乳化降粘剂SB-2乳化稠油机理研究

A Mechanistic Study on Viscosity Reduction of Heavy Crude Oils through O/W Emulsion Formation with Anionic Surfactant SB-2

实验研究了用表面活性剂SB 2乳化稠油降低粘度的几个机理性问题。SB 2是胜利油田开发的稠油乳化降粘剂 ,为脂肪酸改性的具有多官能团的钠盐型阴离子表面活性剂。根据用duNo櫣ｙ法测定的表面张力曲线 ,SB 2在蒸馏水中的临界胶束浓度为 0 .16 g/L ,在模拟地层水 (TSD =15 .8g/L ,含Ca2 + 0 .6 g/L ,含镁 0 .2g/L)中的为0 .0 2 4 g/L。产自胜利油田不同区块 7口井、5 0℃粘度为 3.0× 10 3 ～ 3.3× 10 5mPa·s的稠油 ,与浓度 3～ 8g/L的SB 2地层水溶液在油水体积比 7∶3及一定温度 (5 0～ 70℃ ,视井温而定 )时形成粘度 <30 0mPa·s的O/W乳状液 ,稠油粘度较高时所需的SB 2浓度较高。用ESI MS方法测定了在 5 0℃形成的O/W稠油乳状液水相和油相中SB 2浓度 ,得到下述结果 :在相同稠油和油水比条件下 ,SB 2初始浓度较高时 ,乳状液水相和油相中SB 2浓度也较高 ,粘度不同的 2种稠油与同一浓度SB 2地层水溶液形成的乳状液 ,油水比越大 ,油相中SB 2浓度越小 ,水相中SB 2浓度则相同 ,油水比也相同时SB 2在油相中的浓度也相同。用微量热法测定了一种稠油与SB 2地层水溶液乳化时的热效应 ,乳化过程为放热过程 ,乳化热随水相SB 2浓度、油水比和乳化温度增高而增大。图 6表 1参 6。

An experimental study is conducted on the mechanmisms involved in emulsification and viscosity reduction by SB-2 of heavy crude oils (HCOs). SB-2, being developed for use in Shengli, is composed of a fatty acids modified and polyfunctionalities containing anionic surfactant in Na salt form. The critical micellar concentration of SB-2 in distilled water is of 0.16 g/L and in a simulation formation water (SFW) of TSD=15.8 g/L, Ca^(2+) content 0.6 g/L and Mg^(2+) content 0.2 g/L:-0.024 g/L. The HCOs from 7 wells of various districts of Shengli with viscosity at 50℃ in range 3-330 Pa·s and SB-2 solutions in the SFW of concentration 3-8 g/L from O/W emulsions with viscosity <300 mPa·s at oil to water volume ratio (OWR)7∶3 and at temperature ranged 50-70℃ and the SB-2 concentration required is higher with HCOs of higher viscosity. The SB-2 concentration in the oil and water phases, C_o and C_w, of the O/W emulsions formed at 50℃ is determined by using ESI-MS and following results are obtained: at equal value of OWR, the value of both C_o and C_w is higher when the initial SB-2 concentration in solution, C_s, is higher; for emulsions formed from 2 HCOs of different viscosity and SB-2 solution in SFW of equal concentration (10 g/L), the value of C_w is equal but the value of C_o decreases with increasing OWR and C_o value becomes equal at equal OWR. The thermal effect of emulsification of one HCO in SB-2 solutions in SFW is determined microcalorimetrically and it is shown that the process is exothermic one and the heat of emulsification increases with increasing SB-2 concentration, OWR, and experimental temperature.