34/4-10 R

General

The purpose of the well 34/4-10 was to test the hydrocarbon potential of the Delta prospect located NW of the Snorre Field in block 34/4. The Delta prospect is a NE-SW oriented structural trap at the rim of the Marulk Basin. The main objective was to test the lithology and the presence of hydrocarbons in possible sandstone units within the Heather Formation. The well had as secondary target the Brent Group. Planned TD for the well was 50 m into the Statfjord Formation.

Operations and results

The well was spudded with the semi-submersible rig "Transocean Arctic" 12 February 2000 and reached a total depth of 4246 m in Statfjord Formation 7 April 2000.

After 13 3/8" casing at 2380 m the well was temporarily plugged and abandoned due to onshore rig-repair at Ågotnes.

After 13 days the well was re-entered as 34/4-10 R. The well was drilled water based to 2385 m and oil based from 2385 m to TD.

In the Upper Jurassic sequences no sandstones were found and therefore no core was taken. The Heather Formation was therefore thinner than prognosed. However, a 103 m thick oil bearing, Aalenian to lower Bajocian, Brent sequence was proven. It is an oil down to situation with 10 m net pay. MDT sampling was carried out in the oil column at 3966.5 m. Six sample bottles were filled, 5 SPMC bottles (450 cc) and 1 MRSC 1 gallon sample chamber. About 50 litres of formation fluid was pumped out before sampling was commenced resulting in a draw down during sampling of about 165 bar. PVT analysis indicated a moderately light oil (GOR 135 sm3/sm3, 0.850g/cc - 0.69 g/cc at reservoir conditions) with about 30% sample contamination by mud filtrate.

One 30 m core was taken in the best sandstone interval from 3953.0 - 3980.4 m. The core shows a classical prograding sequence from lower shore face to upper shore face, with a sequence boundary/ ravinement surface near the top. Above this a sandy transgressive interval is interpreted. At the top of the Brent