition of different variation coefficient and oil saturation. Foam system has a good adaptability to heterogeneous reservoir, the oil recovery exceeds 20% and increases with the increase of variation coefficient. When residual oil saturation ranges from 20% to 50%, foam system has an excellent flooding efficiency and oil resistant property.Finally, two parallel tube core model displacement experiments were conducted with different permeability contrast. It is indicated that the applicable permeability contrast extent of foam system is less than 10:1 from experimental results.