News Release

Framework for predicting underground rock geometry may aid coal, gas companies

Peer-Reviewed Publication

Virginia Tech

BLACKSBURG, Va., April 3, 2002—Jesse Korus, a graduate student in Virginia Tech’s Department of Geological Sciences, is developing a framework for predicting the geometry of important rock formations below ground.

Korus, along with Professor Ken Eriksson of geological sciences, is studying a unit of West Virginia rock consisting of thick and extensive sandstone bodies. The rocks are exposed along the walls of the New River Gorge. They are economically important because they contain coal, Korus said. "Sandstone also acts as a reservoir for gas," he said.

In studying the rock formations, Korus and Eriksson used electric logs from gas and oil wells. "The logs allow you to interpret whether the rocks underground consisted of sandstone or shale or coal," Korus said. Korus also did field work on the site during the summer.

He found that the sandstone bodies can be divided into two types. Those on the northwest are thinner and in huge sheets and those on the southeast are like channels. "We have interpreted the sheet-like sandstone bodies as large, paleo-fluvial drainage systems and the channel-like sandstone bodies as tributary drainage systems. There were very large rivers flowing from the northeast to the southwest—an axial fluvial (river) system with smaller southeast-northwest-flowing tributary systems connected to it. Over time, the area had various cycles of erosion and deposition in this trunk-tributary system.

"The basin in which these deposits developed was slowly subsiding, or sinking, at the same time of erosion and deposition, Korus said. The slow subsidence was asymmetrical, with the southeast side sinking faster than the northwest side. The cycles of erosion and deposition superimposed on the subsidence contributed to the sandstone bodies’ being large sheets and the fact that coal was preserved in the southeast side of the basin, Korus said.

"We interpret the cycles as being caused by the sea level rising and falling through time, and this was caused by the melting and refreezing of continental ice sheets. The basin subsidence was caused by the collision between Africa and North America during the building of Pangea," Korus said.

Oil and gas companies in West Virginia can use this study to better understand the rocks they are drilling, and the coal companies can better understand where coal will occur, Korus said. "It’s of academic interest to understand how these ice ages and the building of mountains interacted to create the rock we see today."

Korus will present his findings in Session 6, "A Stratigraphic Framework for Predicting Sandstone Body Geometry in Fluvial and Estuarine Deposits of the New River Formation, West Virginia," at 1 p.m. Wednesday, April 3, during the meeting of the North-Central and Southeastern Sections of the Geological Society of America at the Hyatt Regency Hotel in Lexington, Ky.

###

PR CONTACT: Sally Harris (540) 231-6759 slharris@vt.edu
Researcher contact: Jesse Korus can be reached at 540-231-8162 or jkorus@vt.edu.
Professor Ken Eriksson can be reached at 540-231-4680, kaeson@vt.edu


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.