EASTERN OVERTHRUST LOWER DEVONIAN GAS EXPLORATION PAYS OFF

G. Alan Petzet Exploration Editor Two new Lower Devonian wildcats are under way in West Virginia along the Eastern Overthrust Belt. Exploration in recent years has resulted in several gas discoveries in the Huntersville, Oriskany, and Helderberg formations of Lower Devonian age. One of the most recent wildcats in the play is Quaker State Corp., Belpre, Ohio, 1 Watson Unit, in Portland district, Oakland quadrangle, in Preston County, W. Va.

Nov. 5, 1990

3 min read

G. Alan Petzet
Exploration Editor

Two new Lower Devonian wildcats are under way in West Virginia along the Eastern Overthrust Belt.

Exploration in recent years has resulted in several gas discoveries in the Huntersville, Oriskany, and Helderberg formations of Lower Devonian age.

One of the most recent wildcats in the play is Quaker State Corp., Belpre, Ohio, 1 Watson Unit, in Portland district, Oakland quadrangle, in Preston County, W. Va.

Projected depth is 8,000 ft in Helderberg. Drill site is about 5 miles northeast of Terra Alta field, a Huntersville and Oriskany gas producing area, Petroleum Information Corp., Denver, reports.

About 60 miles south in Pendleton County, W. Va., CNG Development Co., Pittsburgh, has drilled 3983 Bennett, in Circleville district, Spruce Knob quadrangle.

In late October CNG was running logs at total depth of 8,440 ft. Original projected depth was 7,900 ft or Oriskany.

The 3983 Bennett is a confirmation well just north of CNG's 1 Raines, a not yet named Pendleton County discovery completed earlier this year. CAOF was 1.38 MMcfd of gas from Oriskany.

Well site is 25 miles southeast of Elkins, W. Va., and about 8 miles northeast of Thornwood field, a Huntersville and Oriskany area.

Operators have drilled a large number of Lower Devonian wells along the Appalachian Front in recent years.

They appear to be finding the right combination of structure and reservoir properties, such as fracture porosity, in Oriskany, says Lee Avery, a petroleum geologist with the West Virginia Geological & Economic Survey in Morgantown, W. Va.

RECENT EXPLORATION

Exploration in this area of the Appalachian basin has met with varying degrees of success year to year since discovery of Oriskany gas at Keyser field in 1979 drew attention to Eastern Overthrust potential.

The three Lower Devonian formations have been targets in wells on both sides of the Allegheny mountain front, although Oriskany is almost always the primary target and very few wells produce from Helderberg.

Columbia Natural Resources Inc. opened Helderberg pay in Jordan Run field, Grant County, in 1989 at 21705 Berg.

CAOFs were 62 Mcfd from the Corriganville member of Helderberg at 8,461-8,548 ft and 3.34 MMcfd from Oriskany at 7,991-8,120 ft.

In Tucker County, Excel Energy Inc. in 1989 completed a three zone Lower Devonian producer, E-70 John Owens, in Etam field.

Combined CAOF was 592 Mcfd from Huntersville at 4,888 5,025 ft, Oriskany at 5,059-5,140 ft, and Helderberg at 5,140-5,205 ft.

Berea Oil & Gas Corp. in 1987 discovered a new field in Preston County, along the Maryland-West Virginia line east of Terra Alta field. Its 1 Sheehan Unit, in Union district, Table Rock quadrangle, had a CAOF of 1.9 MMcfd of gas from Huntersville at 5,918-60 ft and Oriskany at 6,065-150 ft. No further work has occurred, and the field is unnamed.

Further west of the mountain front in northeastern Randolph County, CNG has drilled several wells in recent years in Bowden field, where Oriskany and Huntersville produce gas.

One well in the field, 3571 USA, was plugged earlier this year after being drilled to 11,000 ft in Lower Silurian Tuscarora sandstone.

Overthrust Belt exploration in far eastern West Virginia represents only a small part of total drilling in the state but geologically is among the most interesting-and risky work going on there.