Chemical injector apparatus and method for oil well treatment

摘要

An apparatus for injecting a treatment chemical into an oil well produced using a subsurface pump, preferably a subsurface rotary pump, is described. Crude oil is pumped upward from a subsurface oil production zone through a central production pipe in the well. A small portion of produced fluid is diverted through a by-pass line interconnecting the production pipe and the annular space of the well between the production pipe and the well casing. A venturi nozzle comprising a throat of reduced diameter is mounted in the by-pass pipe. A suction pipe interconnects a chemical storage container containing a treatment chemical with the nozzle throat. Under the action of the venturi nozzle a suction pressure is created in the nozzle throat whereby the treatment chemical is drawn through the suction pipe and mixes with the fluid in the by-pass line thereby delivering the chemical to the well annulus. The chemical flows down the annulus under the action of gravity, mixes with the fluid in the well, and is drawn into the production pipe at the pump inlet thereby treating the fluid in the well.