Field Development Planning of a Thin Compartmentalised Oil Column: Vincent Field, Offshore Western Australia
Hein Knipscheer, Ole Sundsby, Darren Baker, and Peter Griffiths
Woodside Energy Ltd, Perth, WA, Australia
Fast-track development of a thin compartmentalised oil column in a deepwater setting requires detailed full field layout planning before key subsurface data is available. Flexibility in layout of subsea infrastructure and wells is required to benefit of the enhanced definition of the resource while developing. A complicating factor is that the thin viscous oil column requires closely spaced horizontal wells with limited room for flexibility, since a shift of well location(s) impacts all other wells and layout of subsea infrastructure.
The Vincent Field is a relatively small oilfield off the north-western Australian coast in water depths of up to 400m. One discovery and 2 appraisal wells indicated the presence of a compartmentalised, biodegraded oil column with a variable thickness of 12 to 19 meters between a thin gas cap and a large water leg, all in very high quality fluvio-deltaic reservoir rocks. Direct hydrocarbon indicators from excellent quality seismic data were used to define the extent of compartments and potential differences in oil columns. Compartmentalisation is thought to be caused by a combination of stratigraphic seals and faults.
The chosen development is by long multilateral horizontal wells drilled from 2 production manifolds in a phased FPSO development. The locations of the manifolds were finetuned using late appraisal data and the number of drilling slots available is compatible with a later full field development. Tie-in points are provided for possible additional subsea infrastructure. The impact of compartmentalisation is thought to have been mitigated by drilling through potential stratigraphic barriers and sealing faults.
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