Surfactants For Crude Oil Emulsion Viscosity Reducing And Oil Resistant Foaming

A series of alkyl phenol polyoxyethylene glycidyl ether (NP-n-O) and alkyl phenol polyoxyethylene ether hydroxypropyl sulfonate (NP-n-S) were synthesized to explore the emulsifying viscosity reduction. The optimum conditions of sulfonation are gotten through orthogonal experiments, the ratio of alkyl phenol polyoxyethylene glycidyl ether and sodium bisulfite 1:1.5,100℃, and 6h.The effects of concentrations of the synthesized surfactants, pH values, emulsifying temperature (40℃ and 60℃) and water content on emulsification viscosity reduced and stability of emulsion to Venezuela’s Orinoco heavy oil were investigated. Take the water diversion ratio of emulsion at reservoir temperature (55℃) in 30 days as index, the results show that, under the condition of 40℃, oil/water ratio 7:3 and surfactant NP-4-S concentration 0.5%, emulsion can be formed perfectly, with viscosity reduction rate running up to 99.69% and water diversion ratio in 30 days reaching 9.38%; while at 60℃ and oil/water ratio of 7:3, as NP-4-S concentration is 1%, viscosity reduction rate can reach 99.55% and water diversion ratio is merely 4.23% in 30 days. The mixture of NP-n-S, Polymer H and CBO at suitable concentration can greatly improve the emulsification viscosity reduction and emulsion stability, which makes the emulsion viscosity rate over 98%. Moreover, the emulsion of H-NP-7-S-15, H-NP-7-S-30, H-NP-10-S-15, H-NP-10-S-30, C-NP-4-S-15, C-NP-4-S-17, and C-NP-7-S-17 can be stable at least 30 days without water emerging.Considering Venezuela’s Orinoco heavy oil as oil phase, the oil resistant foaming performance and foam stability of single surfactant and surfactant compounds at room temperature (20℃) and reservoir temperature (55℃) were investigated. The results showed that under the conditions of ambient temperature, in different proportion of crude oil and naphtha mixture as oil phase, foaming solution has presented excellent oil resistant foaming performance, and foam volume was not only more than five times of the foam liquid, but also the stable time over than 120 min. With the increase of naphtha content in mixed oil phase, foaming performance degraded. After added polymers, they could obviously improve the foam stable time over than 360 min. When the surfactant with CBO compound as foaming solution, not only the foaming volume increased, but also more uniform fine foam gernerated. Further research demostrated that mixing the compounds of surfactant, the CBO and polymer H as foaming solution, foam showed preferable oil resistance and temperature resistance. Then, we studied the optimal conditions of foam performance at reservoir temperature (55℃). The results indicated that foaming volume was more than five times of the foam liquid, and the foam could decay time about 120 min with remaining triple foaming liquid, on the conditions of NP-4-S:CBO=4:1(total concentration:0.5%),0.1% polymer H.