GULLFAKS

Discovery year
1978
Wellbore
Status
Producing
Licence

Operator:

Equinor Energy AS

Area:

North Sea

Production start:

22.12.1986

Historical investments per 31.12.2017:

94 923 MILL NOK (nominal)

Future investments from 2018:

25 470 MILL NOK (real 2018 NOK)

PRODUCTION FROM THE FIELD

Source: The Norwegian Petroleum Directorate

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PRODUCTION FROM THE FIELD

Development

Gullfaks is a field located in the Tampen area in the northern part of the North Sea. The water depth in the area is 130-220 metres. Gullfaks was discovered in 1978, and the plan for development and operation (PDO) for Gullfaks Phase I was approved in 1981. A PDO for Gullfaks Phase II was approved in 1985. Production started in 1986. The field has been developed with three integrated processing, drilling and accommodation facilities with concrete bases (Gullfaks A, B and C). Gullfaks B has a simplified processing plant with first stage separation. Gullfaks A and C receive and process oil and gas from Gullfaks Sør and Visund Sør. The Gullfaks facilities are also involved in production and transport from the Tordis, Vigdis and Visund fields. Production from Tordis is processed in a separate facility on Gullfaks C. PDO for Gullfaks Vest was approved in 1993, and for recovery from the Lunde Formation in 1995. An amended PDO for the Gullfaks field, covering prospects and small discoveries, which could be drilled and produced from existing facilities, was approved in 2005. An amendment to the Gullfaks PDO, covering Phase I production from the Shetland/Lista deposit, was approved in 2015.

Reservoir

Gullfaks produces oil from Middle Jurassic sandstone in the Brent Group, and from Lower Jurassic and Upper Triassic sandstone in the Statfjord Group and Cook and Lunde Formations. Recoverable oil is also present in fractured carbonate and shale in the overlying Shetland Group and Lista Formation. The reservoirs lie at a depth of 1,700-2,000 metres in rotated fault blocks in the west and a structural horst (raised fault block) in the east, with a highly faulted area in between. Reservoir quality is generally good to very good in the Jurassic reservoirs within each fault compartment, but poor reservoir communication is a challenge for pressure maintenance.

Recovery

The drive mechanism for the main reservoirs is primarily water injection, with gas injection and water alternating gas injection (WAG) in some areas. The drainage strategy for the Shetland/Lista reservoir had been depletion, but pressure support by water injection is now initiated.

Transport

Oil is exported from Gullfaks A and Gullfaks C via loading buoys onto tankers. Rich gas is transported by Statpipe for further processing at the Kårstø terminal.

Status

Drilling of new wells on Gullfaks has been challenging for many years due to overpressured areas in the Shetland/Lista interval. Production from the Shetland/Lista reservoirs has gradually contributed to reduced overpressures and improved drillability. Twelve new wells for water injection and production were drilled in 2018 and production performance has been above expectations. Additional wells will be drilled continuously from all platforms in 2019. Pilot water injection as a new drainage strategy for the Shetland/Lista reservoirs was implemented in 2018. An amended PDO for Shetland/Lista Phase II, covering water injection and new wells, has been submitted to the authorities.

ACCRUED INVESTMENTS IN NOMINAL NOK

Source: The Norwegian Petroleum Directorate

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ACCRUED INVESTMENTS IN NOMINAL NOK

NPD's CURRENT RESOURCE ESTIMATES

All numbers in mill. Sm3 o.e.

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NPD's CURRENT RESOURCE ESTIMATES – All numbers in mill. Sm3 o.e.
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