Abstract
For developing the Snorre North area which started its production on June 2001, various scenarios had been examined since its start of evaluation of a development plan of the Snorre South. After several screening processes, the following three alternatives were selected for detailed technical and economical evaluation.
Case A: Subsea completion, tied-in to Snorre TLP (Tension leg platform).
Case B: Processed and storage at FPSO (Floating production, storage and offloading).
Case C: SSDPV (Semi-submergible drilling and production vessel) with drilling facilities. Processed oil is transferred to the Statfjord field via a new pipeline.
When development plans are evaluated, it is very important to introduce estimated effects based on field experience and expected future technology development as well as detailed evaluation. The Snorre group had had experiences of operation on both a floating production system and a subsea completion system and tried to reflect these experiences into the concept selection.
When impact on production profiles and reserves by changes in development solutions is evaluated, it is a normal procedure to carry out simulation studies with parameters defined for a specific solution and changes of reserves in different development scenarios are evaluated. Because of difficulties in defining parameters, however, there exist risks in the results of the simulation studies
In concept selection for Snorre North development, the following four technical topics were evaluated; well length and complexity, WAG (Water Alternating Gas) feasibility, data acquisition and zonal isolation opportunities. Based on this evaluation, Case C (SSPV) provided the highest recoverable reserves and economics among the three alternatives and was selected for the development solution of the Snorre North area.
