Shearwater Field, managing changing uncertainties through field life

Development of the Shearwater structure, a deep gas-condensate accumulation in the HPHT region of the UKCS, began in 1997 with the initial of development drilling and construction of topside facilities. Field sanction was based on an understanding and modelling of key subsurface uncertainties. Development experience since that date has tested that initial subsurface view and helped constrain many of the initial pre-development uncertainties. The displayed core illustrates several of the pre-development uncertainties: (1) depositional and diagenetic controls on reservoir quality potential vertical compartmentalisation by dolomite cements; (2) potential lateral compartmentalisation by sealing sand-sand faults; (3) potential pore volume reduction by early oil stain.