Geology of the Marcellus Shale

Katharine Lee AvaryWest Virginia Geological & Economic Survey

304/594-2331avary@geosrv.wvnet.edu

www.wvgs.wvnet.edu

The Marcellus Shale

• What is it? • Shale is a fine-grained sedimentary

rock. • The Marcellus is a particular rock unit

which is Devonian in age.

Coalbedmethane

Marcellus Shale

Trenton-Black River

Different age rocks of recent interest to oil and gas producers

Where is the Marcellus present in WV?

• It is present below the surface, at varying depths throughout much, but not all of WV.

• It is not present in extreme eastern or western WV.

• It crops out at the surface in parts of the Valley and Ridge province in eastern WV.

• It varies in thickness across WV.

Elevation of top of Onondaga Limestone, in feet

Randolph

Hardy

Kanawha

GreenbrierFayette

Grant

Preston

Raleigh

Pocahontas

Boone

Clay

Nicholas

Wayne

Roane

Logan

Mingo

Pendleton

Lewis

Webster

Braxton

Ritchie

Mason

WoodTucker

Monroe

Lincoln

Mercer

Hampshire

Wirt

Jackson

McDowell

Tyler

Wyoming

Wetzel

Gilmer

Harrison

Upshur

Cabell

Marion

Putnam

Mineral

Barbour

Monongalia

Taylor

Ohio

Summers

Berkeley

Marshall

Calhoun

Doddridge

Morgan

JeffersonPleasants

Brooke

Hancock

0

-440

0-3

900

-400

0-3

800

-420

0

-460

0

-370

0

-340

0

-3600

-3300

-4100

-290

0

-100

-310

0

-4300

-4900

-320

0

-480

0

-350

0

-450

0

-520

0

-4700

-200

0

-150

0

-5100

-300

0

-500

0

-250

0

-2600

- 280

0-2

700

-560

0

-550

0

-2400

-650

0

-230

0

-530

0

-640

0

-6000

-6100

-5400

-220

0

-5900

-6300

-500

-6200

-570

0

-5800

-400

0

-4900

-460

0-6

000

-530

0

-300

0

-5600

0

-520

0

-4900

-5000

-5000

0-340

0

-480

0

-400

0

-4100-4500

0

-450

0

-600

0

-4900

-250

0

-400

0-250

0

0

-5000

-30000

-470

0

-5000

0

-270

0

-5700

-6000

-650

0

-440

0

0

-4800

-4600

-4700

0 25 50 75 10012.5Miles

Structure Contours on top of Onondaga in feet

tfrom Cardwell, 1982

The Onondaga Limestone immediately underlies the Marcellus, so knowing the elevation of the top of the Onondaga and the surface elevation at a particular location provides a way to estimate the depth of a well drilled all the way through the Marcellus Shale.

Outcrops of Marcellus

The Marcellus is exposed at the surface in eastern WV as shown by the outcrop map. In the eastern-most counties, older rocks are exposed at the surface and the Marcellus is not present.

From 1968 state geologic map

Thickness in feet and extent of Marcellus Shale in subsurface

Marcellus not present west of this line

Area of thicker Marcellus

For Further Information:

• WV Geological & Economic Survey,http://www.wvgs.wvnet.edu/

• WV Department of Environmental Protection, Office of Oil and Gas, http://www.wvdep.org/item.cfm?ssid=23