Presentation given by Norsk Hydro and M-I at IQPC conference in June 2003. Describes the use of potassium formate brines as the reservoir drilling and completion fluids in four wells in the Tune field development, offshore Norway.

1. Tune Case (NH)
Experience from Drilling and
Completion using formate based fluids
Drilling & Completion Fluid Seminar, Aberdeen 03.06.24
By Atle Nottveit, Manager Well Completion

2. Agenda – 03.06.24
Tune Field Information
Mud and completion fluids criteria
Fluids alternative
Drilling and completion experience

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Tune Field data
 Location
 Block 30/8
 ca. 130 km northwest of Bergen
 10km west of Oseberg Field Centre
 Fluids
 Gas/ condensate @ 525 bar, 131 o
C
 Production strategy
 Pure gas depletion
 Reserves
 Gas
– 22.9 GSm3 Phase1
– (27.1 GSm3 incl. Phase 2 &3)
 Condensate:
– 5.8 MSm3 Phase 1
– (7.0 MSm3 incl. Phase 2&3)
 Producers: 4 ( +1+1 Phase 2&3)
 Sub sea template, tie-in Oseberg Field
Centre
 2 x 11 km 11.5” Carbon pipelines
Oseberg
Tune
Oseberg Sør
Brage
Field Centre/
OSA/OSB/OSD
OSC
Oseberg Øst

4. Tune Field data

5. Fluids criteria
Drillability
 MW = 1.65sg
Open hole completion
 Minimum formation damage
 Avoid plugging of sand screens
 Fluid loss control, while running sand screen
Same type of fluid both for drilling and
completion
 Limitation of pit capacity at rigsite
(Deep Sea Delta)

6. Fluid alternatives
Alternative #1
 OBM as drilling fluid and run sand screen in same.
Alternative #2
 OBM as drilling fluid. Run screen through OBM with
LSOBM (Low solids oil based mud) in open hole.
Alternative #3
 Formpro (Potassium formate) RDIF as drilling fluid and
run screen in same.
Alternative #4
 Formpro (Potassium/Cesium formate) RDIF as drilling
fluid and run screen in same.

7. Fluid alternatives
Alternative #3 chosen, but during drilling,
well clean up was delayed from 2-3 weeks
until 1 year.
 Well A 14 an A 11 was therefore completed in
Potassium/Cesium Formate based Formpro.
 Well A 12 AH displaced to Potassium/Cesium
formate based Formpro in reservoir section after 7
months.
 A 13 only well left with Potassium Formate based
Formpro.

8. Typical drilling fluid parameters
MW: 1.65 sg
PV: 21 - 30 cP
3rpm: 3 - 5 lbs/100 sq. ft.
HTHP: 9 - 11 mls
LGS: 320 – 420 (including CaCO3)

9. Drilling and completion experiences
Excellent hole cleaning
Lower friction than other WBM system
Stable wellbore
Aeration in fluid

10. Drilling experience

11. Drilling experience
Drilling
Drilling Down Time
Completion
Compl. Down time