34/4-6

General

Well 34/4-6 was drilled in the northern part of the Snorre Field. The main objectives were to test the northern outline of the field and to confirm the oil/water-contact and reservoir characteristics of the Upper Lunde Formation. The stratigraphy and reservoir characteristics of the Middle and Lower Lunde together with the Lomvi Formations were secondary objectives. Prognosed depth was at 3236 m in Triassic rocks.

Operations and results

Appraisal well 34/4-6 was spudded with the semi-submersible installation Vinni on 31 December 1995 and drilled to TD at 3282 m in the Late Triassic Teist Formation. The 26" section was hampered by bad weather and large parts of the period from the evening of 9 January up to 18 January was spent as WOW. When reaching 740 m the bad weather also made it necessary to disconnect the riser from the well head. Technical problems when attempting to re-latch the pin connector back on to the well head resulted in the remaining section down to TD at 920 m in the 26" section being drilled with no returns to the surface. The well was drilled with spud mud down to 530 m, with gel mud from 530 m to 920 m, with gypsum/polymer mud from 920 m to 2345 m, and with gel mud from 2345 m to TD.

Apart from the sandy Utsira Formation of Late - Middle Miocene to Pliocene age (1127.5 - 1239 m) and a sandstone unit within the Hordaland Group of Early Oligocene age (1358.5 - 1387 m), the upper section down to the Base Cretaceous Unconformity proved mainly claystones. No Jurassic rocks were encountered in the well. The Triassic Hegre Group consists of sandstones with minor shales and siltstones down to TD of the well. The target horizon, the Upper Lu