Ice Risk Management for Floating Operations in Pack Ice
Total Page：16
File Type：pdf, Size：1020Kb
Ice Risk Management for Floating Operations in Pack Ice A KAC I NC SNAME, Calgary October 2010 By Arno Keinonen, Evan Martin Whose Ice Risk? What Ice Risk? – Oil company and rig owner/operator responsible 1 Oil Company - Desire to have maximum uptime yet being safe 2 Rig operator – Little desire to take risks 3 Overseeing organizations, regulators, standards – Biggest ice risks – Pioneering • Lack of understanding environment, equipment, operation – and resulting associated risks • Lack of appropriate strategy for safe learning/contingency/layered safety • New operators Reference Operations • Beaufort Sea Drillships, 1975 - 1989 – Ice class drillships with icebreaker support (4 – 5 icebreaking vessels) • Kulluk 1982 - 1993 – Custom designed ice capable floating drillrig, with custom designed icebreakers (2 – 4 icebreakers) • Sakhalin Dynamic Positioning, 1999 – Ice class construction vessel with icebreaker support (2 icebreakers) • Sakhalin 2, phase 1 Oil Production 1999 - 2007 – Bottom founded production platform – Low ice class and capability SALM/FSO with icebreaker support (2 – 5 icebreakers at a time; 15 different icebreakers, ice class vessels) • Arctic Coring Expedition 2004 – Selected stationary vessel with icebreaker support (2 icebreakers) Beaufort Sea Drillships Explorer 4 Kigoriak 3 * Class 2 supply Tug Orion First operation in ice offshore 1975 - 90 In start of winter up to ~0.5 m thick ice Summer time thick ice interfered Learning safely – not in hydrocarbon zone Ice capabilities of vessels and rig not known Ice alert system developed Kulluk Kalvik Icebreakers Terry Fox Kalvik + Icebreaking supply Ikaluk Miscaroo 1982 – 1993 Moored conical DrillRig Custom designed system for ice Capabilities of rig and icebreakers known Learning safely, testing in thick old ice Alert system developed further 1.5 m ice plus ridges Sakhalin Dynamic Positioning CSO Constructor DP operation for diving/under water CSO Constructor construction, 1999 – 6 weeks IB Smit Sakhalin 5 m offset allowed IB Magadan Short t-time – less than 1 hour - Ice Capability of Safe learning- station keeping without divers Constructor was not known Up to 1.7 m ice and stamukhi (rubble bergs) Beaufort Ice alert system adapted Sakhalin 2, phase 1, SALM – FSO Okha 1999 - 2008 early production of oil FSO operation - oil Production Molikpaq Custom designed SALM and FSO for ice Ice capability 30 cm winter ice, ice class D0 1 m thick 50 m floes in spring High risk operation T-time 48 hrs SALM – FSO Ice Risk Management Development of Ice Risk Management Safe learning through layered safety 2 – 5 support icebreakers at a time ( Admiral Makarov, Smit Sakhalin Pacific Enterprice, Svitzer Sakhalin) Arctic Coring Expedition, 89 degrees N Sovetskiy Soyuz Oden One off coring operation 2004 Vidar Viking (coring vessel) 3 weeks Central Polar Pack 50 m offset allowed T-time 0 - 4 hours 2.5 – 3m average ice thickness 7 – 8 tenths old ice thick multi year ridges Ice alert system adapted Photo courtesy Swedish Polar Research Secretariat Operational Ice Risks and Experience Summary of Safety in Pack Ice for Reference Operations • All operations have been safe (no spill, no fatalities, limited ice damage to equipment) • All learning has been done safely • All but one operation had same main/oil operator and rig operator and used an ice alert system • SALM/FSO Oil Production operation different – Operation lowest iceclass (D0), lowest ice capability, highest risk, longest t-time – Oil Company and Rig operator two different companies – Ice Risk Management became a necessity Risk - Extreme Ice Features Stamukhi, within 3 nautical miles from SALM/FSO Risk - Cold Temperature Everything else freezes before the ocean SALM Buoy requires access before laying down Photo courtesy Sakhalin Energy Risk - Ice Compacting/Ice Pressure Low ice pressure: Sovetskiy Soyuz breaking ice around operation Oden attempting to clear ice with propeller wake Limited Visibility Increases Ice Risk Limits available information Accuracy of data declines when dead reckoning Missing managing some ice floes Ice Risk Management – Probability distributions for: • Ice severity (on arrival) • Severity of metocean factors (waves, wind, currents) • Possibility of arrival • Time of arrival • Efficiency of ice management • Severity of interaction • Full range of ice risk (plus probability of exceedence of official limits) Probability distribution for ice arrival Efficiency of Ice Management (IM) – Probability distributions, influence on efficiency for: • Strategy, what ice to manage, when, where and how (pre- management, traditional ice man., azimuth ice man.) • Skill and experience of operators • Human errors (judgment, fatique, failure to execute instruction) • Visibility and other metocean factors • Equipment failure • Ship collision – Outcome: – IM efficiency factor - floe size distribution/ice clearing efficiency – probability of ice load on platform Main Ingredients for Safe, Efficient Pioneering Floating Ice Offshore Operation – Understanding the ice and environment – Understanding the equipment and operation – Using Ice Alerts, Ice Risk Management for long t-time – Using layered safety – Assigning roles and responsibilities clearly – Establish safe learning procedures – Using experienced operators – Building in training AKAC INC. AKAC INC. # 311 – 877 Goldstream Ave. NRC – IOT Building, Arctic Avenue Victoria, B.C. Canada V9B 2X8 P.O. Box 12093, St. John’s, NL A1B 3T5 Tel. 1-250-477-3887 Fax. 1-250-477-3892 Tel. 1-709-772-2464 Fax. 1-709-772-2462 Email: [email protected] Email: [email protected].