交联聚醚破乳剂对胜利油田二元驱采出液破乳性能研究

Study on the emulsion-breaking performance of cross-linked polyether demulsifiers for the emulsion produced by surfactant/polymer flooding in Shengli oilfield

针对胜利油田二元驱采出液存在的破乳困难问题,将脱水型聚醚破乳剂(BP01,TA01和PA08)与清水型聚醚破乳剂(PEI01)交联,制备出交联聚醚破乳剂D-BP,D-TA和D-PA,研究了交联聚醚破乳剂的界面活性和对油水界面膜强度的影响,以及对二元驱采出液的破乳效果。结果表明,在三种交联聚醚破乳剂中,具有超支化结构的D-PA在油水界面上的吸附作用力最强,界面活性最高;D-PA对稀释原油与采出水油水界面膜的影响最大,其吸附在油水界面后形成的界面膜的扩张模量最低。D-PA破乳剂对W/O乳状液的脱水率达到94.4%,对O/W乳状液的除油率达到98.1%。更为重要的是,其能同步处理含W/O和O/W复杂乳状液。D-PA对含W/O和O/W复杂乳状液的综合脱水率高于98%,处理后污水含油低于30 mg/L,游离态聚合物保留率达到了94.8%,油水界面整齐,无乳化中间层,表现出良好的破乳效果。

In view of the difficulties in breaking the emulsion produced by surfactant/polymer flooding in Shengli oilfield,the cross-linked polyether demulsifiers D-BP,D-TA and D-PA were prepared by crosslinking polyether demulsifiers with dewatering function for water-inoil(W/O)emulsion and polyether demulsifier with oil-removal function for oil-in-water(O/W)emulsion.The interfacial activities of the three crosslinked polyether demulsifiers were investigated.Their effects on the oil-water interfacial film of emulsions were examined,and their emulsion-breaking effects on W/O and O/W emulsions were explored.The results showed that among the three cross-linked polyether demulsifiers,D-PA with hyperbranched structure had the strongest adsorption at the oil-water interface and showed the highest interfacial activity.D-PA had the greatest effect on the oil-water interfacial film formed by the kerosenediluted crude oil and produced water.The new film formed after D-PA adsorption at the oil-water interface had the lowest interfacial dilatational modulus.The dewatering rate of W/O emulsion by D-PA was 94.4%,and the oil removal rate for O/W emulsion from the same oilfield reached 98.1%.More importantly,the D-PA demulsifier was capable of simultaneously treating complex emulsions containing W/O and O/W types.The comprehensive dewatering rate by D-PA for the emulsion produced by surfactant/polymer flooding containing W/O and O/W was above 98%,and the oil content of the effluent after treated was less than 30 mg/L.The retention rate of polymer(HPAM)reached 94.8%,and the oilwater interface was neat and without emulsified intermediate layer.