Rising oil price and demand has led to increased effort to develop reservoirs in the North Sea that were previously considered uneconomical by major operators. The recent DTI ‘Promote’ licensing initiative has encouraged smaller oil companies to apply for exploration/appraisal acreage on a limited financial commitment basis for two years before initiating a more traditional work program.

Companies using this option to develop heavy oil reservoirs in the North Sea, many of which were discovered in the 70's, face a number of uncertainties traditionally associated with heavy oil. These include the determination of density and live oil viscosity at reservoir temperature where no clear correlation exists and the determination of reservoir properties from a limited range of historical data. In the offshore environment heavy oil developments are further complicated by the high front-end costs, limited reservoir size and uncertainty in geology and productivity. Only four of the heavy oil fields discoveries on the UK Continental Shelf (UKCS) have reached development and we review these fields to illustrate the challenges.

Many of the reservoir and fluid uncertainties can be addressed with modern logging and analysis methods and recommendations for data gathering campaigns in these environments are provided. The technological challenges of an offshore heavy oil development can be met with advances in sand control, ESP technology and EOR techniques. Combined together these solutions provide more accurate production forecasts, which help the economics of developing the resource to be better understood.

The proposed appraisal and development of a heavy oil field situated in Block 9/3b is used as a case study to highlight the challenges faced by operators in the development of heavy oil fields in the North Sea. Re-evaluation of historical data was used to develop a range of production forecasts that fully capture the potential and risk of the development.

You can access this article if you purchase or spend a download.