Research and Application of High Efficiency Well Flushing Fluid System

Well workover is an indispensable production link in oilfield development. Hot washing is an important measure to maintain normal production of oil wells before well workover. Based on the principle of “source control” of pollution prevention and control in oilfield production, this paper guarantees that crude oil does not fall to the ground, adopts the way of adding chemicals to wash wells, takes the wellbore production string as the starting point of prevention and control, and uses the unique properties of surfactants, develops a new type of well-washing fluid system, which can effectively reduce the field dispensing temperature. The system can wash oil more than 90% at 65 °C, and the concentration of chemicals is 0.6%. The interfacial tension between oil and water decreases to 10–4 MN/m. Effectively avoid oil pollution from wellbore when workover operation, resulting in surface and environmental pollution. The expected goal has been achieved through well washing experiments of more than 10 oil wells before workover operation.