VEGA WELL GROWTH / TEMPLATE SETTLEMENT

WIF SEMINAR, CLARION AIR, 13. JUNE 2019ESPEN SVANEVIK

THE JOURNEYVEGA WELL GROWTH / TEMPLATE SETTLEMENT

1. The Vega field

2. Inspection & integrity

3. 2017 Annual Inspection

4. Survey observations

5. Task Force – Key Activities

6. Lesson Learned

THE JOURNEY , ESPEN SVANEVIK, 13 JUNE 2019 PAGE 2

THE VEGA FIELD

THE VEGA FIELD, ESPEN SVANEVIK, 13 JUNE 2019 PAGE 3

o Developed by Hydro as a tie-back to Gjøa semi-submersible

o Commissioned in December 2010

o Wintershall Operator from March 2015

o Gas Condensate field consisting of:o Three 4-slot integrated template structures

o Dual diameter carbon steel production flowline and 3” MEG injection flowline, extending 52 km from Vega South to Gjøa, via Vega Central & North.

o Dynamic & Static control Umbilical

o 3 new wells planned via the ongoing; Vega infill project

INSPECTION & INTEGRITY

INSPECTION & INTEGRITY, ESPEN SVANEVIK, 13 JUNE 2019 PAGE 4

• Historic inspection program activities

• Annual template and production pipeline survey

• 6 monthly inspection of scour around R-12 (Vega South)

• Focus on Rigid Lock Seal Assembly (wellhead fatigue)

• Pipeline lateral buckling flagged as a main integrity threat

• Risk Assessment & Integrity Management Planning performed in 2016

• Conductor lock ring strength capacity towards well growth, confirmed

• Inspection program updated, to included:• Well growth inspection – max. 75 mm • Bull’s eye inspection – in position

Video of Vega South 2017 annual inspection

Historic scour well R-12, Vega South

Exessive lateral movement of production flowline, South - Central

Rigid Lock Seal Assembly:White ring visible when engaged.

2017 ANNUAL INSPECTION

INSPECTION & INTEGRITY, ESPEN SVANEVIK, 13 JUNE 2019 PAGE 5

SURVEY OBSERVATIONS – VIDEO STILLSVEGA WELL GROWTH / TEMPLATE SETTLEMENT

Video commentary: “inclination to the south with Bull’s Eye sitting on the second ring”. What does this imply?

o 1°, this equals the levelling limit from the installation resume

Note: acceptance criteria not defined in the inspection program

SURVEY OBSERVATIONS – VIDEO STILLS, ESPEN SVANEVIK, 13 JUNE 2019PAGE 6

Video commentary: “the hub connection point appear to be in good visual condition, no obvious evidence of any damage or any cause for concern. What do we see?

o conductor lock ring sleeve, is not visible

o TMGB centre ring retainer, is sheared off

o Conductor housing is visible

“well growth / template settlement” > 200 mm ≫ 75 mm

Wellhead System Assembly; it was not a hub connection!

• Do the CSWIP Online Inspector possess the needed knowledge?

IMR 2013

TASK FORCE – KEY ACTIVITIES

TASK FORCE – KEY ACTIVITIES, ESPEN SVANEVIK, 13 JUNE 2019 PAGE 7

• Phase I – Act & Define

• Containment threat; need for shutdown?

• What is the weak link?

• Well growth / template settlement:

• Is the thermal expansion estimate completely off target?

• inadequate foundation design? Possibility for subsidence?

• How to identify, inspect and do measurements?

• Vulnerability

• can other wells or templates be affected?

• what about connectors and flowlines?

• Review Design-Fabrication-Installation documentation

Questions outnumber the Answers; TENFOLD

Rigid Lock Seal Assembly:White ring visible when engaged.

TASK FORCE – KEY ACTIVITIES

TASK FORCE – KEY ACTIVITIES, ESPEN SVANEVIK, 13 JUNE 2019 PAGE 8

• Phase II – Root Cause

• STEP (sequence-time-event-plot)

• Mapping of Maintenance, Operation and D&W history, in a design-fabrication-installation review framing

• Corrective Actions - short term follow-up of vulnerability • update of inspection activities & intervals• Pipe stress re-analysis

• Vega infill project & D&W interfaces

• Recommendations – long term, life of field perspective• Capital spare – redesign of Choke Module (hub extension)• Wellhead fatigue re-assessment• Independent verification

Rigid Lock Seal Assembly:White ring visible when engaged.

Well Growth Indicator Installed

Job description: Date:

R-12Pressure: bar °C

Flowrate: m3/hour days/hours

WGI meassurement: mm

R-14Pressure: bar °C

Flowrate: m3/hour days/hours

WGI meassurement: mm

Bull's Eye Angle: Direction:

Inspect and read of well growth indicatior (WGI) value. Any change from 300mm or WD provided acceptance criteria is to be reported via first hand report. Baseline: Well in production 0.5 MSm 3 /d. Readable picture to be inserted below:

- insert picture here -

ITS inclination 0,95 ° towards south-east (236 °)

- insert picture here -

Temperature:In case of shut-in well, days shut in:

The following information shall be provided via Vessel Representative and recorded:

The following information shall be provided via Vessel Representative and recorded:

Temperature:In case of shut-in well, days shut in:

Inspect and read of well growth indicatior (WGI) value. Any change from 300mm or WD provided acceptance criteria is to be reported via first hand report. Baseline: Cold Well. Readable picture to be inserted below:

- insert picture here -

First hand reporting on well growth indicator readings and bull’s eye during IMR (ROV) campaigns Updated inspection guidance pictures

Daily Drilling Report extracts (28.07.2009):

• after cementing, template inclination changed 0,5°, from 0,25 to 0,75

• after cement job a crater (washout) was observed around tailpipe on slot R-14 (possibly created by the flushing of tailpipe annulus)

5 m

LESSON LEARNED

LESSON LEARNEDOperational history and historic inspection reports was part of risk assessment & integrity manamgent planning performed in 2016. Has the threat really been captured and adequately detailed?

IMR 2017

IMR Contractor in 2017 reported the «hub connection» to be fine!

The failure of the Conductor Lock Ring Assembly was discovered somewhat coincidental triggered by the bull’s eye inclination after 2017 survey evaluation!

IMR 2014IMR 2013

IMR 2015 IMR 2016

Excessive movement between the well and the template has been photographed yearly without anomaly reporting from 2013 thru 2016

How could a 5 meter deep sink hole next to the foundation of the structure not reach the well handover report?

It was in the daily reports! Did no one think it could be of intererst to the SPS project team, or operational group?

How come did not the SPS Contractor react!

5 m

LESSON LEARNED

LESSON LEARNED

QUESTIONS?