HP/HT horizontal sand-control completion

The Marnock field is a retrograde gas/condensate accumulation in the U.K. c entral North Sea with a 9,123-psi bottomhole pressure and 310 degreesF bott omhole temperature. The development plan called for six horizontal wells wi th average reservoir sections 2,460 ft long. Drilling was conducted in two phases and has delivered four wells capable of the original plateau rate ex pected from six wells. Main,well-completion challenges were installing down hole sand control in a horizontal well, flowback of 1.9 specific gravity (S G) drilling mud through sand screens, and use of an isolation valve to allo w the upper completion to be installed underbalanced. The four weds complet ed are capable of delivering sand-free production with individual well rate s as much as 120 MMscf/D.