Underground resources: natural gas — SoMdNews.com

Miles beneath Southern Maryland’s water table, another valuable and ancient resource lies hidden in the rock: 240-million-year-old natural gas basins.

Although not as substantial as the enormous Marcellus Shale formation underneath Pennsylvania and Western Maryland, the Taylorsville Basin has 1.064 trillion cubic feet of gas, the U.S. Geological Survey has estimated. The Marcellus has 84 trillion.

The Taylorsville basin goes through Virginia, much of central and south Charles County, northern St. Mary’s and northern Calvert. Additionally, there is a supply of gas in the Delmarva basins. The Delmarva basins are several long, skinny basins, one of which is under southern St. Mary’s County and Calvert County and reaches across the Eastern Shore into Delaware.

The Marcellus Shale formation was created about 390 million years ago and took 20 million years to form, said Jim Coleman, research geologist for the USGS. Marcellus was formed at the same time as the Appalachian mountains as continents came together. The Taylorsville basin and the Delmarva basins were created by the expansion of the earth’s crust, Coleman said.

Marcellus Shale and the gas deposits under Southern Maryland are equally accessible, depending on the various state regulations, roadwork and waterways, Coleman said.

The potential for hydraulic fracturing — called fracking, a process in which water mixed with chemicals and sand is injected deep into the formation to force natural gas to the surface — in Western Maryland prompted Gov. Martin O’Malley (D) to issue an executive order, the Marcellus Shale Safe Drilling Initiative, in 2011, which mandated the formation of the Governor’s Shale Advisory Commission and multiple state reports on the impacts of fracking and recommended best practices. Although there is a moratorium on fracking in Maryland, the potential and possibility for the resources available in the state have some concerned about how the process could affect the lives of Marylanders, by the state’s analysis of fracking in Western Maryland and in Southern Maryland as well.

“Water and chemicals into the earth is a permanent change in the nature of the land,” said Bonnie Bick, conservation chairwoman of the Southern Maryland Sierra Club.

How they do it

Although fracking has been done for decades, relatively new technology was developed for the oil and gas industry to dig deeper than ever before in the early 2000s — and horizontally — said Jorge Aguilar, Southern region director for Food and Water Watch.

Horizontal fracking means only one well has to be drilled to frack in multiple directions, said Drew Cobbs, executive director for the Maryland Petroleum Council. Horizontal fracking has less effect on the surface, as strictly vertical fracking causes a “Swiss cheese” effect.

Before, drilling could only go 2 to 5 miles underground, but the new technology allowed depths of about 25 miles, Aguilar said.

Each frack is done a section at a time, forcing chemicals, sand and water miles under the ground. The chemicals include benzyne and hydrochloric acid, Aguilar said, but Cobbs said the solution injected into the ground is mostly water, and the well casings are designed to protect the harmful chemicals from infiltrating into the groundwater supply.

The objective of fracking is to inject the sand and water under very high pressure to break the rock, Coleman said.

The fracking itself happens in a relatively short period of time, and then the well can produce for years. As the process is so new, it’s not yet known what the average production length is, Cobbs said.

An executive order and its effect

via Underground resources: natural gas — SoMdNews.com.