Frigstad D90 - MHWirth Version

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The D90 has been designed with highest focus on optimizing the drilling operation. Equipped with two identical well centers, each with 1,400 st lifting capacity, the rig has a redundancy and flexibility unseen on other rig designs. With station keeping ability in currents up to 6,7 knots, the rig can operate in area's where most ohter fails. Ability to transit with full set backs, 10.000 ft Riser in 110 ft stands and 60.000 ft drillpipe, saves days on each rig moove which again translate to saved overall cost.

The general arrangement of the unit has been carefully developed utilizing the extensive practical experience of the personnel at Frigstad Engineering and Frigstad Offshore. All aspects of equipment functionality and placement have been carefully considered to ensure that each process is safe and efficient.

Optimized rig design & efficiency

  • Full dual activity, 100 % redundancy
  • Quadruple drillpipe setback, 60.000 ft
  • Vertical riser storage, 10.000 ft -110 ft joints with additional 2.000 ft on deck.
  • Trip saver with skidable N-line tensioner system
  • Cylinder rig; No slip & cut
  • Multi-machine control, enabling highest efficiency drilling operations
  • Designed and prepared for all third party operations
  • Triple mud system
  • Handsfree gooseneck system
  • Innovative cuttings handling system w. storage in coloumn
  • BOP depth-compensated accumulator bottles
  • Large deck space and internal storage/workshops
  • Hight transit speed
  • Rig moves with full set-backs


  • Drill production & exploration wells
  • Batch Drilling
  • Completion
  • Intervention
  • Wire line operations
  • Plugging of wells
  • Well testing and clean-ups
  • Coiled tubing
  • Managed pressure drilling
  • 20 K Prepared


Outline Specification

SOLAS 2008, MARPOL 1973/78, IMO MODU CODE 2009, all with latest amendments
Maximum wind velocity 70 knots / 100 knots
Wave height Hs/Max 15.8/24.9 m (51.8/96.5 ft)
Air gap (Operating/Survival) 10.5 /16.5 m (34.4/54.1 ft)
Length of pontoons 117 m (383.8 ft)
Width & length, pipe rack deck 89 x 81 m (292 x 265.7 ft)
Height to pipe rack deck (ABL) 43.3 m (142 ft)
Draft (operational) 24 m (78.7 ft)
Draft (survival) 18 m (59 ft)
Displacement (operational) 69,802 t (76,943 st)
Displacement (survival) 61,525 t (67,819 st)
Displacement (transit) 51,448 t (56,711 st)
Water depth (max) 12,000 ft (3,658 m)
Drilling depth (max) 60,000 ft (18,288 m)
Bulk mud 440 m³ (15,538 ft³)
Bulk cement 440 m³ (15,538 ft³)
Sack material, upper hull 9,000 sacks
Base oil for mud, pontoon 653 m³ (4,106 bbls)
Liquid mud / brine, upper hull 1,603 m³ (10,100 bbls)
Liquid mud / brine, pontoon 2,144 m³ (13,485 bbls)
Diesel fuel oil (MDD), pontoon 4,694 m³ (29,524 bbls)
Drill water, pontoon 4,811 m³ (30,260 bbls)
Potable water, pontoon 1,256 m³ (7,900 bbls)
Open pipe rack deck area 4,000 m2 (43,055 ft2)
Variable deck load (max oper.) 10,000 t (11,023 st)
Variable deck load (max transit) 6,700 t (7,385 st)
Payload (max operational) 16,700 t (18,408 st)
Cutting storage, column 600 m3 (21,189 ft3)
Total capacity of 200 persons with all single person bedrooms with windows. Ample office space and service facilities.
Deck cranes Two (2) 150 t revolving deck cranes with 57 m boom. Capable of handling under water thruster change out. Two (2) 14 t knuckle boom cranes for tubular handling.
Cargo handling and logistics Two (2) 6 t cargo elevators & several forklifts to service storage and machinery areas on pipe rack deck and inside the deck box and pipe rack deck including: engine rooms, mud pump room, cement unit room, workshops, sack storage, warehouse, galley stores
Main power / emergency power Eight (6) diesel engines, each with 5,760 kW capacity. Total installed power is approx. 46, 000 kW (62,500 BHP).
Power distribution 11 kW AC main switchboards and DP with MP + AW drives and WM system.
Thruster DP Class 3. Eight (8) 4,5 MW azimuth thrusters (DNV DYNPOS AUTRO ER).
Dynamic positioning DYNPOS AUTRO (DP3) (optional)
Mooring system Four (4) double drum winches with 600 meters of 83 mm wire and eight (8) fairleads for connection to pre-set mooring system (DNV POSMOR ATA).
Drilling rig MHWirth Dual Ram Rig. Both port and starboard have 1,400 st hoisting capacity with 1,250 st load in elevator and dual handling capabilities. Setback for 60,000 ft quadruple drill string / casing in triple stands. Two (2) diverters / flow lines.
Rotary table Two (2) MHWirth 75.5” rotary with independent drive.
Top drives Two (2) MHWirth top drives, each with 1,250 st capacity.
Riser tensioners Six (6) MHWirth Direct Acting Tensioner (DAT) systems. 5,000 kips. 1 cylinder less in system gives 3,700 kips in midstroke. Max load capacity 2,500 st.
BOP and riser Two (2) 18 ¾” 15k, 7 cavity BOP 21” riser, 55 ft joints with K&C, booster and hydraulic lines. Vertical “Clip type” marine riser rack for 10,110 ft, 110 ft stands (2 x 55 ft lengths). Storage onboard for 12,000 ft of riser. Designed for up to 8-ram BOP, an
Drill string Drill strings with subs, drill collars, heavy weight drill pipes, casing.
Mud pumps and treatment system Four (4) main mud mumps, triplex 2,200 HP, 7,500 psi wp. Four (4) triple deck multi-sizer shakers. Two (2) desilters, two (2) centrifuges, one (1) gumbo conveyer, two (2) degasser units and two (2) 60 bbls trip tanks. Storage of 600 m3 cuttings in columns
Helicopter deck capacity Designed for Sikorsky S61/S92, MI8 and EH 101 helicopters. Max 15,6 tons.
Life-saving equipment Four (4) lifeboats with total capacity of 400 persons (98 kg, 21” seats). Sixteen (16) inflatable life rafts with capacity of 25 persons each. Two (2) fast rescue boats.