16/1-9

General

The 16/1-9 Draupne prospect is located on the eastern margin of the South Viking Graben in the North Sea. The structure is situated in the eastern part of the Gudrun Terrace and the western flank of the Utsira High. The primary target was a faulted anticline trap within Hugin/Sleipner reservoir sandstones of Middle Jurassic Bajocian - Callovian age. A secondary target was mapped on a four way dip closure within the Paleocene top Heimdal level, the Gugne prospect. Well 16/1-9 was planned as a vertical well with TD ca 50 m into the Hugin/Sleipner Formation if water bearing, or ca 50 m into the Triassic Skagerrak Formation in case of a discovery.

Operations and results

Wildcat well 16/1-9 was spudded with the semi-submersible installation Bredford Dolphin on 19 February 2008 and drilled to TD at 2544 m in the Late Triassic Skagerrak Formation. A pilot hole was drilled prior to the 36" section. No signs of shallow gas were observed or seen on MWD logs. Significant downtime resulted from a shallow water flow beside the well (5.2 days), wait on weather (4.3 days), BOP acoustic failure (3.5 days), poor hole conditions (2.9 days) and stuck wire line (2.2 days). The well was drilled with Seawater and sweeps down to 600 m, with KCl/GEM mud from 600 m to 1281 m, and with Performadril mud from 1281 m to TD.

The secondary target Heimdal Formation was entered at 2126.0 m (2123.2 m TVD), approximately 100 meters deeper than the prognosed depth, and it was dry. The Sleipner Formation sandstone was encountered at 2399.0 m (2393.2 m TVD), 167 TVD meters deeper than prognosed. The Skagerrak Formation was encountered at 2411 m (2405 m TVD), 23 TVD meters shallower than prognosed. The wire line logs proved a thin gas cap from 2399 m (2368 m