STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

FIELD OF INVENTION

The present disclosure relates generally to downhole heating systems for boosting production in heavy oil wells. More specifically, the present disclosure is directed to the installation of a heater cable technology below a permanent downhole electrical connector system installed onto a permanent completion.

BACKGROUND OF THE INVENTION

Cold flow oil wells often produce oil at relatively low rates due to their low viscosity. A downhole pump, such as those provided in the retrievable ESP systems offered by AccessESP (Houston, Tex.), has to “pull hard” to enable flow, which also tends to pull in water high volumes of water, if present. Therefore, downhole heaters, such as those offered by Salamander Solutions (Houston, Tex.) are available to provide a small boost in temperature that will decrease the oil viscosity and simultaneously increase the oil production (by up to 5 times or more) and decrease water production. For example, a custom-designed Salamander BoostWell™ heater can be deployed in long horizontal cold flow wells to profitably increase oil production and provide this benefit for the life of the well: up to ten years or longer. Recent advances in drilling technology have enabled ever longer horizontal wells to be drilled enabling cold flow reservoirs that were formerly uneconomic to be developed. These long horizontal cold flow oil wells are ideal targets for the use of downhole heater technology, such as Salamander's BoostWell™ heater technology.

However, these downhole heaters require a source of electrical power. Currently, these downhole heating systems are deployed via coiled tubing and rely on power provided from the surface. For example, in a traditional permanent completion, these heaters can be deployed downhole through the completion using coiled tubing deployment. However, when the heater is in place, access to the well is limited, e.g., a retrievable ESP system cannot be installed into or retrieved from a permanent completion where such downhole heating systems have been installed. Therefore, there exists a need to provide for installation of a downhole heating system while still permitting access to the downhole permanent completion.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, there is disclosed a heated downhole permanent completion system comprising: an upper annular connection port (ACP) installed in the wellbore; a first power cable directed from the surface to the upper ACP to provide electrical power to the upper ACP; a lower ACP installed in the wellbore below the upper ACP, and being connected to the upper ACP by a spacer tube; a second power cable directed from the surface to the lower ACP to provide electrical power to the lower ACP; and a heating assembly connected to the lower ACP in the wellbore and receiving power from the second power cable, the heating assembly providing heat to the wellbore.

The heating assembly preferably is retrievable and can be conveyed to the lower ACP by coil tubing.

In one embodiment, the heating assembly further comprises: a plug arm assembly for establishing a mechanical and an electrical connection between the retrievable heating assembly and the lower ACP, the plug arm assembly having an upper end connectable to the lower ACP and a lower end; a section of coil tubing connected to and extending from the lower end of the plug arm assembly, the section of coil tubing having an inner bore; and an electrical heating element within the section of coil tubing inner bore, the electrical heating element electrically connected to the lower ACP.

The electrical heating element may comprise a mineral insulated heater cable.

The heated downhole permanent completion system may further comprise a retrievable ESP assembly mechanically and electrically connected to the upper ACP.

There is also disclosed a method of heating a downhole permanent completion system comprising the steps of: installing an upper annular connection port (ACP) in the wellbore, the upper ACP being supplied with electrical power via a first power cable directed from the surface to the upper ACP; installing a lower ACP in the wellbore, the lower ACP being supplied with electrical power via a second power cable directed from the surface to the lower ACP, the lower ACP being installed in the wellbore below the upper ACP, and being connected to the upper ACP by a spacer tube; conveying a heating assembly into the wellbore and mechanically and electrically connecting the heating assembly to the lower ACP in the wellbore; and generating heat from the electrical heating assembly into the wellbore. In this method, the heating assembly may be conveyed into the wellbore via coil tubing. When coil tubing is used to convey the electrical heating assembly to the lower ACP, the coil tubing may thereafter be removed from the wellbore after the step of installing the electrical heating assembly to permit further access to the upper ACP, for example, to permit mechanically and electrically connecting a retrievable ESP assembly to the upper ACP.

In this method, the heating assembly may be retrievable, and be conveyed by coil tubing.

In one embodiment of the present method, the heating assembly further comprises: a plug arm assembly for establishing a mechanical and an electrical connection between the retrievable heating assembly and the lower ACP, the plug arm assembly having an upper end connectable to the lower ACP and a lower end; a section of coil tubing connected to and extending from the lower end of the plug arm assembly, the section of coil tubing having an inner bore; and an electrical heating element within the section of coil tubing inner bore, the electrical heating element electrically connected to the lower ACP. The electrical heating element may comprise a mineral insulated heater cable.

