Lancaster Oil and Gas Field, West of Shetland

The Lancaster field is the first basement discovery made by Hurricane Energy. Image courtesy of Hurricane Energy.

The Lancaster field lies in the West of Shetlands area offshore UK. Image courtesy of Hurricane Energy.

A two-well appraisal well programme was launched by Hurricane to assess the potential of the Lancaster field. Image courtesy of Hurricane Energy.

A horizontal well was drilled by Hurricane using Transocean Sedco 712 drilling rig. Image courtesy of Hurricane Energy.

Tests carried out at the field achieved sufficient flow rates. Image courtesy of Hurricane Energy.

The Lancaster field is located in blocks 205/21a, 205/22a and 205/26b of the West of Shetlands area offshore UK in water depths of 160m. The prospect is 100% owned and operated by Hurricane Energy.

Discovered in 2009, the field is Hurricane’s first basement discovery located 4,000ft beneath the seabed. Hurricane is currently assessing the potential of the field and planning a phased development.

Lancaster field geology and reserves

The Lancaster field includes a highly fractured granitic basement reservoir, which includes a number of fractures at various levels. Fracturing in the reservoir is the result of a range of original cooling joints formed through numerous tectonic activities more than 2.4 billion years ago.

The 1C, 2C and 3C contingent resources of the field are estimated at 62 million barrels, 207 million barrels and 456 million barrels respectively.

Lancaster offshore field exploration and appraisal

Hurricane drilled a horizontal well in 2014 using the Transocean Sedco 712 drilling rig to test the potential of the Lancaster prospect. The well flowed at the rate of 9,800 stock tank barrels of oil a day (STB/d) with oil of 38° API. The well was later suspended for conversion into a producer.

To further assess the resource potential of the Lancaster field, Hurricane launched a two-well programme including a pilot well and a horizontal sidetrack well.

The pilot well, spud in July 2016, was drilled to a depth of 1,620m TVDSS and encountered a hydrocarbon column of 620m. Drill stem testing conducted on the pilot well achieved a maximum flow rate of 11,000 barrels of oil per day (bopd) of 38° API oil. The well was completed and permanently abandoned in September 2016 before drilling of the horizontal sidetrack well.

Hurricane completed the horizontal sidetrack well in October 2016 and suspended it as a future producer. The well was tested and achieved a sustainable stable flow rate of 14,500STB/d. The results obtained from the sidetrack well were consistent with that of the horizontal well.

Hurricane also plans to drill an exploration well on the Halifax prospect located north-east of the Lancaster field. A previous well drilled on the Halifax prospect encountered oil and gas in sandstones above the basement.

Drilling of the exploration well will help in assessing the availability of mobile oil outside of the Halifax closed structure. It can significantly extend the Lancaster oil accumulation beyond the existing license boundary and increase the potential of the field.

Lancaster offshore field development

Hurricane is planning to carry out a phased development of the field considering the huge potential of Lancaster.

The company signed an agreement with Bluewater Energy Services in November 2016 to lease the latter’s Aoka Mizu floating production storage and offloading (FPSO) vessel for use at the Lancaster field. The FPSO will be part of the early production system (EPS) phase of the field development.

The Competent Person’s Report developed for the field estimates that a flow rate of 8,000bopd can be achieved from the basement.

Contractors involved

An alliance of Technip and FMC Technologies has been contracted to provide subsea solutions for the EPS of the field. Constain was chosen to provide development options for the field.

Schlumberger’s Intersect simulator was used by Hurricane to assess the geological characteristics of the Lancaster field reservoir.

RPS Group prepared the Competent Person’s Report for the field.