METHOD FOR PRODUCTION OF BOREHOLE FLUID UNDER COMPLICATED CONDITIONS AND DEVICE FOR ITS REALISATION Russian patent published in 2012 - IPC E21B43/00 

FIELD: oil and gas industry.

SUBSTANCE: method includes pumping of a borehole fluid with a screw pump by means of a string of hollow rods placed inside oil well tubing - OWT with supply of a reagent to reduce viscosity of the borehole fluid. According to the invention, in process of pumping the borehole fluid flow is divided into two parts. One part of this flow is sent to a flow line, and the other one - into a line of return to the well bore. For this purpose the upper end of the hollow rod string is equipped with a flow separator of double-throttle type, the lower end of this string is equipped with a perforated coupling, and inside this string is equipped with a water-jet coupling. At the same time the reagent to reduce viscosity of the borehole fluid is supplied into OWT or into the hollow rod string, is mixed there with the borehole fluid and sent via the water-jet coupling and partially via the perforated coupling into the hollow rod string or OWT. The device comprises a screw pump, a hollow rod string, placed inside of oil well tubing, a unit for reagent supply to reduce viscosity of the borehole fluid, into a well with an injection line, a line of return to the well bore. According to the invention, the device is equipped with a borehole fluid flow separator of double-throttle type, which is installed on the upper end of the hollow rod string, the lower end of which is equipped with a perforated coupling, and inside this string is equipped with a water-jet coupling to suck the reagent to reduce viscosity of the borehole fluid. At the same time the borehole fluid flow separator is made with two conical cavities, which hold a stem with two cones capable of displacement and two bends for distribution of the borehole fluid into a flow line and a line of return to the well bore. The injection line is capable of supplying the reagent to reduce viscosity of the borehole fluid into OWT or the hollow rod string.

EFFECT: higher efficiency of oil production at a later stage of deposit development due to reduction of quantity of the required equipment for pumping of the borehole fluid and reduction of reagent losses during its pumping into a well to reduce viscosity of the borehole fluid.

2 cl, 3 dwg