DOWNHOLE ELECTRIC HEATER BUILT INTO THE TUBING STRING Russian patent published in 2016 - IPC E21B36/04 E21B43/24 

FIELD: oil and gas production.

SUBSTANCE: invention relates to oil and gas production and is intended for flow heat treatment of formation fluid as productive formation in the bottom hole zone (BHZ) with high-viscosity oil and in the tubing string (TS), in order to reduce oil viscosity and exclude paraffin plugs formation. Downhole electric heater built in the TS column, includes TS, end sections which are made with possibility of installation in the TS column, casing concentrically arranged relative to TS, and heating elements arranged between mentioned tube and casing, connected to power cable. Casing is metal and is installed relative to TS with formation of circular space, sealed on the side ends of the casing. Wherein mentioned circular space is equipped with at least one heating element with heat-resistant insulator, in the form of arc-like plate electrode, lower end of which is submerged into electrolyte, partially filling the circular space. Upper end of the electrode is connected to power cable through input unit into circular space of the cable. Heater is equipped with at least one sensor of measuring control, power supply and indications receiving of it is carried out through the mentioned current feed cable.

EFFECT: technical result is high reliability and efficiency of operation due to simplification of design and increasing heat transfer, while ensuring versatility due to possibility of its use for thermal treatment of formation fluid in BHZ and TS.

13 cl, 3 dwg