Trenton-Black River Play Expands

‘The Rocks Are Everywhere’

For the first time in a long time, an exploration play in the Appalachian Basin is sparking the interest and imagination of oil companies around the country, thanks largely to advances in seismic operations, drilling technology and geologists’ understanding of a complex play.

The productive zone lies in the formations of the Ordovician-age Trenton-Black River, which started the John D. Rockefeller empire over 100 years ago and is once again padding the bottom lines of Appalachian Basin operators.

Charleston (W.Va.)-based Columbia Natural Resources touched off the recent frenzy of activity there when the firm brought in some impressive wells on its acreage in New York’s Finger Lakes region.

This was unexpected. The Trenton-Black River has not been a major target in the Appalachian Basin because the zone is deeper than traditional producing reservoirs in the basin.

But the firm’s geoscientists had been studying the Trenton-Black River for years - and all that work finally has come to fruition.

Äolumbia’s success with its basin-wide deep drilling program is proving that the Appalachian Basin still holds tremendous potential - and the lower 10,000 feet of sediment are virtually untested.

“This is the most exciting thing to happen to the Appalachian Basin since the early 1950s,” said Alan Fairman, business manager with Fairman Drilling in DuBois, Pa. “We are even starting to get inquiries from large independents based in the Southwest.”

Kathleen Sanford, with the New York State Department of Environmental Conservation’s Division of Mineral Resources, agreed.

“We hear reports of dozens of landmen in New York, and a recent state lease sale seems to bear out those reports,” she said. “In a 1999 state lease sale we had record bids as high as $312 per acre for some acreage in Schuyler County - our previous high bids were in the $60 to $70 range. That lease sale was held just a couple of weeks after a successful discovery well happened in Steuben County, and landmen who were in Wyoming and Louisiana at that time tell us they heard about the well.”

Currently the state is preparing another lease sale, and 23,000 acres have been nominated.

“That’s a tremendous amount of acreage to be nominated in New York, and we are expecting the same level of interest that we saw at the 1999 sale,” Sanford said. “All 23,000 acres nominated are in the Trenton-Black River play area.”

To be put on a mailing list to receive information about the upcoming sale, email your name and address to dmnog@gw.dec.state.ny.us.

Good Indications

Today four fields are producing deep gas from the Trenton-Black River in Steuben and Chemung counties of southwestern New York, and the wells in these new fields, according to those involved, have been phenomenal.

Columbia in 1999 had expanded its Trenton-Black River program and made a discovery in Roane County, W.Va., that was geologically similar to its wells in New York.

Richard Beardsley, vice president of geology and geophysics with Columbia, said the company’s last two wells in West Virginia were the largest wells in the northeast United States in terms of open flow rates.

In fact, the West Virginia discovery well - drilled to 10,300 feet on Columbia’s Vineyard Ridge area - demonstrated an open-flow rate estimated at approximately 50 million cubic feet of gas a day.

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For the first time in a long time, an exploration play in the Appalachian Basin is sparking the interest and imagination of oil companies around the country, thanks largely to advances in seismic operations, drilling technology and geologists’ understanding of a complex play.

The productive zone lies in the formations of the Ordovician-age Trenton-Black River, which started the John D. Rockefeller empire over 100 years ago and is once again padding the bottom lines of Appalachian Basin operators.

Charleston (W.Va.)-based Columbia Natural Resources touched off the recent frenzy of activity there when the firm brought in some impressive wells on its acreage in New York’s Finger Lakes region.

This was unexpected. The Trenton-Black River has not been a major target in the Appalachian Basin because the zone is deeper than traditional producing reservoirs in the basin.

But the firm’s geoscientists had been studying the Trenton-Black River for years - and all that work finally has come to fruition.

Äolumbia’s success with its basin-wide deep drilling program is proving that the Appalachian Basin still holds tremendous potential - and the lower 10,000 feet of sediment are virtually untested.

“This is the most exciting thing to happen to the Appalachian Basin since the early 1950s,” said Alan Fairman, business manager with Fairman Drilling in DuBois, Pa. “We are even starting to get inquiries from large independents based in the Southwest.”

Kathleen Sanford, with the New York State Department of Environmental Conservation’s Division of Mineral Resources, agreed.

“We hear reports of dozens of landmen in New York, and a recent state lease sale seems to bear out those reports,” she said. “In a 1999 state lease sale we had record bids as high as $312 per acre for some acreage in Schuyler County - our previous high bids were in the $60 to $70 range. That lease sale was held just a couple of weeks after a successful discovery well happened in Steuben County, and landmen who were in Wyoming and Louisiana at that time tell us they heard about the well.”

Currently the state is preparing another lease sale, and 23,000 acres have been nominated.

“That’s a tremendous amount of acreage to be nominated in New York, and we are expecting the same level of interest that we saw at the 1999 sale,” Sanford said. “All 23,000 acres nominated are in the Trenton-Black River play area.”

To be put on a mailing list to receive information about the upcoming sale, email your name and address to dmnog@gw.dec.state.ny.us.

Good Indications

Today four fields are producing deep gas from the Trenton-Black River in Steuben and Chemung counties of southwestern New York, and the wells in these new fields, according to those involved, have been phenomenal.

Columbia in 1999 had expanded its Trenton-Black River program and made a discovery in Roane County, W.Va., that was geologically similar to its wells in New York.

Richard Beardsley, vice president of geology and geophysics with Columbia, said the company’s last two wells in West Virginia were the largest wells in the northeast United States in terms of open flow rates.

In fact, the West Virginia discovery well - drilled to 10,300 feet on Columbia’s Vineyard Ridge area - demonstrated an open-flow rate estimated at approximately 50 million cubic feet of gas a day.

Bottom hole pressures initially gauged at 6,600 pounds per square inch - highly unusual for typical Appalachian Basin production - were sustained through the first month of production.

The second well in the Cottontree Field posted a natural flow from about 9,600 feet and was operationally similar to the discovery well.

Columbia has completed a five-mile, eight-inch gathering line connecting the new field to Columbia Gas Transmission’s nearby high-pressure interstate pipeline. Since the gathering line was completed the firm is averaging about 7.4 million cubic feet of gas a day from the field.

Today Columbia is drilling its fifth well in the Cottontree Field. Beardsley said the West Virginia prospect is more than 20 years old.

“Advances in drilling technology that now allow us to drill to 10,000 feet and deeper at a reasonable cost, combined with the successes in the Trenton-Black River in New York, brought this West Virginia prospect to the forefront,” he said.

These recent wells aren’t the first Trenton-Black River wells in the state.

“The first Trenton-Black River well was drilled in 1936 and burned the rig to the ground,” he said, chuckling, “a good indication hydrocarbons were present.”

Patience Pays Off

The New York activity that touched off the interest in the Trenton-Black River has been a long time coming as well.

Columbia first began studying the Ordovician formations in the early 1970s, when the firm was looking for Devonian reefs in New York and acquired about 900 miles of seismic data. Scientists didn’t confine themselves to Devonian targets, however, and looked at additional horizons on the seismic.

“At that time we also looked at old wells that had penetrated what we believed were hydrothermal reservoirs,” Beardsley said. “We modeled this area after what we saw in western Ontario, where some old fields dating back to 1917 produce from hydrothermal reservoirs in the Trenton-Black River.

“That production in Ontario, coupled with the Lima-Indiana Field, which started the seven sisters for John Rockefeller, certainly indicated the Trenton-Black River formations were worth examining in the Appalachian Basin,” he added. “Our work and samples we saw indicated that a deep-seated heat source generated a hydrothermal cell that provided mobilization of magnesium rich waters deep in the reservoir, which created hydrothermal cave systems.”

The one-and-a-half-billion-year-old Greenvillian Orogeny likely became the fundamental route for all the deep-seated basin features found in this play area.

“Basically, we are now looking at areas where major separation and rotation of the basin created networks of faults and fractures that provided conduits for the hot water,” he said.

Columbia’s first test of the Trenton-Black River in 1980 was a dry hole.

“(But) we took the information gleaned from that well and developed geologic models for the play,” Beardsley said.

The first Trenton-Black River discovery in New York came in 1986 at Columbia’s Gloades Corners Field, but a combination of industry and corporate problems added 10 years before that first discovery came on line.

“It was difficult to generate management interest for a new play concept in a region isolated from pipelines, but by the mid-1990s we revisited the area and drilled a successful offset well one mile from the Glodes Corner discovery,” Beardsley said.

The company then built a pipeline to service the region, and that, according to Beardsley, “was the key to expanding the drilling program.”

Today Columbia has made 10 new Trenton-Black River field discoveries in New York - seven solo and three through joint ventures.

Seismic Clarity

Columbia’s success and new seismic studies sparked several additional operators to join the play.

Fairman Drilling and partner East Resources of Pittsburgh currently have about 30,000 acres under lease in West Virginia and are continuing to expand their holdings. The firms were drilling their sixth Trenton-Black River well at year-end and this year plan to drill about 18 wells in south central New York.

By mid-year the partners plan to begin testing acreage in West Virginia, according to Alan Fairman.

East Resources first approached Fairman Drilling in early 1998 about establishing a joint venture to purchase regional seismic and develop some prospects in the play. Reports from the firms’ geologic consultants, Orion Resources Consulting in London, Ontario, indicated some very promising potential.

Next, the two companies shot about 40 miles of additional seismic to identify drill sites. At the same time the firms began acquiring acreage, and by the summer of 1999 had about 180,000 acres under lease.

Today the joint venture has acquired over 150 miles of new seismic and has 250,000 acres, Fairman said.

Fairman and East Resources drilled their first well in March 1999 and made a discovery at the No.1 Broz in Chemung County. The well was drilled to 9,303 feet and initial open flow estimates were in excess of 15 million cubic feet of gas a day. That well will be going on line later this year.

A dry hole just north of the discovery well followed, but last summer the firms’ third test, the No. 1 Whiteman, was a success. That well, sited seven miles west of the Broz, was drilled to the Black River at 9,511 feet, encountering natural gas shows of over 12 million cubic feet of gas a day.

The joint venture’s fourth well was drilled seven miles north of the Whiteman well in Schuyler County on state lands. The SRA 2 No. 1 well went to 8,770 feet and found a natural gas flow of over 30 million cubic feet of gas a day.

Last fall the two companies completed a one-mile offset to the Broz that flowed an estimated 15 million cubic feet of gas daily. Currently the joint venture is sidetracking its sixth well after drilling into an unproductive section of the Black River at 10,400 feet.

By mid-year three of East Resources and Fairman Drilling’s wells are expected to be on production.

“Following Columbia’s success, this play was appealing to our company because we had the capabilities to drill to these depths, and due to availability of acreage in New York,” Fairman said.

“Also, Orion Resources had experience with the Trenton-Black River in Ontario, and the firm’s geologists said the features on our seismic were far more pronounced than what they see in Ontario.”

The economics of the play is an obvious plus.

“Our wells have cost from $850,000 to $1 million to drill to about 10,000 feet, but once they go on line we could have situations where we will pay out the wells in just a couple of months,” Fairman said. “When was the last time you saw that in the Appalachian Basin?

“These wells are not typical Appalachian Basin discoveries. The potential for large production volumes is significant - the formation we are drilling into is 350 to 400 feet thick, but we have only drilled into the top 30 to 40 feet because of the large amounts of gas we have coming out the flow line.

“That’s a nice problem to have.”

Pennsylvania General Energy is the third major player in the New York Trenton-Black River play. Late last year the firm was drilling its fifth Trenton-Black River well after netting four-for-four successful wells.

Analogous Possibilities

Generally the Black River is a shallow-water carbonate overlain by the deeper water Trenton formation, which is an argillaceous limestone.

The productive zones in these Ordovician carbonates are centered on fault or fracture systems. The carbonates have been dolomitized by hot, magnesium-rich water tracking up the faults and fractures, said Robert Trevail, with Orion Resources.

Seismic has been important to recent successes, and in general operators are looking for:

  • Structural depressions over the dolomitized zone.
  • Vertical displacement of the underlying Precambrian basement surface.
  • A change in character on seismic records within the dolomitized zone.

Non-porous limestones typically bound the reservoirs.

“Unlike traditional plays where you look for highs on the seismic, we are looking for lows - slumps that indicate a dolomitized zone,” Trevail said.

Now that geologists have a better understanding of the properties of productive Trenton-Black River plays the Appalachian Basin - as well as the entire eastern United States - could see a boom in activity searching for analogous settings.

“The Trenton-Black River formations are pervasive over an enormous area of the north and eastern regions of the country,” said Brian Keith of the Indiana Geological Survey. “The rocks are everywhere - the key is finding the fracture systems that allow these dolomitized reservoirs,”

Fairman agreed.

“When you look at a map you can see that the Trenton-Black River runs all the way from the St. Lawrence Seaway to Kentucky,” Fairman said. “With a better geologic understanding and improvements in seismic technology, there’s no reason to think that analogous plays won’t be found in other regions.”

And that’s good news for operators in the northeast where big, exciting exploration plays don’t come along every day - or every decade, for that matter.

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