Abstract: Methods and apparatus for installing electrically heated composite umbilicals within subsea flowlines containing produced hydrocarbons as immersion heaters to prevent waxes and hydrates from forming within the subsea flowlines that could block the flowlines. The electrically heated composite umbilicals may be installed, or retrofitted, into existing subsea flowlines. Such retrofitted electrically heated composite umbilicals provide an alternative for previously installed, but failed, permanent heating systems. A hydraulic pump installed on the distant end of an electrically heated composite umbilical also provides artificial lift for the produced hydrocarbons. Other electrically heated umbilicals used as immersion heaters are described. Such immersion heater systems may be removed from the well, repaired, and retrofitted into flowlines without removing the flowlines. Near neutrally buoyant electrically heated umbilicals are described which may be installed great distances into flowlines.

Abstract: The method of providing in excess of 60 kilowatts of electrical power to the electrical motor of a subterranean electric drilling machine through a substantially neutrally buoyant composite umbilical containing electrical conductors to reduce the frictional drag on the neutrally buoyant umbilical. Drilling and casing subterranean monobore wells are contemplated to distances of 20 miles from a wellsite. For drilling applications, the umbilical possesses a drilling fluid conduit. The umbilical also possesses high speed data communications such as a fiber optic cable or a coaxial cable that is used in the feedback control of the downhole electric drilling motor. Such umbilicals are also useful to provide power to remotely operated vehicles for subsea well servicing applications.