STATOIL SETS ANOTHER MARK FOR EXTENDED REACH

Norways's Den norkse stats oljeselskap AS has broken its world record for extended reach drilling. Statoil's C3 development well, drilled from Statfjord Platform C in the Norwegian North Sea, has a horizontal reach of 19,905 ft. Measured depth is 23,786 ft, true vertical depth 8,850 ft. The well is in the final stages of completion. Statoil set the previous extended reach record in 1990 with a 16,425 ft horizontal displacement in the C10 well, also drilled from Statfjord Platform C.

April 15, 1991

2 min read

Norways's Den norkse stats oljeselskap AS has broken its world record for extended reach drilling.

Statoil's C3 development well, drilled from Statfjord Platform C in the Norwegian North Sea, has a horizontal reach of 19,905 ft. Measured depth is 23,786 ft, true vertical depth 8,850 ft.

The well is in the final stages of completion.

Statoil set the previous extended reach record in 1990 with a 16,425 ft horizontal displacement in the C10 well, also drilled from Statfjord Platform C. The well, which is flowing 30,000 b/d of oil, has produced more than 11 million bbl.

C3 logs showed a 225 ft vertical oil column in excellent Upper Brent sands. C10 had a vertical oil column of 210 ft.

Both wells were drilled north from Statfjord Platform C, one of three concrete structures in the North Sea's biggest producing field, which extends into British waters. C10 helped boost Statfjord field production to about 815,000 b/d in February.

CHANGES FOR C3

Statoil changed the drilling equipment for C3, based on experience with C10. The platform rig was fitted with top drive and upgraded to handle 6 5/8 in. and 5 1/2 in. drillpipe to improve hole cleaning and increase drilling torque capacity.

The casing program also was changed.

The 20 in. casing was replaced with 24 in. casing and an 18% in. liner. Statoil said this reduced the length of the 17 1/2 in. hole section and allowed an increase in the section's sail angle to 70 from 60.

The 12 1/4 in. hole section was 11,830 ft, with an average sail angle of 80 degrees. The 12 1/4 in. and 8 1/2 in. sections were drilled with no problems.

The well took a total of 110 days to drill, including 30 days lost to mechanical problems with drillpipe and top drive.

Later this year Statoil will spud another long horizontal displacement well. To be a water injector in the north part of Statfjord field, it is expected to have a horizontal reach of about 18,040 ft between the previous and current world records.