Abstract: Laboratory experiments have been conducted on emulsions of extra-heavy crude from block BQ10 in Gucheng oilfield.It was found that the phase inversion point of the emulsion was about 68%,i.e.,when water fraction Φ≥68%,the emulsion will change from W/O to O/W.After phase inversion,friction between crude and pipe wall and the internal friction of crude will change to that between water and pipe wall,and between waters.As a result,viscosity and friction loss can be reduced greatly.Field tests by reinjecting the produced water back into the gathering system of the same cell confirmed the laboratory results.This re-injection differs from both conventional hot water injection and treated-produced-water injection.It has some advantages over injection of light oil.Application of this easily-operated technique may efficiently reduce the back-pressure of wells,cut production cost,improve production efficiency and economic benefit.

Key words: heavy crude, oilfield, waste water, gathering process, viscosity reduction, test, back-pressure emulsion

摘要： 通过对河南古城油田BQ10区特超稠油乳状液的室内试验分析,指出该种乳状液的实际相突变点为68%左右,当相浓度Φ≥68%时,以W/O型为主的乳状液突变为以O/W型为主的乳状液.乳状液变型后,原油与管道内壁之间的摩擦以及原油之间的摩擦转变为水与管道内壁及水与水之间的摩擦,从而大幅度降低其粘度和摩阻损失;通过对古城BQ10区特超稠油区块单元内部污水回掺降粘集输的现场试验,证明与室内试验分析得出的结论相符合,说明区块单元污水回掺不同于常规的掺热水,也不同于掺联合站处理过的净化污水,它优于单井掺稀油.最后指出该工艺可有效地降低井站回压,方便生产管理,降低开采成本,提高采油效率和经济效益,具有低耗节能的优点.

关键词: 稠油, 油田, 污水, 集输流程, 降粘, 试验, 回压, 乳状液