draugen well integrity improvement project · campaign conclusions (1) successful temporary repair...

Copyright of Norske Shell 16/25/2013

DRAUGEN WELL INTEGRITY

IMPROVEMENT PROJECT

WIF Well Integrity Workshop

Residence Hotel, Sandnes

4th June 2013

Ksenia Arkhipova and Jan Sæby

Production Technologists

AS Norske Shell

Copyright of Norske Shell

AGENDA

Draugen History and Field

Overview

Lifetime Extension Challenges

Well Integrity Issues with Ageing

Well Stock

Review of Platform X-mas Tree

Change Out and WI Improvement

Campaign

Conclusions


D3H

E3H

D3H

E3H

DRAUGEN FIELD OVERVIEW

A/S Norske Shell (44.56%)

Chevron Norge AS (7.56%)

Petoro AS (47.88%)

PL 255 in Block 6407/9Discovered 1984 w/development start 1993Haltenbanken basin, 250 m water depth, 1640 mssLow relief N-S trending anticlinal structure, 20 x 6 kmVery good reservoir properties, 28-32% por, 5+ Darcy

Fluid: Light undersaturated oil Artificial lift: gas liftDrive mechanism: weak aquifer drivePressure support: water flood (sea water, PWRI from 2013 onwards)Expected RF 73%

Wells:14 producers, 6 platform, 8 subsea5 water injectors on 2 templates (SWIT, NWIT)1 gas injector – suspended4 infill wells planned, 3 P&A’s planned

Current Production 5800 Sm3/dAverage water cut: 83%


PRODUCTION HISTORY & KEY EVENTS

FIRST OIL ON DRAUGEN

October 19th 1993

October 1994 – Water injection in the north and south came on line with 5 injectors

July 2000 – Highest production reached with 39,978 sm3/day

End 2000 – 8 Producing wells on Draugen

Year 2002 – Subsea development of Garn West and Rogn South

Mid 2002 – Plateau production period is over, significant

increase in water break through

Mid 2005 – Water injection in NWIT is suspended due to ruptured flowline.

Rupture is fixed however NWIT remains suspended.

Year 2008 – Two new wells are drilled (D3 and E3).

December 2011 – FID on Draugen Infill 4 new wells to

be drilled.

Draugen Production Forecast

Changing Operating Conditions:

Tail end oil production, < 5000 m3/d

Significant water production, 25-45,000 m3/d

Increasing H2S levels

Seawater injection replaced by PWRI

Ageing Facilities

Lifetime Extension Challenges

Initial field life expectation – 20 years, i.e. 1993 to +/- 2013.

Current license end – 2024, Production expected to last until 2035

Ageing Wells and Facilities

Challenge to maintain well and asset integrity

Obsolete Ingram Cactus 5k X-mas trees

No ASV installed

Increasing number of Well Integrity failures and long lead times for repair

No drilling/workover capability on platform

End of field life P&A strategy for platform wells, continued monitoring required for

watered out wells

Opex Containment


KEY WELL INTEGRITY ISSUES

Platform wells:

Corroded valve seats in platform X-mas trees

Leaking wellhead seals due to introduction of gas lift => pressure in cavities, A to B ann. communication

DHSV and control line problems

Damaged spindle on B- and C-annulus valves on patform wells

Unknown tubing corrosion status

Subsea wells:

Tree valve operabilities

Hydrates in leaking XOV’s

Well Integrity Testing requirements:

WIT 6 monthly

SIT every 2 years


WELL INTEGRITY ISSUE 1 – PLATFORM WELL A6

Conclusion: Breach of secondary barrier (tubing hanger). Well not in compliance with Norsok D-010 nor Shell Well Integrity Policy.

Draugen A6 – gas lifted platform well

Gas Lift introduced in 2002

Well closed in February 2008 due to external leak through test plug on XT

Investigation concludes with a gas leak through tubing hanger packoff (JS-seal) caused by the A-annulus lift gas (high pressure)

Copyright of INSERT COMPANY NAME HERE

LEAK PATH IN TUBING HANGER

JS-seal cav.

TP5

VoidTP2

Check valve

Test port plug

Bleed port plug

JS-seal assembly

JS-seal assembly

Neck sealTubing

Annulus A

Contained system

External environment

Bleed line Test

line

Leak path: Injection gas passing the JS seals, then entering the void and displacing the void fluid, which in turn leaked through a failed check valve and the improperly torqued plug.


TEMPORARY MITIGATING MEASURES

Classify the tubing hanger as a weakened well

barrier (leak rate less than ALR (0.5%))

Replaced and qualified the plugs and check valves

on test- and bleed ports as additional barriers for

containing void pressure

Established compensating surveillance measures Daily visual inspection

Plug movement

Seeping fluid

Foam leak test on plugs Monthly, 3 monthly, 6 monthly

Get approval from TA’s, notified PSA (Ptil) Continue production under deviation (with 6-

monthly Technical Reviews and Risk Assessments)

while reviewing more permanent repair options


A6 EXT. LEAK REPAIR ACTIONS

External leak fixed and pressure from void contained by pressure tested test- and bleed

plugs

Plugs gas rated to 5.000 psi and Pressure tested

Tubing Hanger Neck seal tested OK.

Repair tubing hanger packoff (JS-seal) by injecting chemical sealant (GlyFlo by Seal-Tite). Finally test and qualify/disqualify the tubing hanger packoff performance.

Seal repair job was not successful

Tubing hanger voids still charged with pressure

Later the leak developed into A to B- communication, again loss of secondary barrier

Continue investigate for a long-term solution Workover?

Chemical sealant?

Alternative design?


WELL INTEGRITY ISSUE 2 – PLATFORM WELL A1

126/25/2013

Draugen A1 – gas lifted platform well

2010 events:

HP hydraulic oil leak from failed WRSSSV

During change out, identified UMV leaking (failed WIT test)

Replaced UMV seals – leak worsened; observed ‘pitting’ on sealing faces of

valve seat

Planned temporary fix by online milling of X-mas tree UMV seat


MILLING OPERATIONS PLANNING

13

NCA – Norse Cutting & Abandonment

Equipment: Lineboring Machine (60 rpm), Zone II ratedHyd Power Unit (15 kW)

• Initial onshore tests

required LMV opened, this

was rejected in HAZID

and required further trials

with closed LMV!


MILLING OPERATIONS

14

• Successful operation

• no accidents or incidents

• 3mm milled

• over-sized seal installed

• restored integrity to UMV in 5

days (including Wireline plug

recovery)


EXPERIENCE FROM NCS

Statoil and other operators have considerable experience with similar problems

Leaking JS-seals

Leaking neck-seals

Leaking ring and radial gaskets

Occurs typically within 2-3 years after the wells have been put on gaslift

Old and often Obsolete designs

Seals not optimized, designed and properly tested for long term gas integrity

Test procedures and criterias

Seal design

Material selection (elastomer/rubber)


DRAUGEN WELL INTEGRITY IMPROVEMENT PROJECT

• The lifetime on Draugen was extended with +/- 20 years, there were

increasing H2S levels and WI issues => improved WI was required

• Based on A1 findings (damaged tree valve seats), it was advisable to

changeout 4 out of 6 platform wells Xmas trees with upgraded specs

(Inconel valve seats) over the forthcoming years – wells had been in

production for 20 years.

• The X-mas change outs would also allow to address the JS seal

problems and the other WI issues (leaking annulus valves, control line

leaks)

• Xmas trees purchased from Cameron (40 week lead time)

• Identical interfaces to existing trees (like for like replacement) but upgraded seats


A1, A6 AND A3 X-MAS TREE CHANGE OUT OPERATIONS

Tree preparation for retrieval,

removed speed lock clamp in

preparation for tree lift

176/25/2013

Old tree lifted out of location

Unable to remove old Xmas

tree with pull of 6500 kg by an

overhead crane. Had to utilise

the lifting jacks (550 Kgs) to

‘break the seal’ or used

pressure in the tubing hanger

cavity to assist breaking

The new Xmas trees were landed and secured in correct orientation first time!

Challenges with removing the Tubing Hanger

Flange Seal

Constructed a fit-for-purpose tool used to remove

flange (only ¼ turn was tight, then by hand)Wellhead, old gasket, metal-to-metal seals – all was found in the good condition


SUMMARY OF DRAUGEN WI IMPROVEMENTCAMPAIGN

186/25/2013

Well no. WI issue Mitigation/Temporary repair Permanent Repair CommentsA1 Pitting corrosion in UMGV, failed leak test Onsite milling New X-mas tree installed

A to B annulus communication Treatment w/Brinker Plasma Re-application of Brinker every 2 yearsLeaking WRSSSV, high hydraulic fluid usage Produced under deviation Replaced WRSSSV WRSSSV held up in X-mas tree during change outLeaking C-annulus valve Replaced valveNon Qualified GLV as barrier element Installed PTC GLVPossible Tubing Corrosion Ran caliper survey Survey indicated tubing in good condition

A2 Leaking Swab valve, not passing WIT test Change out valve seals X-mas tree change outRemaining well w/obsolete X-mas tree Produce under deviation X-mas tree change out X-mas tree repalcement planned Q4 2013

Accidental leak to environment in Apr'13A3 Leaking Tubing hanger seals Treatment w/Brinker Plasma Re-application of Brinker every 2 years

Leaking JS seals, A to B annulus comm. Treatment w/Brinker Plasma Re-application of Brinker every 2 yearsDamaged spindle in B-ann. valve Produced under deviation Replaced valve

A6 Leaking tree cavity test plug Frequent inspection routines Changed out Test Plugs Leak to environment in 2008Leaking JS-seals, A to B annulus comm. Treatment w/Brinker Plasma Re-application of Brinker every 2 yearsDamaged spindle in C-ann. Valve Produced under deviation Replaced valveLeak into DHSV control line Possibly install WRSSSV

Campaign Conclusions (1)

Successful Temporary repair by onsite milling of UMGV seat (3 mm) allowed continued

production until new trees were available

Successful Change out of X-mas trees on A1 (May 2012), A6 (Feb 2013) and A3 (Mar

2013), campaign for each well taking 30 to 40 days.

Successful Change out of C-annulus (A1, A6) and B-annulus (A3) Side Outlet Valves.

Successful repair of JS seals with Brinker Plasma (additional treatments every 2 years),

all wellhead voids treated

Change out of GLV’s as part of primary barrier, old in relatively good condition

Completed multi-finger caliper survey in A1 – tubing in good condition with no significant

penetrations, areas of cross-sectional wall loss or ID restrictions

Change out of failed DHSV in A1

3 Well Integrity issues resoved with each X-mas tree change out, no need for deviations!

Campaign Conclusions (2)

Significant learnings in campaign operation

Problems with change out of Engineering

contractor between jobs

Interfaces between departments (Ops-Eng-

CWI-DE) are a real challenge

A2 X-mas tree change out still outstanding,

planned for Q4 2013

Upon Completion of the WI improvement

campaign, the Draugen platform wells will

have renewed WI to face continued

production for next 20 years.

Thank You !

Any Questions?

draugen well integrity improvement project · campaign conclusions (1) successful temporary repair...

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