Abstract

The depositional rock-pore network in the Cretaceous Frontier Formation of the northern Moxa Arch, southwest Wyoming, is over-printed by a complex diagenetic sequence; rock quality and formation damage potential can vary significantly from well to well. Although it has long been recognized that the Second Frontier is an easily damaged gas reservoir, it has been difficult to document the degree that damage actually affects production. A case study of a well drilled by Getty Oil Company in 1984 provides the documentation that formation damage can result in a 59% reduction in flow rate.

Rock-pore properties of Frontier pay zones may be studied petrologically so that drilling and completion methods can be designed to minimize formation damage, yielding better than average flow rates. Many leases with good Frontier gas potential may have been overlooked in the past due to incompatible completions of the easily damaged Frontier reservoir in offsetting wells.