16/1-15 A

General

Well 16/1-15A is a sidetrack to Well 16/1-15, drilled on the western side of the Utsira High in the North Sea. The primary well proved Tellus to be a continuation of the Luno Discovery, now officially named the Edvard Grieg Field. The objectives of the geological sidetrack, 16/1-15 AT2, were to prove thicker, high productivity sandstone sequences to add to the Luno reserves, and to provide seismic calibration of complex stratigraphy.

Operations and results

Appraisal well 16/1-15 A was kicked off at 599 m in well 16/1-15 on 6 April 2011. It was drilled with the semi-submersible installation Bredford Dolphin. The 12 1/4" hole was drilled to TD at 2041 m. When running 9 5/8" casing it got differentially stuck forcing a new sidetrack. It is believed that the casing stuck in Grid Formation sandstone. The 16/1-15 A well bore was thus plugged back to the 20" casing and the technical sidetrack 16/1-15 AT2 was kicked off from 584 m and drilled to final TD at 2175 m (2011 m TVD) in Basement rocks. The sidetrack was drilled with Performadril mud from kick-off to TD.

Well 16/1-15 AT2 proved 1 meter thick Intra Åsgard Formation Sandstone at 2067 m, overlying fractured basement. The sandstone was oil bearing and the basement had shows, but in this well bore the basement was found to be cemented and was considered unproductive. Oil shows were first recorded on the cores in the Intra Åsgard Formation Sandstone. They continued on the cores into the underlying basement where they were generally restricted to fractures. Below the cored interval sporadic shows were seen on cuttings down to a depth of 2124 m (1967.6 m TVD).

Four short cores were cut from 2066 to 2076.26 m, across