Post on 15-Feb-2020
transcript
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