Recovery from Hydrate Plug During Well Control incident using Coiled Tubing
Abdullah Eshtewi
Completions Engineer
DRIMS # 7594942
Sep 2011
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Agenda
• Overview.
• Themes.
• Where ? Why ?
• Coiled Tubing rig up.
• Hydrate Milling operation.
• Coiled Tubing abrasive cutting and perforation.
• Choke and Kill line blockage.
• Lessons learned.
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Larsen-1 Overview
• Production casing ran and cemented with the 9 5/8” casing shoe set at 2829m.
• On February 1st 2010, drilled into gas bearing formation and a gas kick was recorded at 4602m.
• Well was shut in and the formation 100m below the shoe broke down - under ground blow out.
• Attempts to control the well by setting Barite plugs were unsuccessful.
• Well control operations were complicated by hydrate blockage in the C&K lines and drill pipe.
• The well was P&A on March 18th, 2010, after 38 days to control the well.
This presentation will focus on challenges encountered during Coiled Tubing operations
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Themes
1. Contingency planning.
• Think a head to cater for escalation.
2. Problem solving.
• Require open minded and experienced team to adopt unconventional solutions.
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Where ?
Larsen 1
• Larsen-1 is located on the Exmouth Plateau.
• 1200m water depth.
• Deepest well for woodside in the area.
• New built Semi-Sub “Maersk Discoverer” drilling rig.
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Sequence of Events Prior Intervention
• Took a kick “under ground blow out”.
• Pumped 2 x Barite plug (unsuccessful).
• Blocked C&K.
• Ran in hole E-line to sever pipe, tag shallow at 1165m.
Start Planning Coiled Tubing “NOW”
Better to start planning early
Slide 7/32 4606m
9 5/8” 2829m
6 ¾
” B
HA
5”
DP
5.87
5”
DP
1279.2m BOP Shut in on Annular
Choke Line No Circ
Boo
st L
ine
OK
Riser
E line BOP
5”
HW
DP
Loss zone
2 x FOSV
• Under ground blow out.
• Well shut in.
• Stuck BHA.
• C&K lines plugged.
• DP plugged.
• Trapped pressure below BOP.
Status Schematic
Kill Line No Circ
Gas cross flow
• No Tool access • No circulation path • Pressure build up be low BOP
Rig up Coiled Tubing “NOW”
Pressure build up
below BOP
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Plan of attack
• Rig up Coiled Tubing.
• Mill Hydrate plug.
• Sever the DP, pump barite and cement plug to isolate lower zone.
• Sever the DP and pump cement plug to isolate the shoe.
• Remove trapped gas below BOP.
• Clear C&K lines using CT
4606m
9 5/8” 2829m
6 ¾
”B
HA
5” DP
5.87
5”D
P
Boo
st L
ine
OK
Riser
E line BOP
5” HW
DP
2 x FOSV
Trapped gas
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0.6m
Rigging up Coiled Tubing
• FOSV => 2 ¼” ID, changed out to 2 ¾” ID
• Only few CT tools fits through this restriction
• Drill Pipe elevators Not suitable to rig up CT
E-Line R/U
Upper Tension frame
45’ bails
DP elevator
FOSV
Lesson learned: Up front planning for well control operations
Slide 10/32 1.8m
Rigging up Coiled Tubing
king size elevator
Used D.P elevators as C plate
10cm O ring is required
Up front planning for well control incidents
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Rigging up Coiled Tubing
~25m
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Rigging up Coiled Tubing
• CT hoses did not reach Injector head.
Up front planning
• New built rig.
• CT rig up on computer model.
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Plan of attack
• Rig up Coiled Tubing.
• Mill Hydrate plug.
• Sever the DP, pump barite and cement plug to isolate lower zone.
• Sever the DP and pump cement plug to isolate the shoe.
• Remove trapped gas below BOP.
• Clear C&K lines using CT
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Milling Hydrate - Design
Key component:
• Hydrate suppression mud “HSM”
Mobilized all the MEG on the east cost !
• Mill design
• Motor performance
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Milling Hydrate - Operation
Operations:
• RIH and tagged top of plug at 1156m.
• Displaced to HSM.
• Milled through Multiple layers of Hydrate with pressurized gas pockets in between.
• Continued RIH C.T and drifted the pipe.
• Encountered losses.
• Set a DP plug.
• Multiple hydrate plugs rather than one solid plug • Huge quantities of MEG were required
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Plan of attack
• Rig up Coiled Tubing
• Mill Hydrate plug
• Set PSP plug to stop losses
• Sever the DP, pump barite and cement plug to isolate lower zone.
• Sever the DP and set cement plug on shoe
• Remove trapped gas below BOP.
• Clear C&K lines using CT
Requirment to understand well behaviour and performance of barite/cement plugs
Temperature Log
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20
40
60
80
100
120
140
24002500
26002700
28002900
30003100
32003300
34003500
36003700
38003900
40004100
4200
Depth (m)
Tem
pera
ture
(deg
C)
Drims
Shoe Loss zone
Temperature Log Analysis
Run 1 - PSP plug in the string, T log after ~ 6hrs Run 2 - Sever the DP and pump ~400bbls 1.25sg “dynamic kill: followed by 90 bbls barite plug Run 3 - T log after ~ 8hrs Run 4 - After Cement plug
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20
40
60
80
100
120
140
24002500
26002700
28002900
30003100
32003300
34003500
36003700
38003900
40004100
4200
Depth (m)
Tem
pera
ture
(deg
C)
Drims
Shoe Cut at 4245m
Loss zone
Temperature Log Analysis
Run 1 - PSP plug in the string, T log after ~ 6hrs Run 2 – Sever the DP and pump ~400bbls 1.25sg “dynamic kill: followed by 90 bbls barite plug Run 3 - T log after ~ 8hrs Run 4 - After Cement plug
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20
40
60
80
100
120
140
24002500
26002700
28002900
30003100
32003300
34003500
36003700
38003900
40004100
4200
Depth (m)
Tem
pera
ture
(deg
C)
Drims
Temperature Log Analysis
Shoe Cut at 4245m
Loss zone
Run 1 - PSP plug in the string, T log after ~ 6hrs Run 2 – Sever the DP and pump ~400bbls 1.25sg “dynamic kill: followed by 90 bbls barite plug Run 3 - T log after ~ 8hrs Run 4 - After Cement plug
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20
40
60
80
100
120
140
24002500
26002700
28002900
30003100
32003300
34003500
36003700
38003900
40004100
4200
Depth (m)
Tem
pera
ture
(deg
C)
Drims
Run 1 - PSP plug in the string, T log after ~ 6hrs Run 2 - Sever the DP and pump ~400bbls 1.25sg “dynamic kill: followed by 90 bbls barite plug Run 3 - T log after ~ 8hrs Run 4 - After Cement plug
Shoe Cut at 4245m
Loss zone
Temperature Log Analysis
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Plan of attack
• Rig up Coiled Tubing.
• Mill Hydrate plug.
• Set PSP plug to stop losses.
• Sever the DP, pump barite and cement plug to isolate lower zone.
• Sever the DP and set cement plug to isolate the shoe.
• Sever DP at the shoe to release string.
• Remove trapped gas below BOP.
• Clear C&K lines using CT
Slide 22/32 4606m
9 5/8” 2829m
4565m
4421m
6 ¾
” B
HA
5”
DP
5.87
5”
DP
5”
HW DP
Barite
Cement
E-line tagged obstruction 2631m
Uncertain shoe isolations
4606m
1279.2m BOP Shut in on Annular
Choke Line No Circ
Boo
st L
ine
OK
Riser
E line BOP
2 x FOSV
Kill Line No Circ
Status Schematic
Must regain access Attempted to mill cement Inside the DP using CT
trapped gas
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Plan of attack
• Rig up Coiled Tubing
• Mill Hydrate plug
• Set PSP plug to stop losses
• Sever the DP, pump barite and cement plug to isolate lower zone.
• Sever the DP and set cement plug to isolate the shoe.
• Sever DP at the shoe to release string.
• Mill cement inside DP and sever DP below shoe depth.
• Remove trapped gas below BOP.
• Clear C&K lines using CT
Coiled Tubing abrasive cutter
Risk of casing damage with E-line severance tools + Surface restriction at FOSV
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CT abrasive cutter
100 mesh sand
Slurry filter before the C.T realer Sand suspension test up to 90min
Sand concentration ~ 120 kg/m3 max
New Technology within Woodside.
Main Risks: 1. Eroded coil / surface equipment. 2. Plugged coil / surface equipment.
You want to do what ??!
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Coiled Tubing Abrasive cutter
• BHA
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Operations:
• Position cutting head at desired depth.
• Flush annulus 2 x annulus volume.
• Pumped pre determined slurry volume and successfully cut the DP.
• Flush annulus 2 x annulus volume and POOH.
Encountered issues.
• 2 X Cement unit failed during the pumping operations.
Coiled Tubing Abrasive cutter
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Plan of attack
• Rig up Coiled Tubing
• Mill Hydrate plug
• Set PSP plug to stop losses
• Sever the DP, pump barite and cement plug to isolate lower zone.
• Sever the DP and set cement plug to isolate the shoe.
• Sever DP at the shoe to release string.
• Mill cement inside DP and sever DP below shoe depth.
• Cut DP above the shoe using CT abrasive cutter and cement the shoe.
• Remove Trapped gas below BOP
• Clear C&K lines using CT
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Removing trapped gas below BOP
Operations:
• RIH CT Memory CCL.
• RIH CT abrasive perforate and punch hole.
• Bleed off gas below BOP.
• Strip DP and bleed off remanning gas below annular.
2 x 3/8” holes
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Choke and Kill line Coiled Tubing rig up
Return line
• Nipple down slip joint.
• Pulled out first riser joint and land on riser spider.
• RIH C.T jetting BHA ONLY and cleared up C&K.
Rotary Table
Riser Joint
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Plan of attack
• Rig up Coiled Tubing
• Mill Hydrate plug
• Set PSP plug to stop losses
• Sever the DP, pump barite and cement plug to isolate lower zone.
• Sever the DP and set cement plug to isolate the shoe.
• Sever DP at the shoe to release string.
• Mill cement inside DP and sever DP below shoe depth.
• Cut DP above the shoe using CT abrasive cutter and cement the shoe.
• Remove Trapped gas below BOP
• Memory CCL.
• Run CT abrasive perforator and circulate the gas out.
• Clear C&K lines using CT
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Themes
1. Contingency planning.
• Think a head to cater for escalation.
2. Problem solving.
• Require open minded and experienced team to adopt unconventional solutions.
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My personal take on this effort…
It’s not rocket science, but...
• Time frame very very short due to well control nature, but.
• My first well control experience.
• Variety of technical hurdles.
• Achieved the unachievable with no HSE incidents.
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Questions