Oct. 24--A three-dimensional map of the Marcellus Shale underneath eastern Westmoreland County, including Keystone State Park, will be produced in the coming months to help two drilling companies locate the best spots for gas wells.

A public meeting was held at the park Friday night to help explain the mapping process of the Marcellus Formation, which contains a natural gas reserve energy companies are eager to tap.

The map is being produced by Oklahoma-based McDonald Land Services and Dawson Geophysical Company of Texas on behalf of Rex Energy and the Williams Production Appalachia, two energy exploration firms.

The area to be mapped is 42 square miles extending from the southern edge of New Alexandria to Route 217 near Brenizer and from an area just west of Latrobe to the ridge just east of Derry, said Rod White, land representative for McDonald.

Within that area is the 1,200-acre Keystone State Park, which except for a 500-foot buffer around the lake, will be mapped.

Property owners have been notified of the project and are being asked for permission to conduct the mapping, White said.

Surveyors are just starting to begin mapping the area, taking note of any utility lines, wells, buildings and other obstructions that need to be avoided in the process.

Drill trucks will then move in to drill approximately 4,100 holes over the area. Each hole is 2 inches in diameter and 20 feet deep. Inside each hole will be a 2.2 pound charge.

As the charges are set off, they will send energy waves into the ground. Those waves will bounce off the Marcellus Shale and back to the surface, where a series of devices called geophones will be implanted.

The geophones will record data, which will be later used to build the 3-D computerized map.

The drilling process should begin around the beginning to middle of December and be completed by February. Crews will work from west to east and should be finished inside the park boundaries sometime in January.

"Our objective is to get in and get out of the state park as quickly and as cleanly as we can and leave the smallest footprint possible," White said.

The park has shallow gas wells drilled, but none in the deeper Marcellus Shale, said manager Kristian Baker.

The park has no choice but to allow the mapping because Rex Energy owns the mineral rights lease. The lease has changed hands over the years but goes back to the days before the park was founded when the property was owned by Keystone Coal and Coke Company.

And while park officials do not have a legal choice in the matter, Baker said they are making the best of the situation.

The companies have agreed to share information with the park based on their surveying. The Department of Conservation and Natural Resources has been working on producing computerized maps of each park.

The GPS information produced by the surveying will enable that to be done at Keystone without using park employees, Baker said.

While some brush and vegetation will be disturbed during the mapping process, Baker believes it won't be noticeable in six months to a year after a growing season. And with the process occurring in the fall and winter, it won't impact as many park users, he said.

It will take about six to nine months after the on-site mapping is complete for the data to be finalized and handed over to the well drilling companies, who will use the information to determine where the best prospects for natural gas are.

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