Hurricane Energy has already put in the hard yards for development options for its Halifax prospect, with engineering studies performed by Costain Upstream during an 18-month period to select the best concept.

Its 205/23-3A well on the Halifax prospect West of Shetland (WoS) has been confirmed as an oil discovery that is linked to the nearby Lancaster Field, making the Greater Lancaster Area (GLA) the largest undeveloped discovery on the U.K. Continental Shelf, according to U.K.-based Hurricane. Information from the well is “preliminary and will be updated following detailed analysis once the final well data and third-party reports have been received and analyzed.”

During the concept selection process, 45 potential options were assessed, with more than 45 possible concepts scenarios considered, leaving the choice between a floating production system and a production platform.

Once the floater concept was deemed favorable, other questions arose such as whether to use an FPSO vessel, a Sevan cylindrical hull floater or even the Octabuoy option before Chinese designer Cosco scrapped the concept.

Hurricane decided an FPSO development with subsea facilities that could be used as “a new infrastructure hub for the WoS area” was the best way forward.

The final decision was to have a phased development, with Phase 1 using a leased unit to allow an early production system to get up and running before moving into Phase 2 and the full development stage using a purchased FPSO unit.

Hurricane believes the transition point between a leased and purchased FPSO unit is about eight years.

“In the challenging environment we live in today, an approach on how field collaboration can deliver a hub concept rather than a field specific solution WoS” was the best plan, according to Hurricane.

“The EPS [early production system] is a natural precursor to a larger phased development providing the required data to optimize the Lancaster full field development. For a hub located close to Lancaster, in shallow water, we believe there is a real opportunity for the industry to demonstrate a collaborative approach to maximizing the economic recovery of the area.”

Halifax Well Data

The Halifax well encountered a hydrocarbon column of at least 1,156 m (3,792 ft), supporting Hurricane’s view that the prospect is linked to the Lancaster Field to form a single large hydrocarbon accumulation, Hurricane said in a March 27 news release.

“We believe that the GLA is a single hydrocarbon accumulation, making it the largest undeveloped discovery on the U.K. Continental Shelf,” Hurricane CEO Robert Trice said in the release.

Hurricane said the reservoir interval hit is pervasively fractured and has porosities similar to those at Lancaster. The company believes the deeper oil down at 1,846 m (6,056 ft) true vertical depth subsea (TVDSS) identified in the Halifax well, compared with an oil water contact (OWC) at Lancaster at 1,678 m (5,505 ft) TVDSS, is likely caused by a tilted OWC.

The Halifax well was drilled by the Transocean Spitsbergen rig and cased at 1,179 m (3,868 ft) TVDSS, and it further drilled to 1,801 m (5,909 ft) and a drillstem test was conducted. “However, constrained by budget, available time and the safety requirement of drilling overbalance, the well was unable to clean up and recovered only traces of formation oil to surface,” Hurricane said in the release.

The well was suspended. Hurricane plans to deepen the well, conduct additional test or pursue both.

Preliminary third-party analysis from the Halifax well indicates:

  • A very significant hydrocarbon column of at least 1,156 m (3,793 ft) is present within the basement extending well below local structural closure (which is at 1,040 m [3,412 ft] TVDSS);
  • The basement reservoir below the final casing point (1,179 m [3,868 ft] TVDSS) is pervasively fractured (based on initial analysis of borehole image logs processing); and
  • Porosity is consistent with that at Lancaster based on initial petrophysical analysis.

The rig has demobilized and is no longer on hire to Hurricane.

‘Significant Moment’

So far, Hurricane has drilled one development well (Lancaster sidetrack), one appraisal (Lancaster Pilot) well, one intervention on the 2014 horizontal well (in preparation for well completions in second-quarter 2018) and two exploration (Lincoln and Halifax) wells, Trice said.

“We have now completed the well stock for our early production system and in the process materially increased and de-risked the resource volumes associated with Lancaster,” he added. “The exploration wells on Lincoln and Halifax have resulted in the discovery of extensive oil columns, and we therefore expect that later iterations of our CPR [Competent Person’s Report] will significantly upgrade our resource base on both the GLA and the Greater Warwick Area.”

A final investment decision for the Lancaster project is on track for the end of first-half 2017.

“We will process the data from the Lincoln and Halifax wells and expect to release updated CPRs toward the end of 2017,” Trice said.

—Steve Hamlen

Offshore