High power umbilicals for electric flowline immersion heating of produced hydrocarbons

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. Different methods of deploying the electrically heated umbilicals are also provided.

1 . An apparatus comprising an electrically heated composite umbilical means installed within a subsea flowline containing produced hydrocarbons as an immersion heater means to prevent waxes and hydrates from forming within said flowline and blocking said flowline, whereby said electrically heated composite umbilical means possesses at least one electrical conductor disposed within said composite umbilical means that conducts electrical current that is used to heat said electrically heated composite umbilical means within said subsea flowline, whereby said electrical conductor is surrounded by a composite material, and whereby said composite material is comprised of fibers of high strength embedded in a matrix material, whereby said fibers are selected from carbon fibers, aramid fibers and glass fibers, and whereby said matrix material is selected from thermoset resins and thermoplastic resins, whereby said thermoset resins include epoxy and vinyl ester, and whereby said thermoplastic resins include PEEK, PEKK, and nylon. 
     
     
         2 . A method of installing an electrically heated composite umbilical means within a previously existing subsea flowline containing produced hydrocarbons to make an immersion heater means to prevent waxes and hydrates from forming within said flowline and blocking said flowline, whereby said electrically heated composite umbilical means possesses at least one electrical conductor disposed within said composite umbilical means that conducts electrical current that is used to heat said electrically heated composite umbilical means, whereby said electrical conductor is surrounded by a composite material, and whereby said composite material is comprised of fibers of high strength embedded in a matrix material, whereby said fibers include carbon fibers, aramid fibers and glass fibers, and whereby said matrix material includes thermoset resins and thermoplastic resins, whereby said thermoset resins include epoxy and vinyl ester, and whereby said thermoplastic resins include PEEK, PEKK, and nylon. 
     
     
         3 . A method of using an umbilical conveyance means to convey into an existing subsea flowline possessing produced hydrocarbons an electrically heated composite umbilical means used as an immersion heating means to prevent waxes and hydrates from forming within said flowline and blocking said flowline, whereby said electrically heated composite umbilical means possesses at least one electrical conductor disposed within said composite umbilical means that conducts electrical current that is used to heat said electrically heated composite umbilical means, whereby said electrical conductor is surrounded by a composite material, and whereby said composite material is comprised of fibers of high strength embedded in a matrix material, whereby said fibers include carbon fibers, aramid fibers and glass fibers, and whereby said matrix material includes thermoset resins and thermoplastic resins, whereby said thermoset resins include epoxy and vinyl ester, and whereby said thermoplastic resins include PEEK, PEKK, and nylon. 
     
     
         4 . A method of using an umbilical conveyance means to convey into an existing subsea flowline containing produced hydrocarbons an electrically heated umbilical means used as an immersion heating means to prevent waxes and hydrates from forming within said flowline and blocking said flowline, whereby said electrically heated composite umbilical means possesses at least one electrical conductor disposed within said composite umbilical means that conducts electrical current that is used to heat said electrically heated composite umbilical means, whereby said electrical conductor is surrounded by a composite material, and whereby said composite material is comprised of fibers of high strength embedded in a matrix material, whereby said fibers include carbon fibers, aramid fibers and glass fibers, and whereby said matrix material includes thermoset resins and thermoplastic resins, whereby said thermoset resins include epoxy and vinyl ester, and whereby said thermoplastic resins include PEEK, PEKK, and nylon.