| abstract |
An electrical heating method and apparatus for minerals wells having a metallic fluid admission section located adjacent a hydrocarbonaceous reservoir of a heterogeneous reservoir that has at least two longitudinally spaced producing intervals having different thermal heat transfer characteristic. The method includes providing a downhole electrically energized heater having at least two independently controlled heating elements spaced longitudinally apart from each other. At least one of the heating elements is positioned near a first of the producing intervals adjacent the fluid admission section. The second of the heating elements is positioned near a second of the producing intervals adjacent the fluid admission section. Electrical energy is supplied to each of the heating elements to increase the temperature of the producing interval near each of the heating elements where the temperature is measured adjacent each of the heating elements and the quantity of electrical power supplied to each of the heating elements is controlled in accordance with the thermal transfer characteristic of each of the producing intervals to realize a specific temperature need near each of the heating elements. The apparatus includes a downhole electrically energized heater having at least two independently controlled heater elements. Electrical conductors conduct a source of electrical energy located above the ground near the top of the well to the heater elements to independently supply energy to each of the heater elements. A temperature sensor is provided for each of the heater elements to measure the temperature adjacent each of the elements and a control is provided for varying the quantity of electrical energy to supply to each of the heater elements in accordance with a specific temperature near each of the heater elements. |