OILFIELD DRILLING AND WELL COMPLETION PRACTICES TO INVESTIGATE THE HYDROCARBON POTENTIAL OF THE RESERVOIRS: A CASE TUDY OF ATLAS WILDCAT WELL 25/5-7 IN THE NORTH SEA

Abstract

This study focuses on oilfield drilling practices, well construction and completion with particular reference to exploration of Atlas wildcat well 25/5-7. Located on the North Sea to investigate the hydrocarbon potential of the Brent reservoirs, Stratford and tertiary formations. This well was spudded up with semisubmersible ocean vanguard and drilled to total depth at 3045m. The well was drilled with sea water and mud with higher rheology to sweeps down to 1160m with oil based mud from 1160m to TD. The results shows that all potential tertiary reservoir were found water based, Stratford was found water wet while the Brent found gas bearing reservoirs, Gas condensate were taken at 2708m and 2689m. The well was drilled for 61 days, however the rig experienced a power shutdown while drilling and opening up tight spots at 438m and was on repair for 5 days from 31 August until September 2010.