Formation Damage Prevention.
Formation damage is often viewed as problem that occurs as a natural part of drilling to be addressed by expensive treatments during the completion phase of well construction. This defeatist approach is characteristic of turnkey drilling operations where drilling success is measured solely on cost to reach the target well depth. In many cases inexpensive methods to prevent formation damage when drilling are overlooked, resulting in wells performing far below their potential. Preventing formation damage in sandstone during the drilling process can usually be achieved by adjusting particle size distribution in drilling fluid to bridge the largest pore connections and by avoiding chemistry incompatible with the reservoir in both drilling and completion fluids. In carbonate rocks with more variable pore systems the situation is more complex. The strategies used to prevent formation damage in sandstone apply to some, but not all classes of limestone. This talk discusses formation damage issues when drilling reservoir formations including: recognition of formation damage problems, pore sizes and particle size strategies, and maximizing clean-up effectiveness during completion. Geologists should take the lead in assessing pore size and reservoir characteristics needed for designing non-damaging drilling and completion systems.
AAPG Search and Discovery Article #90152©2012 AAPG Southwest Section Meeting, Fort Worth, Texas, 19-22 May 2012