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

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