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DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 3
Selected wells :
Abandonment Well Review
Cossack-2
Cossack-3
Wanaea-5
Echo-1
Yodel-1
Goodwyn-9
Adequate subsurface barriers in place so that
severance of the wellhead suffices to complete
the abandonment.
No value associated with re-entry for data
acquisition purposes
All wells meet following criteria :
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 4
Equipment overview
The Havila Harmony was mobilised for the North West Shelf Severance campaign out of King Bay Supply Base, Dampier.
The vessel sailed out to location on the 4th June 2008.The AXE severance system has a
proven track record
The operations were delayed on numerous occasions by weather, NPT and many unforseen challenges caused from marine growth and limited well information.
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 5
Severance Timing Charts
NWS Severance Location Breakdown
Echo 1Goodwyn 9Yodel 1Wanaea 5Cossack 2Cossack 3
Cleaning operations
0
5
10
15
20
25
Cleaning ops
Echo 1Goodwyn 9Yodel 1Wanaea 5Cossack 2Cossack 3
Wellhead Cap Removal
0
5
10
15
20
25
30
Locations
Hou
rs
Echo 1Goodwyn 9Yodel 1Wanaea 5Cossack 2Cossack 3
Cutting operations
0
5
10
15
20
25
Severance
Locations
Hour
s
Echo 1Goodwyn 9Yodel 1Wanaea 5Cossack 2Cossack 3
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 6
Cleaning operations
A total of 33.5 hours was spent cleaning marine growth from the wellhead caps and conductor housings in preparation for tooling deployment.
A purpose built ROV cleaning tool was mobilised specifically for cleaning the vent ports on the 30”conductor housing.
Various methods were utilised for blocking the vent ports in the 30” conductor housings, cement was used in the Cameron style and magnetic plugs were trialled on the FMC and Vetco styles. These were subsequently changed out for a more robust hydrostatic style of plug.
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 7
Wellhead Cap Recovery
There were 3 different styles of wellheads and caps, (Vetco, Cameron and FMC). The Cameron style cap in the picture was fitted with shear pins rated to 50,000lbs.
The caps were originally installed using a “J” slot running tool.
The “J” slot running tool was used in conjunction with a bumper sub in an attempt to recover the wellhead caps, load applied to the tool was around 36T, due to marine growth the caps refused to come off using this method.
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 8
Wellhead Cap Removal
Due to the problems encountered with the cap removal a purpose built jacking assembly was manufactured to fit the FMC style caps.
The jacking tool had to be modified whilst offshore to fit the Cameron Style caps.
The jacking tool was successfully deployed and wellhead caps were recovered from all of the wellheads.
The maximum pressure applied to the tool was 1500psi, this equated to a force of 84.6T for the to release.(Well above the figure of 50,00lbs = 22.6T)
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 9
Yodel-1 removed
Plenty of marine life around !
Bigfoot TGB, weighs ~36ton
Yodel well head recovery
Severed casings
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 10
Cost v Budget
Initial mobilisation, transit and demobilisation fees managed within budget
Severance trend shows learning's incurred on first wells
Left chart shows severance cost detail
Downward trend for all activities through completion of campaign
Note 26% weather downtime
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
AFE perwell*
Echo-1 Yodel-1 Goodwyn-9 Wa-5 Ck-2 Ck-3
A$M
Initial mob fee Transit/mob/demob Severance cost
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Echo-1 Yodel-1 Goodwyn-9 Wa-5 Ck-2 Ck-3
A$M
WoW NPT Clean wellheadRemove cap Drift casing Cement/plugCut wellhead Recovery Future recovery
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 11
Current Status
The wellheads at Echo 1, Wanaea 5, Cossack 2 and Cossack 3 have now been severed but require more than 35T to pull the wellheads clear from the sea bed. Unable to complete due to crane control system fault which limited pull to 35t
The wellheads from Yodel 1 and Goodwyn 9 were successfully recovered to surface.
Remaining wellheads now removed using anchor handler to unseat from seabed working in tandem with the Havila Harmony,
“SERPENT” project on board, this study collects, research
information and samples, end result may be non recovery of
wellheads under some circumstances
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 13
Rigless Intervention Capability
What have we done so far -
7 of Subsea trees deployed, installed and tested successfully
7 “shallow” wireline runs to pull hanger plugs successful
4 “deep” runs to pull prong/plug successful (max ~1400 metres)
4 of Formation Isolation Valves cycled open
All wells handed over ready for operation weeks ahead of requirement
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 14
How did we do it - Mobilisation
Significant logistical operation, as can be seen from the before and after photographs there was a large amount of equipment to be installed and sea fastened to the vessel. The large “frame” is the VDS, this in conjunction with a 50 ton heave compensated winch is used to deploy and recover the subsea intervention system through the vessel moonpool.
Around 60 trucks and 2 cranes were used in the mobilisation of all this equipment from Perth and Karratha. None of the equipment had ever been installed on the vessel before and resolving interface issues and providing a safe working area for personnel was a considerable challenge.
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 15
Deployment of Xmas trees
Conventionally an Xmas tree would be run from a drilling rig using rigid riser and a hydraulic umbilical to supply locking and testing capability. This can take a significant amount of time especially in deeper water.
From the Havila Harmony the Xmas tree was run using a simple mechanical tool and the vessel 150ton active heave compensated crane. Locking and testing capability were supplied by the vessel ROV fitted with a specially developed hydraulic power pack and tooling. This method gave a greatly simplified running procedure and the all components of the developed system can be used in water depths up to 2000 metres.
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 16
Well Intervention
Well InterventionOn completion of the Xmas tree installation the vessel intervened on the wells. 12 wireline runs
were completed to a maximum depth of 1400 metres, each successfully pulling a wireline plug, in 4 of the wells a Formation Isolation Valve was also opened.
This intervention was completed using a newly developed WellOps SEA Subsea Intervention system which unlike traditional rig based methodology does not require a riser to extend from the seabed to surface. Instead the pressure control equipment required to intervene on the wells is installed directly on the Subsea tree.
This was technically the most challenging aspect of the campaign, although significant integration testing had been carried out prior to mobilisation none of the components had been used operationally or even been subsea before. The first deployment and successful operation was completed in a water depth of 372 meters.
Subsea intervention device being deployed through moonpool
ROV guiding wireline toolstring into subsea lubricator
Subsea intervention device on top of EVXT during SIT
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 18
Times for Tree installation
10.75 35.75 17 12.5 8 8.75 9.75 7.5
0
5
10
15
20
25
30
35
40
Hours
From surface to test
Xmas tree installation & test
Tech Limit W3 W2 G1 H3 H4 H2 H1
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 19
Times for unplugging the wells
45 175 118.5 86.5 59.25 33.25 32 27.75
0
50
100
150
200
Hours
1Times from surface to surface
Un-plug well / open FIVTech Limit G1 W2 W3 H3 H4 H2 H1
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 20
Rigless Intervention, how did we get there
Full SIT, no time or budget restraint, only stipulation was to get it right, It took 4 weeks & cost >$1M but was worth it. All major NPT issues were as a result of untried/untested items, SIT was dry !Wet trial of Intervention equipment prior to deployment on 1st well.Had several “install tree on paper” sessions with relevant personnel, ultimate solution significantly different and easier than original planDedicated FMC engineer from 4 months before campaign startedOffshore supervision all involved in preparation from at least 3 months prior to mobilisationOffshore supervision, same people from beginning to end.Dedicated HSE coachConsistent WEL project management team, allowed quick decision making.Working with SOG and Vincent project team facilitated “break” in campaign, this allowed numerous system improvements to be made for 2nd campaign.
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 21
Rigless Intervention, achievements so far–
First deployment and installation of Subsea Xmas trees from a vessel in this regionDevelopment of a robust and reliable method of deploying, installing and testing Xmas trees in water depths up to 2000 metres.First subsea well intervention in this region, 4 wireline runs completed with 100% success rate, deepest to 4634ft. First time the WellOps subsea intervention system has been deployedFirst time the Havila Harmony and TS Marine have deployed trees or completed subsea interventionThe unofficial “world record” for subsea wireline intervention is believed to be 377mtr. Woodside have in their first ever subsea intervention achieved 2nd place at 372 mtrs. Project integration, the Havila Harmony also used for project construction and commissioning activities in between well intervention duties. Most importantly the campaign was completed without harm to personnel or the environment. All HSE leading and lagging indicators have significantly exceeded corporate and D&C targets. Only a handful of personnel involved had any experience of this type of operation and it is a considerable achievement to complete it with such an outstanding HSE performance.(subsequent to this had LTI during well severance campaign)
DRIMS #4402418, Author Simon Glennie, DrillWell Sept 08 22
Rigless Intervention Overview
Who did what -
TS Marine – Havila Harmony operator and main contractor, supply of vessel and ROV’s, project engineering and management of sub-contractors. Supply of ROV and supervisory personnel.
WellOps SEA – Subcontractor to TSM, supply of VDS system, subsea intervention system and AXE well severance system. Specialist personnel to operate equipment.
FMC, supplied trees and interface control system. Dedicated engineer & offshore personnel
Schlumberger – Wireline equipment, pumping equipment and bleed off package. Personnel offshore