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Shelterstone Discovery

P.2370 ~ Block 16/3e

‘Appraisal / Development Options’

ENVOI Limited

26th May 2021Post-CA: Vrn 2.2

Shelterstone

Discovery

Enneco Ltd100% & Operator - Appraisal, Testing & Development

Overview• 16/3a-E22, E22z and E16 wells, drilled to appraise U. Jurassic Brae sands,

define Lwr Cretaceous ‘Skiff Sst’ containing gas and oil

• 3D seismic defines stratigraphic graben margin trap with undrilled 300m updip crestal closure where improved sands are prognosed coincident with sediment entry point off East Shetland Platform

• 16/3a-E22z well defines 40ft (12m) Skiff Sst with 42% N/G, Avg. 15% ø

• Flowed 509 bbls + 9.7 mmscf on short test

• 16/3a-E16 Brae well defines 118ft (36m) Skiff Sst, 62% N/G, Avg. 20% ø + OWC defined as transition zone downdip from 16/3a-E22 wells

UKCS Offshore – Viking GrabenP.2370 (Block 16/3e) Shelterstone Discovery

Shelterstone

Closure

Brae East

Field

Block

16/3e

East Brae FieldShelterstone

Closure

Block 16/3e

16/3a-22z Defined

gas/oil column which

flowed gas/oil at distal

end of Lwr Cret Closure

Shelterstone

‘Skiff Sst’

Brae Reservoirs

Cairngorm

‘basement’

discovery

Prospectivity: 3D mapping defines ‘Most Likely’ Shelterstone resource potential = 115 MMboer (P50) & 163 MMboer ‘Mean’ but could be 300+ MMboer if reservoir thickens as mapped with equivalent reservoir potential, similar to wells in the area including 16/3d-13.

Obligations & Work Programme: Commit to drill one appraisal well

Terms: Earn material share of equity in return for funding wells (Est. US$ 12 mm sidetrack appraisal/producer and US$ 23 mm crestal appraisal well)2

16/3d-13

Quality Skiff

Sst + Shows

Shelterstone Prospectivity

16/3a-E22z

(flowed on test

1997)

Revised ‘Most Likely’

Shelterstone TWT

Closure (115 MMboe)

Previous

Mapped Outline

Top Skiff Closure Mapping 3D (TWT)

16/3d-13

Quality Skiff Sst

16/3a-E16

Quality Skiff Sst

16/3a-E22

16/3a-4

16/3a-22z

(Skiff flowed

on test 1997) East Brae

Field

(U Jurassic)

East Brae

Field (U. Jurassic)

Improved Updip

Closure where sand

expected to be

better than16/3d-13

16/3d-13

16/3d-13

Gross 418 ft Sst (shows

+ Avg 18% ø & 50mD)

Revised P10 ‘Upside’

Shelterstone TWT

Closure (300+ MMboe)

Proposed

Sidetrack

A

A’

B’

B

3

450ft

Brae Sst wet

where

penetrated

E916/3a-4 E22E16E22Z

Proposed New

Well

Updip Well

Potential

East Brae Development, Well 16/03a-E22Z

Skiff Reservoir

• The well encountered 12m gross

interval (5m of net pay) with an

average porosity of 17%

• Oil Saturation averages 70% in the

two main sands

ODT : -3,939mTVDSS

Well Flow tested 19th July 1997 and reported to DECC at the time. Reports

available from the OGA online portal show:

• Completion string was run + 60ft (18m) MD interval perforated prior to testing.

• Well produced for 1.54 days (37 hours) then shut in having produced a total of 81 Sm3 (~ 509

bbls) oil + 276,000 Sm3 (~9.7 mmscf) gas. Why only 37 hours?

• A gradient run showed Shut-In Tubing Hanger Pressure (SITHP) of 870 psi (60 bar) with oil

within the top 8,000ft of tubing and water below. Suggests water influx may have killed the well.

• Samples of oil from the test string indicates a gravity of 47.5 - 48.4° API.

• Tried to produce for additional 3.39 days (81.4 hours) in August 1997 but with no flow.

16/3a-22z Defined

gas/oil column which

flowed gas/oil at distal

end of Lwr Cret

Closure

4

E22Z – Well Test Water Breakthrough

Jurassic Brae Sst

Water Wet

Cretaceous Skiff Sst Oil & Gas Pay

E22Z

Deviated Well Bore

7,300 psi water pressure in wet Brae Sands

where penetrated with high pressure water

believed to have leaked up behind pipe to

perforations over Skiff Sands

Cement Bond inferred as poorly bond

below Skiff (where not logged but likely

to be similar to the poor bond logged

above Skiff).

East Brae

Gas Field

Oil & Gas pay in Skiff Sst

at 6,100 psi pressure so

less that water in Brae Sst

Water preferentially produced

due to higher pressure in deeper

wet Brae Sands

CBL above Skiff shows poor

bond behind pipe so likely to be

the same below

5

Appraisal / Development Options

• This location is approximately 60m higher than E22Z. Gross thickness 45m c.f. 16/3a-E16 with 36m gross

• Estimated to have an initial flow rate of 9mmcfd and 500 bcpd which could produce 13 Bcf and 1 MMbo

over 5 years

• Once production is established the whole Shelterstone structure is de-risked with reservoir distribution the

only uncertainty

Proposed

Sidetrack

X X’

X

X’

Skiff Sst Thickens

East Brae

Gas Field

East Brae

Gas Field

Crestal

Appraisal Well

6

16/3a-E22z

(flowed on test

1997)

Proposed Sidetrack

Location where Skiff

Reservoir Thickens

+

?

+

3-4 Follow on

locations

+

?

16/3a-22z Skiff Bottom

Hole & Location

of flow testSkiff

Reservoir

Improvement

Revised ‘Most

Likely’

Shelterstone

TWT Closure

(115 MMboe)

+

East Brae Development Potential

Top Skiff Time Map (Blue lines = 1 km grid)

16/3a-22z Skiff Bottom Hole &

Location of flow test

East Brae

PlatformProposed Sidetrack

Location where Skiff

Reservoir Thickens

3-4 Follow on

Locations

Skiff Reservoir

Thickens &

expected to

improve

Approx 4km circle from East Brae platform. All purple are closer than E22Z Well. Orange location is less certain. 4 wells could produce

57bcf and 4mmbo over 10 years, extending the life of East Brae

Shelterstone Appraisal/Development Options

1. Using East Brae Platform, deferring COP

Total NPV10 US$827million

• Drill sidetrack of E22z well and three further wells from East Brae Platform

(South Shelterstone)

• Drill Crestal Appraisal Well at North Shelterstone

• North Shelterstone Field Subsea Development via East Brae

2. East Brae with COP 2023

Total NPV10 US$491million

• Drill sidetrack of E22Z well from East Brae Platform

• Drill Crestal Appraisal Well at North Shelterstone

• Utilise Stand alone platform/FPSO to develop North & South Shelterstone

Field

3. No use of East Brae

Total NPV10 US$491million

• Drill Crestal Appraisal Well at North Shelterstone

• Utilise Stand alone platform/FPSO to develop North & South Shelterstone

Field

Proposed Sidetrack

Location where Skiff

Reservoir Thickens

Crestal Appraisal Well

~ 200m up-dip from E22 well

8

Commercial / Opportunity

• The ability to use the East Brae platform has the

potential to nearly double the value of the project and

is in line with the MERUK strategy

• East Brae will be able to derive additional value from

reduced opex, additional late life production and

deferred decommissioning costs

• Reduced emissions intensity and EUETS costs (carbon

trading)

• Potential for further East Brae infield development

• Opportunity for emission reduction projects,

electrification etc

Farm out way forwards

• Marketing with Envoi and offering

• Earn a material interest in return for

• Funding appraisal wells (Est. US$ 12 million sidetrack

appraisal producer from East Brae with US$ 23 million

crestal appraisal well)

9

Shelterstone

Disclaimer: The information in this presentation is for guidance only. Neither Envoi Limited (Envoi), its associates (‘Associates’) nor any director,

officer or employee of Envoi and its Associates accepts responsibility for or makes any representation or warranty, express or implied, with respect

to the accuracy or completeness of the information, estimates and opinions contained in this document.

Office : Old Stables House

(Registered Office) 1d Manor Road

West Ealing

London, W13 0LH

United Kingdom

Phone : +44 (0)20 8566 1310

E Mail : deliver@envoi.co.uk

Website : www.envoi.co.uk

Contact : Mike Lakin (Managing Director)

For Additional Information

10

Office : 18 North Silver Street

(Registered Office) Aberdeen

AB10 1JU

Scotland

Phone : +44 (0)7711 588 970

E Mail : info@enneco.co.uk

Website : www.enneco.co.uk

Contact : Henry Duncan (Director)