7119/9-1

General

Exploration well 7119/9-1 is located on the Ringvassøy ? Loppa Fault Complex west of the Snøhvit Field area. The well was designed to test a narrow horst, elongated in a NE-SW direction. The horst brings the main prospect, the Middle to Lower Jurassic Sandstones up to a depth of about 2700 m, in a position surrounded with Cretaceous Shale. The well is located close to the top of the horst. This target was found gas bearing in the two nearest wells: 7119/12-3 to the south, located in the same structural trend, and 7120/7-1, located higher up toward the Hammerfest Basin to the south-east.

Operations and results

The well was spudded with the semi-submersible installation Byford Dolphin on 28 June 1984 and drilled to TD at 3248 m in Late Triassic rocks. The well took a kick at 2744 m where a pit gain of 2 m3 was observed. Some technical problems occurred on the rig during a wiper trip before final logging of the 8 1/2" hole. During logging of the same sequence the RFT tool got stuck twice but was recovered in both cases. The well was drilled using water-based mud.

The well drilled through mainly claystone and shale formations down to top Jurassic at 2702 m. The lower Cretaceous Kolmule Formation was found silty and sandy between 2400 m and 2450 m. Top Jurassic Hekkingen Formation was penetrated at 2702 m and contained two good reservoir sections, a Middle ? Early reservoir and a deeper Pliensbachian reservoir. Above the upper reservoir zone 46 m of Late Jurassic shale was drilled. This sequence consisted of an upper Volgian ? Kimmeridgian sequence and a lower Oxfordian-Callovian shale sequence separated by an Oxfordian unconformity near 2719 m (more accurate depth cannot be proven due to logging problems in this section of the well). The upper Jurassic sandstone reservoir (Stø Formation) was penetrated at 2748 meters. The reservoir was well developed with a 120 meter gross thickness. The two cores cut near the top of t