ELGIN G4 GAS LEAK INCIDENT 25 March – 16 May 2012

ELGIN: KEY FACTS & FIGURES

Operated by Total for 8 x JV partners

Elgin PUQ (Production Utilities Quarters) & wellhead platforms linked by 90m bridge

High Temperature/High Pressure fields

On stream since 2001

Elgin produces 135k boe/d

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012) 2

ELGIN G4: WELL ARCHITECTURE

Seabed @ 93m below platform

Chalk HOD non-producing low permeability high

pressure

Fulmar producing high permeability lower

pressure

On Elgin ‘A’ (wellhead) platform

3 Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

ELGIN G4 GAS LEAK: SEQUENCE OF EVENTS

25 February: sudden decrease of A annulus pressure and rapid increase in B and then C annulus

G4 Task Force established: well intervention program with Rowan Viking rig support

15 March: tubing and A annulus contents displaced to 1.2sg brine

22 - 25 March: well intervention

• start pumping 2.05sg NABM down tubing & up A annulus

• B & C annuli pressure increase

− C annulus bled off through WHP process

− B annulus operating window increased

• after 172m3 operation suspended as mud returns to the process via C annulus

• attempt to re-route C annulus returns line to surge tank

• sudden unsustainable C & B annuli pressure increase - leading to gas release at well head D annulus

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= gas path to surface leak Specialist teams mobilised

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

12.20: gas & condensate leak confirmed at the wellhead on Elgin’s G4 well

13.30: evacuation begins of Elgin and the adjacent Rowan Viking drilling rig

16.40: 219 people have been evacuated, leaving 19 still on the complex

01.45: Elgin OIM decides to fully abandon

Platform, rig & wells shut down

Export pipelines isolated

02.30: the last 19 people are evacuated

All 238 people safely and quickly

evacuated

ELGIN G4 GAS LEAK: DAY ONE (25 MARCH)

5 Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

• Gas, condensate & mud released at deck level

• Visible gas plume formed

• Condensate & mud fall to sea

• Sheen covers a large area of sea surface

• Waxy paraffinic deposits on wellhead platform

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ELGIN G4 GAS LEAK: INITIAL IMPACTS

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

ELGIN G4 GAS LEAK: INITIAL IMPACTS

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7 April surface sheen still

visible, but less than 1/10th micron thick

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

27 March gas plume and sheen visible,

but not obvious

Preferred solution: pumping in heavy mud • a mobile pumping unit putting heavy mud directly into G4 from the wellhead • technically feasible • re-boarding of the Elgin wellhead platform necessary • Wild Well Control already mobilised and suitably experienced • no absolute guarantee of success • timescale measured in weeks

Back-up solution: drilling a relief well • a contingency in the event the well pumping intervention is ineffective • technically feasible • start drilling two wells and use the one that reaches the interception point first • two drilling rigs (Rowan Gorilla V & Sedco 714) to be mobilised rapidly • timescale measured in months

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ELGIN G4 GAS LEAK: SOLUTIONS TO REGAIN WELL CONTROL

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

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ELGIN G4 GAS LEAK: SOLUTIONS TO REGAIN WELL CONTROL

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

ELGIN G4 GAS LEAK: DIVERTER

• Specially designed & manufactured

• Fitted around the leaking G4 well head

• 4 flexible hoses carry gas & condensates away from the well head

• Greatly improved frequency of helicopter flights and access to the wellhead

G4 well head before diverter fitted... ... and after

Two of the diverter’s four flexible hoses

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back

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

29 March: OSRL flights reveal size of sheen has already diminished considerably

30 March: flare is confirmed as extinguished

2 April: pumping in heavy mud & relief well solutions announced

5 April: first re-boarding of Elgin complex by Wild Well Control & Total E&P UK teams

15 April: mobilisation of West Phoenix drilling rig & Skandi Aker as main well intervention support vessels

18 April: Sedco 714 spuds first relief well

26 April: special diverter fitted to G4 well head

The Sedco 714 drilling rig

The diverter on the G4 wellhead

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ELGIN G4 GAS LEAK: POST INCIDENT MILESTONES (1)

Leak rate drops to about 33% of initial rate

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

April/May: ongoing preparatory works • successful removal of waxy deposits • laying of 230m of temporary rigid pipeline (‘chiksan’)

10 May: West Phoenix drilling rig alongside

10/15 May: extensive equipment testing

15 May: well intervention operation begins

Regular cleaning operations on the Elgin well head platform

The West Phoenix; the main well kill support vessel

‘Chiksan’ temporary rigid pipeline

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ELGIN G4 GAS LEAK: POST INCIDENT MILESTONES (2)

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

SCANDI AKER

Elgin G4 gas leak incident, 25 March – 16 May 2012 (June 2012) 13

Elgin G4 gas leak incident, 25 March – 16 May 2012 (June 2012) 14

ELGIN G4 GAS LEAK: WELL INTERVENTION OPERATION

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Rowan Viking

Elgin wellhead platform

Elgin PUQ

West Phoenix

Later following successful operation, the logistics resources deployed

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

Elgin G4 gas leak incident, 25 March – 16 May 2012 (June 2012) 16

Pre-intervention testing, using flexible hose ‘Coflex’ from West Phoenix to Elgin PUQ

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ELGIN G4 GAS LEAK: WELL INTERVENTION SET-UP

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

• Dynamic well kill with 2.05sg mud

• Initially pumped water based mud (WBM)

• Pumped through G4 wellhead into tubing

• 511m3 pumped @ a rate of 10-4bbls/min

• Pumped via Coflex & ‘chiksan’ from West Phoenix

• Pumping for 12 hours

• No diversion: pumped fluids exited to sea

• After 3 days, WBM replaced with NABM (Non Aqueous Based Mud)

= mud path while pumping

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G4 now stable and under observation

ELGIN G4 GAS LEAK: WELL INTERVENTION OPERATION

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

• The well has been ‘killed’ and is filled with oil based mud

• The well & gas leak path are under control

• Progressive re-manning of the Elgin complex & the Rowan Viking is underway

• The West Phoenix was demobilised once the Rowan Viking’s pumps were made available

• As a contingency, drilling of a first relief is progressing

• But a decision taken not to drill a second relief well following the successful well kill

Tubing & all annuli filled with NAB mud Other Elgin/Franklin wells being monitored

ELGIN G4 GAS LEAK: CURRENT STATUS

19 Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)

THANK YOU FOR LISTENING

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… any questions?

Elgin G4 gas leak incident, 25 March – 16 May 2012 (July 2012)