Pesca Pubblicazione scientifica A Method of Protecting Subsea Wellheads Against Environmental Hazards FILONE TECNOLOGICO TEMA produzione e cattura RIASSUNTO ABSTRACTThis paper presents the evaluation of the risk of damage to subsea wellheadsfrom fishing gear and oil related objects. It lists the alternative forms ofprotection considered and the selection of the most cost effective type.Details are given of the design and installation of two protective covers inthe North Sea. It presents the development of the design based on experiencegained leading to the installation of a third cover in the same area. INTRODUCTIONIn the ten years development of oil resources in the North Sea there hasbeen a steady increase in the number of fixed offshore installations supportingthis activity. More sophisticated technology is now being applied in theattempt to reduce the capital cost of conventional platform installations andachieve early field production. With the evolution of reliable subsea control systems the economics ofsubsea wellhead completion have become increasingly attractive, both as a meansof achieving production from early exploration and delineation wells and as ameans of tapping reservoir extensions beyond the recovery area of the mainfield facility. Although some advocates of subsea completion techniques originally believedthat the sea bed provided a relatively secure and isolated environment for suchequipment, experience has shown that this is not necessarily the case. Debris has been found entangled on abandoned wellheads during removaloperations and there have been instances of fouling on active subseacompletions. In the majority of the incidents, apart from the inconvenience ofhaving to remove the entangled debris left on the wellhead, the damageinflicted has been of a relatively minor nature. No reports are available ofcatastrophic damage inflicted as the result of such an incident. DATA Data di pubblicazione: 04/04/2013 AUTORI FADEN GEORGE P FENEMORE KEITH E FRASER WILLIAM J ENTE DI AFFERENZA ZENITH CAPE LTD RIVISTA European Offshore Technology Conference and Exhibition, 21-24 October, London, United Kingdom