Drilling and Completing the Marcellus Shale of the Appalachian Basin - One Operator’s Story
Geologic variations of the Marcellus Shale in the Appalachian Basin directly impact the outcome of the drilling and completion methods employed. Abnormal pressure, faults and fractures, presence of barriers to hydraulic fractures, and brittleness of the shale are a few of the factors impacting the results of Marcellus Shale wells.
Numerous operators drilling horizontal wells in the organic rich Marcellus Shale of northern West Virginia and southwestern Pennsylvania have encountered difficulties resulting in long delays and expensive wells. Economic viability of Marcellus Shale development will depend on minimizing drilling issues and enhancing completion techniques.
Due to the drilling problems operators are facing, other, less problematic horizons are being targeted for drilling to unlock the potential from the Marcellus Shale. The grey shales and limestones of the Hamilton Group immediately overlying the Marcellus can provide wellbore stability for drilling the laterals as well as act as a brittle zone to aid in initiating hydraulic fractures during completion. Hydraulic fractures can propagate down into the Marcellus, if the wellpath is close enough to the top of the Marcellus and the structure is not complicated by large fault networks.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009