Heavy (low API gravity) and viscous crudes are found in reservoirs in the Central and Northern North Sea and West of Shetland. Key issues associated with the development of heavy oil fields include:

• optimising downhole completion design to improve well productivity;

• use of horizontal well technology and multilateral/multibranch wells to place well-bores as close to recoverable oil as possible to overcome problems due to limited oil mobility;

• improved understanding of the complex chemistry of heavy oils to aid fluids handling in oil-water separators and flowlines.

In remote areas, such as West of Shetland, the feasibility of offshore processing of heavy crudes to produce more tractable (more easily pumped and transported), higher value fluids for export is also likely to be of increasing importance.

IOR techniques for viscous crudes such as hot water injection, steam flooding, in-situ combustion or downhole heating are likely to require very substantial reductions in technical risk and cost before any will be applied routinely offshore Northwest Europe.