Temperature limit for oil-gas-water mixed transportation in safety during oil production with special high water-cut

The water cut of crude oil in Daqing Oilfield increase continuously with oil production. The water cut in produced liquid of most oil wells of the oilfield is about 90%. With the increase of water cut, the energy consumption for gathering and transporting one ton of crude oil rises sharply. In order to gather and transport oil safely without heating and to reduce the energy consumption and production cost, a suit of testing equipments in Daqing Oilfield were equipped. The pressure drop and flow pattern of oil-gas-water mixture produced in the No.6 Oil Production Plant were tested under the conditions of variable temperature, water cut, liquid output and gas capacity. The tested result indicates that oil-gas-water mixture flow in the horizontal pipe belongs to impact flow when water cut exceeds 85%, and the amount of produced liquid is 11~105t/d, and the amount of gas is 40~60m~3/t, and the flow rate of oil-gas-water mixture is 0.2~2m/s, and the conversion rate of gas is 0.15~1.8m/s. The oil-water phase shows two patterns of oil phase floating on water and oil-in-water dispersed phase. The temperature limit for safe transportation of oil-gas-water mixture is 23℃ during special high water-cut stage of Daqing Oilfield without any medicament.It’s lower than condensation point.