Observations and Thoughts on Fault Timing and its Effects on Marcellus Horizontal well Productivity and Performance

Peter A. Sullivan and Chadwick J. Cunningham
Energy Corporation of America, Charleston WV,
[email protected], [email protected]

The boom in production from Marcellus horizontals has dramatically changed our knowledge and understanding of the Appalachian basin. More Marcellus horizontals have been drilled in the past five years in Pennsylvania and West Virginia than Oriskany and deeper wells in the previous 100 years. The large scale exploration of these older rocks has given way to new insights on the structural complexity of the basin.

The Energy Corporation of America (ECA) has been actively drilling Horizontal wells to the Marcellus in Pa and WV since 2008. The effects of fault interaction with Marcellus Production performance have evolved over the intervening 4 years and continue to evolve today.

Examples will illustrate there are 4 ages of faults and associated pitfalls and or windfalls, which ECA has encountered in our Marcellus Exploration and development activities. The ages of faults to be discussed are:

1. Early Devonian/Early Acadian (Faults that end in the Elk interval)
2. Upper Devonian/ Late Acadian (Faults that cut the Devonian Sand section but not the Big Injun or Big Lime)
3. Pennsylvanian Faults/ Early Alleghanian (Faults that have displacement on the Big Lime/Big Injun interval.)
4. Cross Strike Faults/ Late Alleghanian (Lineament type Strike Slip faults that appear to extent to the surface.)

Horizontal Marcellus drilling and completion strategies need to be adjusted around each type of fault in order to efficiently institute a field development plan.

AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012