Abstract: JWY is a kind of non- ionic surfactant which is synthesized using oil-wet compounds containing active hydrogen in the molecular structure, epoxyethane and epoxypropane. It has almost the same molecular structure and physical properties as S- 100, a completion pipe string cleaning agent developed by foreign countries and is capable of cleaning suspending oil sludge and separating oil and water. Field tests show that filtrated water with 2% of JWY can meet operation requirements.