Stella

Stella Oil and Gas Field Profile

Location and Geology

• The Stella oil and gas field is located in the UK section of the Central North Sea, specifically in blocks 30/6 and 29/10 NE Upper.
• The field contains two main reservoirs: the Andrew reservoir, which is a sandstone formation of Paleocene age, and the Ekofisk reservoir, which is a chalk formation of Cretaceous age. Below the Andrew reservoir lie chalk layers of the Cretaceous age.

Discovery and Appraisal

• The Stella field was discovered in 1979 when well 30/6-2 was drilled, encountering gas and condensate in the Paleocene Andrew sand and oil in the Ekofisk Chalk reservoir.
• The appraisal of the field involved five appraisal wells and three sidetracks, with the first appraisal well drilled in 1983 and additional wells drilled in 1996.

Reserves

• The field contains net 3P reserves of 18.4 million barrels of oil equivalent (mmboe), with proven reserves standing at 10.23 mmboe and net 2P reserves at 14.37 mmboe. These estimates were prepared by Sproule Associates for Ithaca Energy.

Ownership and Operation

• Ithaca Energy operates the field and owns a majority stake of 50.33%. Other stakeholders include Dyas UK with a 31.67% stake and Challenger Minerals International (CMI) with an 18% stake. Ithaca acquired the majority stake from Maersk Oil and a joint venture between Shell UK and Esso Exploration and Production UK in 2008 and 2009, respectively.

Development Plan

• The development plan for the Stella field involves drilling five production wells from a subsea drilling centre. A subsea pipeline will transport the hydrocarbons to a host facility, and a floating production unit will be used to develop the field.
• Ithaca plans to tie back two nearby discoveries, Harrier and Hurricane, to the Stella field to achieve cost synergies and develop Harrier simultaneously with Stella.

Contracts and Services

• Applied Drilling Technology International (ADTI), a subsidiary of Transocean, was awarded a turnkey contract to drill the field in October 2009.
• EPC Offshore was contracted in May 2011 to provide a managed service for the Stella area development.
• GE Oil & Gas Subsea Systems was awarded a $17 million contract in September 2011 to manufacture and supply shallow water vertical tree systems, controls, and SG1 wellheads.

Development Status

• The appraisal of the Stella field was successfully completed in 2010. Ithaca carried out detailed engineering works and developed a geotechnical programme for the field. A development concept select process was completed in October 2011, with Petrofac appointed to submit a field development plan to the Department of Energy and Climate Change by the end of 2011.

Financial and Operational Aspects

• Under the terms of the farm-out agreement, CMI paid 27% of the gross appraisal costs and may also fund a further Stella development well. The gross appraisal drilling costs were estimated at $35 million.
• Detailed production profiles and cash flow statements are part of the economic analysis provided by reports such as those from GlobalData.