Blane

Blane Oil Field Profile

Location and Jurisdiction

The Blane oil field is a cross-border oil field located in the southern part of the North Sea, straddling the UK and Norwegian sectors. It is situated approximately 260 km east of Aberdeen, Scotland, at a water depth of about 70 meters (230 feet).

Ownership and Partners

The field is operated by Repsol Norge, a subsidiary of the Spanish petroleum company Repsol. The ownership interests are distributed as follows:

• DNO North Sea UK: 43.49%
• Repsol Sinopec Resources UK: 25%
• Dana Petroleum (a subsidiary of KNOC): 12.5%
• Repsol Norge: 18%
• DNO North Sea (ROGB): 1%.

Discovery and Development

The Blane field was discovered in 1989 through wildcat wells 1/2-1 and 30/3a-1 in the Norwegian and UK sectors, respectively. The field development plan was submitted in May 2005 and approved by both UK and Norwegian authorities in July 2005. Due to its cross-border nature, the field was unitised, with the UK holding 82% and Norway holding 18% of the field.

Geology and Reservoir

The Blane field reservoir is located at a depth of approximately 3,100 meters beneath the seabed and consists of Paleocene sandstone of the Forties Formation. The reservoir is highly over-pressured and contains high-quality oil with an API gravity of 42°. The field is characterized by a four-way structural closure in the Central Graben area.

Development and Infrastructure

The field was developed as a subsea tieback to the Ula platform, which is located about 35 km north-east of the Blane field in the Norwegian sector. The development includes:

• Two horizontal production wells (A and B) drilled in October 2006.
• A third sub-vertical water injection well (C) drilled in 2007.
• A subsea production manifold and associated pipelines, including a 10-inch production pipeline, a 6-inch gas lift line, and an 8-inch water injection pipeline.

Production

First production from the Blane field began in September 2007. The production wells are equipped with gas lift facilities to manage high water cuts. However, gas lift operations were temporarily discontinued in 2009 due to subsea pipeline leakages, which were repaired by August 2010. The average production rate in September 2010 was approximately 11,964 barrels of oil per day, with an expected peak rate of 17,000 barrels of oil equivalent per day.

Processing and Transportation

The wellstream from the Blane field is processed on the Ula platform, which includes a dedicated separator and individual metering packages for gas, oil, and water. The crude oil is then transported through the Ula oil pipeline to the Ekofisk field and further exported via the Norpipe oil pipeline to Teesside, UK.

Recent Developments

In February 2022, Repsol Norge received approval from the Petroleum Safety Authority Norway (PSA) to extend the life of the Blane field until July 2027. This extension was necessary as the original production licence in Norway was set to expire in the fourth quarter of 2022.

Reserves

The Blane field is estimated to contain proven and probable reserves of approximately 30.4 million barrels of oil equivalent (mboe), with nearly 97% of these reserves being oil.

In summary, the Blane oil field is a significant cross-border project in the North Sea, operated by Repsol Norge and involving multiple international partners. Its development and production are closely tied to the Ula platform, ensuring efficient extraction and processing of its high-quality oil reserves.