25/11-14 SR

General

Well 25/11-14 SR re-entry was drilled centrally on the Balder Field on the Utsira High in the North Sea. This field was discovered in 1967 by the 25/11-1 well, and was the first well on the Norwegian shelf that proved oil. Primary well 25/11-14 S was planned to be completed for a long term test by the FPV Petrojarl 1. The well was planned deviated with kick-off at 1060 m in order to avoid possible shallow gas at 235 m, 254 m, and 515 m. The main objective of this well was to test two Paleocene Heimdal Formation sands; the IB4 sand at 1863 m and the IB3 sand at 1897 m. The Heimdal Formation had previously proved oil-bearing in the three neighbouring wells 25/11-6, -7, and -8. Eocene sands constituted a secondary objective for testing. Based on data from surrounding wells, no abnormal pressure was expected. The surface location and well trajectory for this well, was designed so that a later plug-back and sidetrack to a horizontal completion could be accomplished.

The 25/11-14 SR re-entry was made to fulfil the primary objective of well 25/11-14 S, which was terminated too shallow and without logging and testing due to stuck pipe.

Operations and results

Appraisal well 25/11-14 SR kicked off at 1571 m in 25/11-14 S on 19 October 1990. It was drilled with the semi-submersible installation Byford Dolphin to final TD at 2081 m in sands of the Paleocene Heimdal Formation IB3 sand. After coring the IB3 sand the well was drilled a further 11 m but was TD'ed early as it encountered lost circulation problems between 2077 and 2081 m. It was decided at this point to run casing as quickly as possible to avoid further formation damage prior to the well's main objective of the extended production test. The well was drilled with seawater down