Extract

This ‘Field management’ section contains 13 papers focusing specifically on two areas of field evaluation:

• appraisal of complex offshore discoveries;

• management and review of developed fields, both offshore and onshore.

In addition, some 13 field case studies are presented within other sections of these volumes, along with many other briefer references to fields within NW Europe, particularly in the North Sea area (Table 1).

A number of themes can be recognized which reflect recent developments within the industry. The first trend which we note is the industry’s ability to contain risk through better understanding of the technical problems, with improved technology able to provide greater flexibility in development planning. Technical disciplines are communicating better and shorter management chains bring the decision-makers closer to the issues.

Several papers describe development prospects whose appraisal history has been prolonged by contradictory delineation well results giving wild fluctuations in anticipated reserves. Other prospects were intially believed to be too small, complex, or poorly productive to warrant development, and two papers consider the consequences of inadequate appraisal. A typical example of fluctuating reserve estimates is described in ‘The evolution of a fractured chalk reservoir—Machar Oil Field, UK North Sea’ by Foster and Rattey. This field was discovered in 1976, but is only now ready for development following a long appraisal history during which the difficulties in understanding the reservoir distribution in a complex chalk system were overcome. High pressure, poor seismic resolution, structural complexities and ill-defined reservoir stratigraphy combine to provide major reserve uncertainties . . .