Drifting Cement Plugs for Geothermal Wells

Abstract

Lost of circulation while drilling a Geothermal well is very common, because typically geothermal formations are highly fractured or poorly consolidated; these conditions inherently lead to lost circulation. These potential ‘thief’ zones may allow drilling fluid (and later, casing cement slurry) to enter the formation instead of circulating back to surface When losses occur, lost circulation material is typically applied first, followed by cement plugs. Lost circulation cement plugs are used to isolate the well bore from highly porous or fractured zones that are under-pressured. Cement plugs may be used to seal lost circulation zones, allowing drilling to continue through and below the loss zone with good returns to surface. Innovative drift plug technologies may be used in place of conventional balanced plug methods, achieving better results in severe loss zones.