The initial development plan for Clipper and Barque 'core' areas in the Southern North Sea, Sole Pit Basin called for conventional wells to intersect fissured zones wherever possible and where no open fissures were encountered, connection would be attempted via massive hydraulic, sand propped fracturing.

Since drilling began in 1988 the plan has benefited from a number of new developments:

-Improvements have been made to the design and placement techniques of Massive Hydraulic Stimulation.

-A new Borehole Televiewer that works in oil-based mud is providing information on the fissure type, orientation and density, impacting on the placement and design of later wells.

-Dune slip-face sands have been identified which enable direct production from the matrix, without hydraulic stimulation.

-Production results of highly successful, but now abandoned appraisal wells have been replicated by a technique named 'cloning'.

-The application of horizontal drainage has been very successfully tested and will be extensively utilized in both fields.

-Subtle features identified using 3D seismic derived attribute maps have explained the extent and distribution of the different free water levels.

-Well completion techniques that do not incorporate a cemented liner are being investigated.

These developments have been made possible by close co-operation across the Petroleum Engineering disciplines organized into a small integrated team.