Historically, most UKCS production has been of light oil, 30° API and above. However, since 1993, a number of heavy oil fields have been brought on production. This paper reviews the history of UKCS heavy oil, the challenges overcome to bring these fields to development, and the future outlook.

The occurrence and distribution of the UKCS heavy oil in place is discussed. A specific correlation to estimate reservoir viscosity from API gravity is presented. Productivity of heavy oil reservoirs is compared with light oil developments, different categories of heavy oil reservoirs are identified, and the use of horizontal or multilateral well technology to achieve acceptable production rates is discussed. The implication of well productivity testing (e.g. extended well testing) of appraisal wells is discussed.

The development challenges that have been overcome in current developments (Harding, Gryphon, Alba, Captain) are reviewed, in particular focusing on well productivity, pressure support, recovery efficiency (management of gas and water coning, areal sweep), and oil water separation. The paper will also review the cost and risk management strategies that need to be adopted to enable the economic exploitation of these heavy oil resources in a demanding environment such as the UKCS.

Finally, the potential for future heavy oil developments is discussed. The scope for IOR technology to increase reserves in heavy oil fields on production by waterflood, or to improve the economics of currently sub-economic fields, is reviewed, focusing on advanced well technology, downhole separation, thermal techniques and conformance control methods.

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