Genesis Pipeline Crawlers: Pigging the Unpiggable

Abstract Description The paper reviews the work of SIG Ltd. to deploy appropriate sensor systems for inspections in pipelines hitherto considered unpiggable. Application Many pipelines cannot be internally inspected because of reductions/changes in ID, extreme angles, 90-degree mitre bends, T- and Y-junctions or simply having access for pigs without a recovery point. They may be empty, gas filled, without flow or flow in the "wrong" direction and so large sections are unpiggable. SIG's range of high-powered, tethered, brush-tractor crawlers are delivery systems for applications including internal inspection, cleaning and, later, repair. The first 16" and 10" units of this game-changing technology start operations in Q3/4 2010 but this innovative drive-system can be configured to power units from 4-6" and to 42" or beyond. The brush-drive system copes with internal pipeline irregularities caused by corrosion, sedimentation and changes in ID. Articulated propulsion and sensor-carrying modules allow the vehicle to negotiate 90 deg bends. Only one access point is needed for both insertion and recovery as crawlers can reverse. Crawlers are designed as internal pipeline cleaning and delivery systems with extremely high traction (5-20 tonne pull) and long-range capability (4 -8 miles, depending on pipeline geometry). They operate independently of pipeline flow; with the flow (at the vehicle's own speed), against it and also with no flow in empty pipelines. High traction power allows them to work in vertical pipelines, allowing examination of risers, and to remain stationary for extended periods in any attitude to monitor regions of high stress, such as pipeline touchdown points, over time. Integrated operational payloads carried are designed to best address clients' requirements; multiple sensor packages can include MFL, UT, electromagnetic acoustic transducers (EMAT) or other pulsed EM and acoustic systems plus optical/laser systems and so reduce operational time and cost by performing several tests in one single pass. Results Full scale field trials/operations start October/November 2010; results will be incorporated into the final paper for OTC 2011. Significance Full operational capabilities of these vehicles will be detailed in the final paper confirming their usefulness in inspecting hitherto unpiggable pipelines.