AUTOMATIC SELF-REGULATING HEATER FOR FLUID HEATING INSIDE WELL Russian patent published in 2007 - IPC E21B36/04 

FIELD: oil production, particularly heating, cooling, or insulating arrangements for boreholes or wells, for example for use in permafrost zones.

SUBSTANCE: heater is made as cable line including low-temperature cable and high-temperature, namely heating, cable. High-temperature cable comprises current-conductive cords connected with each other from the first cable end and are insulated to create termination unit. Another heating cable end is connected to power source. Cable line extends outside tubing string or cable is spirally wound around tubing string. Heater also has surface-based measuring-and-control unit made, for instance, as programmable frequency electronic control unit and downhole measuring unit. The downhole measuring unit includes at least one sensor (crystal resonator) to read thermobaric fluid parameters. Above sensors are adapted to convert actual temperature and/or pressure values into frequency and are connected with measuring-and-control unit by means of cable line. The sensors are installed on tubing string body and/or on connection clutch thereof depending upon place of fluid parameter measurement, namely inside tubing string and/or in hole annuity.

EFFECT: increased accuracy and reliability of oil production control due to possibility to control thermal field of the well, increased volume of obtained information concerning fluid state in hole annuity, inside tubing string and on outer tubing string surface along with simplified assemblage and operation.

11 cl, 2 dwg