Customized Subsea Production Flowline Cleanout with Coiled Tubing from a Floating Production Storage and Offloading Vessel

Abstract

Abstract The recovery of a pipeline inspection gauge (PIG) left in a subsea production flowline in an unknown location after a failed cleaning and inspection operation is discussed. Combined with paraffin deposits, the production flowline of the best offshore producer in northeast Brazil was completely blocked. Extensive planning was necessary to spot the coiled tubing (CT) equipment to accommodate the deck configuration of the floating production storage and offloading (FPSO) vessel and to overcome dimensional and load capacity limitations. A customized extendable jacking frame was manufactured to support the CT injector and provide room for a work window. This fit-for-purpose rigging was necessary to enable the viability of the cleanout in the production flowline of the well. CT operation modeling software was used to analyze the hydraulic and force simulations to verify that the CT would reach the target depth with optimal jetting efficiency and would tailor the cleanout methodology. Paraffin was successfully cleaned from the flowline, and the PIG was released and recovered on surface. The CT was efficiently and safely rigged up on a FPSO without any nonproductive time or service quality issues. The versatility of CT services to not only deliver intervention services on conventional wells but to also adapt to rig up in extreme geometries and environments are showcased along with how CT services can be applied to flowline interventions. For this case, a customized CT frame was manufactured to overcome the challenges of rigging up on a vessel with extremely limited deck space and load capacities and restoring hydrocarbon production after a failed PIG procedure.