Tune Case (NH)Experience from Clean-up and Production using formate based brines as drilling/completion fluids

Tune Case (NH)Experience from Clean-up and Production using formate based brines as drilling/completion fluids

Drilling & Completion Fluid Seminar, Aberdeen 03.06.24By Stine Bøhle Karlsen, Production Technology Tune

Drilling & Completion Fluid Seminar, Aberdeen 03.06.24By Stine Bøhle Karlsen, Production Technology Tune

Agenda – 03.06.24

Tune Field Information

Initial clean-up / Normal Production Tune

3500

PPP

478000 479000 480000 481000

6701000

6702000

6703000

6704000

6705000

6706000

0 500 1000m

30/8-A-14 H

30/8-A-12 H30/8-A

-13 H/A

H

30/8-3

30/8-1S

30/8-A-1

1 H

PPP

475000 480000 485000

6695000

6700000

6705000

6710000

3850- 39003800- 38503750- 38003700- 37503650- 37003600- 36503550- 36003500- 35503450- 35003400- 34503350- 34003300- 33503250- 33003200- 3250

0 2000 4000m

30/8-A-12 H

30/8-A-13 H/AH

30/8-1S

30/8-

A-11 H

30/8-A-14 H

Tune Field

Horizontal gas producers

Pure gas depletion

Sand screen completion

Tarbert Formation Gas/condensate

HP/HT – 525 bar / 131 degC

Reservoir thickness 100m - N/G 0.85

porosity ~16%, permeability 10-200 mD

12 m oil rim – non commercial

30/5-2

Agenda – 03.06.24

Tune Key data

Initial clean-up / Normal Production Tune

Initial clean-up Tune

PDO To drilling rig (Deep Sea Delta) 2-3 weeks after final completion

Actual To Oseberg Field Centre (through 11 km of pipeline)

– DSD not applicable

– outstanding verifications to perform clean-up

– Safety risks: flare + HT/HP 6-12 months after final completion

Initial clean-up Tune – continue

November /December 2002

Focus Initial clean-up Possible problems related to condensate blocking

Strategy Gradually opening of well Controlled by bottom hole pressure (Pdewpoint = 509 bar)

Measurements P/T sensors down hole and at wellhead Gas flow meter Online density meter on Tune separator

A-14 H – well trajectory

Geological cross-section along the drilled wellpath 31/8-A-14 H

BCU

Heather/Upper Tarbert

Lower Tarbert

TD

T2B1

T2B4T2B2

T2B6T2B5

T2B3

Well 30/8-A-14 H

Horizontal section ~900 m

Completed mid May 2002

K/Cs-formate in reservoir section

30/8-A-12HT2T2B5

T2B6

T2B4 T2B3T2B2

T2B1

Heather/Upper Tarbert

Lower Tarbert

A-12 T2H – well trajectory

Horizontal section ~650 m

Completed mid Nov 2001

Initially K-formeat in reservoir section

Displaced to K/Cs-formate mid June 2002, as upper completion was set

Tracers placed @

Antimonium - 4444 mMD RKB

Scandium - 4675 mMD RKB

Top reservoir @

4178 mMD RKB

TD @

4834 mMD RKB

A-11 AH – well trajectory

BCU

Top ResHeather/

Upper Tarbert

“Lagoonal Event”

GOC

Lower TarbertOWC

Horizontal section ~350 m

Completed mid April 2002

K/Cs-formate in reservoir section

30/8-A-13H

T2B5

T2B6

T2B4

T2B2

T2B1

Upper Tarbert

Lower Tarbert

T2B3

A-13 H – well trajectory

Tracers placed @

Silver - 4616 mMD RKB

Cobalt - 5031 mMD RKB

Top reservoir @ 4241 mMD RKB

4829 mMD RKBLagoonal event @ 5026 mMD

RKB

Reservoir section ~900 m

Completed mid Dec 2002

K-formate in reservoir section

Only well not displaced to K/Cs-formate

Overall performance Initial Clean-up Left for 6-12 months before clean-up

Planned for 2-3 weeks 10 - 24 hours per well Well performance

Qgas 1.2 – 3.6 MSm3/d PI 35 – 200 kSm3/d/bar Well length sensitive No indication of formation damage

– Match to ideal well flow simulations (Prosper) - no skin

Indications of successful clean-up Shut-in pressures   Water samples during clean-up

– Formate and CaCO3 particles Registered high-density liquid in separator Tracer results

– A-12 T2H non detectable– A-13 H tracer indicating flow from lower reservoir first detected 5 sd after

initial clean-up <-> doubled well productivity compared to initial flow data No processing problems Oseberg Field Center

SIWHP SIDHP SIWHP SIDHPbara bara bara bara

A-11 AH 169 - 388 -

A-12 T2H 175 487 414 510

A-13 H 395 514 412 512

A-14 H 192 492 406 509

Before After

3350

3400

3450

3500

3550

3600

0 100 200 300 400 500 600 700 800 900 1000

Well length [m MD]

Dep

th [

m T

VD

MS

L]

A-11AH

A-12HT2

A-13H

A-14H

A-11 AH plugged back

Return of completion fluid

No quantitatively control of liquid flow during start-up and first weeks of production

Spot ”water” samples of clean-up flow from A-12 T2H and A-11 AH

s.g. 0.8 - 1.33 pH 7.8 – 8.7 CaCO3 particles Crushed Formation particles

Normal Production

Stepwise increase in production to monitor well behaviour (January 2003) Possible problems related to condensate blocking Production reached PDO defined plateau rate of 9 MSm3/d on

January 24th

No negative effect on well productivity has been registered Ion analysis of produced water (January) - high content of

Potassium

Pigging operation in March and June – minor/no formate

Status June 2003 All four wells producing Well productivity as expected Gas production 12.4 MSm3/d Condensate 23 000 bbls/d