Decommissioning of offshore installations in the operational phase
Kristian Lund Jepsen Ramboll Oil & Gas
Two types of installations – two types decom
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 2
Reasons for decom at fixed installations Equipment redundant from day one
Demolition
Equipment/system process wise outdated
Replace with equipment / systems that fits changed process conditions
Equipment/system technological outdated
Replace with modern equipment / systems with new technology
Equipment failed / worn-out
Refurbish / Repair
Basic Ramboll Oil & Gas PPT
Replace (1 : 1) October 15, 2007
Slide 3
Redundant from day one - example Other examples: •Mud tanks •Well kill system •Runway beams •Trolleys/chain hoists
Gas fired heater – back-up for turbine WHRU’s
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 4
Process wise outdated equipment Increased amount of oil/gas
Debottlenecking of complete process train
Increased amount of produced water
Debottlenecking of produced water system
Change from HP separation to LP Mode
Larger pipe dia, larger volume in separators
Change in gas composition / mole weight
Re-bundling of centrifugal compressors and larger driver
Change in gas composition – increase of H2S + CO2
Change piping matr. class from CS to duplex
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 5
Technological outdated equipment - examples Pneumatic analog instruments F&G Detectors / systems Control / ESD Systems Control panels for gas compressors
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 6
Examples – worn-out equipment
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 7
Heat exchangers for cleaning/refurbisment
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 8
Decommissioned – stay in place Runway beams are decommissioned to avoid periodic inspections / tests.
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 9
Experiences from ”operational decom” Dangerous lifting operations (unknown weight+COG) Handling of NORM (Natural Occuring Radioactive Matr) Handling of chemical/oil waste No asbestos in insulation (however: Flange Insulation kits, Carbon-Asbestos filled gaskets)
Basic Ramboll Oil & Gas PPT
Scale may be barium or strontium sulphate which is NORM material. October 15, 2007
Slide 10
Estimates – tons metal scrap per year Detailed data from one platform – backload to shore during one year. Assumed a model partly based on above data from one platform for calculating the amount of equipment “operational decommissioned” yearly. Assessed the Customs Authorities to obtain information about “import from offshore installations”. Assessed the oil Companies (DUC/Mærsk Oil, Hess, DONG E&P)
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 11
Backload – Logistics and Handling Well Service Company Equipment
To Service company
Not dangerous waste
Empty normal renovation
Chemicals/oil waste
Empty - send to Kommune Kemi
Waste skips Return Goods / Supply Boat Chemical Tote Tanks
Waste to Kommune Kemi
Waste to Kommune Kemi Tank Cleaning Refill Tote Tank
Backload Containers / Baskets
Costums area To be sold for re-use
Sorting / Evaluation Large scrap items To be Stocked for later use (OIL COMPANY'S STORE)
Repaired/ To stock
To Service / Repair company
Scrap Yard Supply Goods / Supply Boat
Scrap
Repair / scrap
Repaird - directly return to offshore
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 12
Estimate Model. All Danish offshore fields – installed piping / decomissioned piping and totally decommissioned Estimated piping (incl. valves) from Danish offshore platforms decommissioned yearly Installation year 1987 and before 1987 - 1997 1997 - 2007 Totally Age 20 years and more 10 - 20 years 0 - 10 years Piping (tons) 6923 4825 3400 15148 Scrap/changeout % yearly 10 5 2,5 Scrapped piping - tons yearly 692 241 85 1018
Totally decommissioned from Danish offshore platforms yearly - estimated tons: Piping 1000 Mech. Equipm. 500 The model is based Structures 250 on a life time of 20 Elect/Instrum 200 Other 50 25 years of an Totally 2000
installation.
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 13
Estimates from the 3 operators in Danish sector DUC/Mærsk Oil Hess Denmark Aps DONG E&P
Totally: 3100 tons – 3400 tons yearly Variations: 2500 – 4000 tons yearly
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 14
Jack-up rig conversion / decom Maersk Giant: •Converted to oil/gas production 1996. •Production package owned by Schlumberger. •Produced on Yme Field 1996 – 2001, operated by Maersk Contractors. •Decommissioned production package demolished in Esbjerg Port 2001. Package taken over by Hannover Company •The rig converted back to drilling.
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 15
Statoil preparations to decom. HSE / NORM Study of consequences (“Konsekvensutredning – Yme avslutningsplan”). Included evaluations regarding HSE impacts. Included evaluations regarding NORM – it was concluded there was no NORM as seawater had only been injected for a short period in the initial stage of the project. Samples of scale in the production equipment was taken. Concluded that scale was not radioactive and that it was calciumcarbonate.
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 16
Maersk Giant – towing in 2001
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October 15, 2007
Slide 17
Maersk Giant at the port side
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 18
Maersk Giant – production package onboard
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 19
Maersk Giant – equipment being lifted off
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 20
Maersk Giant – 2001 Decom/Conversion Noise / Fire Walls around package removed Flare tower removed Production package removed from deck All interconnecting piping and cabling removed Totally: 1200 tons removed Production package, 800 tons, sold from Schlumberger to Hannover Company – for possible re-use
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 21
Yme production package. Summer 2007
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 22
Mobile offshore units. Decom status. Yearly 2 units in the harbour. Equipment decommissioned/scapped yearly: 500 tons – 2000 tons
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 23
Total status. Decom. Tonnes handled yearly From fixed installations From mobile offshore units Total
2500 - 4000 500 - 2000 3000 - 6000
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 24
Conclusion The amount (tonnes) of equipment decomissioned/scraped and then handled in the harbour of Esbjerg yearly corresponds to the weight of one medium size topside. The experience exists and the companies to handle the waste and scrap are used to handle these items. Large heavy lift cranes (Thialf) cannot go into the harbour. Need for companies who can handle and clean scrapped piping and equipment for NORM. Need for long-term storage facilities for NORM.
Basic Ramboll Oil & Gas PPT
October 15, 2007
Slide 25
