Decommissioning of offshore installations in the .... Ramboll. Decom in operational... ·...
Transcript of Decommissioning of offshore installations in the .... Ramboll. Decom in operational... ·...
Decommissioning of
offshore installations in
the operational phase
Kristian Lund Jepsen
Ramboll Oil & Gas
3SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Reasons for decom at fixed installations
Equipment redundant from day one
Equipment/system process wise outdated
Demolition
Equipment/system technological outdated
Equipment failed / worn-out
Replace with equipment / systems that fits changedprocess conditions
Replace with modernequipment / systems withnew technology
Refurbish / Repair
Replace (1 : 1)
4SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Redundant from day one - example
Gas fired heater – back-upfor turbine WHRU’s
Other examples:
•Mud tanks
•Well kill system
•Runway beams
•Trolleys/chain hoists
5SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Process wise outdated equipment
Increased amount of produced water
Change from HP separation to LP Mode
Change in gas composition / mole weight
Change in gas composition – increase of H2S + CO2
Increased amount of oil/gas
Debottlenecking of complete process train
Debottlenecking of produced water system
Larger pipe dia, larger volume in separators
Re-bundling of centrifugal compressors and larger driver
Change piping matr. class from CS to duplex
6SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Technological outdated equipment - examples
� Pneumatic analog instruments
� F&G Detectors / systems
� Control / ESD Systems
� Control panels for gas compressors
9SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Decommissioned – stay in place
Runway beams aredecommissioned to avoid periodicinspections / tests.
10SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Experiences from ”operational decom”
� Dangerous lifting operations (unknown weight+COG)
� Handling of NORM (NaturalOccuring Radioactive Matr)
� Handling of chemical/oil waste
� No asbestos in insulation(however: Flange Insulationkits, Carbon-Asbestos filledgaskets)
Scale may be barium orstrontium sulphate which is NORM material.
11SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
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)
12SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Backload – Logistics and Handling
Return Goods
/ Supply Boat
Well Service
Company
Equipment
Waste skips
Chemical Tote
Tanks
Backload
Containers /
Baskets
Large scrap
items
To Service company
Not dangerous
waste
Chemicals/oil
waste
Empty - send
to Kommune
Kemi
Empty -
normal
renovation
Waste to Kommune Kemi
Tank Cleaning
Waste to Kommune Kemi
Refill Tote
Tank
Sorting /
Evaluation
To Service /
Repair
company
To be Stocked for
later use
(OIL COMPANY'S
STORE)
To be sold for
re-use
Repair /
scrap
Repaired/
To stock
Supply Goods
/ Supply Boat
Scrap Yard
Scrap
Repaird - directly return to offshore
Costums area
13SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Estimate Model. All Danish offshore fields – installedpiping / 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 15148Scrap/change-
out % yearly 10 5 2,5Scrapped piping
- tons yearly 692 241 85 1018
Totally decommissioned from Danish offshore platforms yearly - estimated tons:
Piping 1000
Mech. Equipm. 500
Structures 250
Elect/Instrum 200
Other 50
Totally 2000
The model is based on a life time of 20 -25 years of an installation.
14SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
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
15SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
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 packagedemolished in Esbjerg Port 2001. Packagetaken over by Hannover Company
•The rig converted back to drilling.
16SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Statoil preparations to decom. HSE / NORM
� Study of consequences (“Konsekvensutredning – Ymeavslutningsplan”).
� 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.
21SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
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
23SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Mobile offshore units. Decom status.
� Yearly 2 units in the harbour.
� Equipment decommissioned/scapped yearly: 500 tons – 2000 tons
24SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
Total status. Decom. Tonnes handled yearly
From fixed installations 2500 - 4000
From mobile offshore units 500 - 2000
Total 3000 - 6000
25SlideOctober 15, 2007Basic Ramboll Oil & Gas PPT
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.