Method for repairing flexible flow lines with a two-piece clamping collar and composite material

摘要

The present invention refers to a method to repair flexible flow lines used in the petroleum industry. This method provides a means for quick and permanent repairs of birdcage-type failures (BC) in flexible ducts while they are in operation, without interrupting production flows. The technology proposed, because of its simple characteristics, eliminates the need for replacing the affected section and for allocating special vessels to perform the repair.

主权项

1. A method for repairing a flexible flow line duct using a two-piece clamping collar and composite material, comprising permanently repairing a birdcage failure of a damaged section of duct by applying an epoxy resin around the damaged section of duct and subsequently placing a two-piece clamping collar around the section, wherein the duct includes a steel mesh layer covered by an outer polymeric layer, and the birdcage failure includes a portion of the steel mesh becoming exposed through the outer polymeric layer,
the method including the following steps: 1) visually inspecting a state of repair of the outer polymeric layer of the damaged section of duct; 2) measuring a size of the birdcage failure; 3) determining a depth and temperature at a location of the birdcage failure, and a descent period of time to reach the location of the birdcage failure; 4) determining dimensional parameters of the damaged section of duct to be repaired; 5) thoroughly cleaning the exposed portion of steel mesh of the birdcage failure, as well as a surface of the outer polymeric layer of the damaged section of duct to be repaired; 6) arranging for manufacture of the two-piece clamping collar; 7) calculating a volume of epoxy resin required to repair the birdcage failure; 8) preparing the epoxy resin before the two-piece clamping collar is lowered to the damaged section of duct, which includes selecting a content of a curing agent of the epoxy resin based on the descent time calculated in Step 3, so that once mixed, the epoxy resin will arrive at the location of the birdcage failure sufficiently malleable to penetrate the exposed portion of steel mesh; 9) splitting a total volume of epoxy resin into two equal volumes, and respectively packing each of the two equal volumes in their own separate fabric bag, each bag comprising a warp of natural fibres; 10) attaching each bag of epoxy resin to an inside of each section of the two-piece clamping collar; 11) placing the two-piece clamping collar obtained in Step 10 in an ROV (Remotely Operated Vehicle); 12) reducing an operating pressure in the duct until the birdcage failure contracts and layers of the duct that are interior of the steel mesh are compressed; 13) lowering the two-piece clamping collar with the fabric bags filled with epoxy resin to the location of the birdcage failure, within the decent period of time calculated in Step 3; 14) placing the two-piece clamping collar around the damaged section of duct; and 15) securing said two-piece clamping collar with a means for fastening.