The Telford field is an oil and gas accumulation located in the UK sector of the North Sea. As a subsea tieback to existing production infrastructure this development might at first appear to be typical of many similar projects completed in recent years. However, the Telford story is interesting for two reasons. Firstly, the individual reservoirs making up the development are very different in nature and would be uneconomic on a stand alone basis. Secondly, the rapid development of the area to ensure maximum project value was a critical success factor. Achieving this hinged on the speedy resolution of a cross boundary equity issue which subsequently led to the formation of a joint operator sub-surface team for the reservoir development.
This paper focuses on the sub-surface aspects of the development and how the application of state-of-the-art technology coupled with a phased approach has led to the development of what was previously considered to be a marginal field. The rapid commercial agreement reached to enable the development to proceed and the success of the joint sub-surface team are considered. The paper aims to demonstrate that even small, complex accumulations can be developed successfully by an experienced operator determined to overcome traditional barriers to success.
The Telford Field is located in Blocks 15/21a and 15/22 of the United Kingdom Continental Shelf. The area is located approximately 170 km northeast of Aberdeen, 9 km south of the Scott Platform. The Telford field is an elongate structure measuring 11 km by 1 km. It comprises four separate accumulations trapped within structural compartments of late Jurassic Piper Formation sandstones. The reservoir is sealed and sourced by the overlying Kimmeridge Clay formation which is also Late Jurassic in age. The various accumulations have been named Central, West and East Telford and Marmion. Total STOIIP prior to development was estimated to be between 107 and 126 mmstb with a corresponding GIIP of 181 to 211 bcf. The location of the field and each accumulation is described in Fig. 1.
Full exploitation of the Telford area will ultimately be achieved by a two phase development. This will consist of the tie-back of sub-sea completed wells via manifolds and flowlines to the Scott Platform. The phasing of the development is to allow for processing restrictions at Scott and to permit further appraisal of the field. Phase 1 is now complete and has seen the development of the core area consisting of Central Telford and Marmion. Phase 2 will involve the appraisal and development of the West and East Telford areas and of the West Marmion prospect.
This paper describes the first phase of the development and the initial appraisal of West Telford. The second phase of the Telford development is expected to begin in 1998.