Development

Tyrihans is a field in the Norwegian Sea, 25 kilometres southeast of the Åsgard field. The water depth in the area is 270 metres. Tyrihans was discovered in 1983, and the plan for development and production (PDO) was approved in 2005. The field is developed with five subsea templates tied-back to the Kristin field, four templates for production and gas injection and one template for seawater injection. Gas for injection and gas lift is supplied from the Åsgard B platform. Production started in 2009.

Reservoir

Tyrihans produces gas and condensate from two reservoirs: Tyrihans South has an oil column with a condensate-rich gas cap and Tyrihans North contains gas and condensate with an underlying oil zone. The main reservoir in both deposits is in the Middle Jurassic Garn Formation at a depth of 3,500 metres. The reservoirs are homogenous and of good quality. In addition, one well produces oil from the Ile Formation.

Recovery

Production is based on gas injection from Åsgard B to Tyrihans South. In addition, subsea pumps are used for injection of seawater to maintain pressure in both Tyrihans North and Tyrihans South. Tyrihans also benefits from the low-pressure production drainage strategy started on the Kristin field in 2014.

Transport

The well stream is tied-back to the Kristin field for processing. Gas is exported from Kristin via the Åsgard Transport System (ÅTS) to the Kårstø terminal, while oil and condensate are transported by pipeline to the storage ship Åsgard C for export on shuttle tankers.

Status

Gas injection from Åsgard began the same year as the Tyrihans field started production. Gas injection has been prolonged beyond what was originally planned in the PDO, and the injection strategy is evaluated on a yearly basis. Production from Tyrihans is dependent on Kristin, which has limited gas and water handling capacity. However, recent tests have proven a better processing capacity than previously thought. A production well with a horizontal exploration extension will be drilled on Tyrihans North in 2019.