Faulty shale-gas wells contaminate water, study finds

Poorly constructed shale gas wells, not hydraulic fracturing, are to blame for contaminated water in Pennsylvania and Texas, says a study by scientists at Duke University and four other schools.

The study was published Monday in the Proceedings of the National Academy of Sciences.

Researchers analyzed the gas content of more than 130 drinking water wells over the Marcellus shale formation in Pennsylvania and Texas' Barnett shale. They found contamination in eight clusters of wells. 

Hydraulic fracturing extracts gas from deep underground. The suspicion has been that methane -- the main component of natural gas -- from fracking or horizontal drilling had migrated up into drinking water aquifers.

The new study appears to rule that out. Instead it found, in four contaminated clusters, that the methane leaked at shallow depths from faulty rings of cement around gas-well shafts. Three more clusters suggested methane leaked through bad well casings.

While drilling has contaminated water, the scientists say, most of the causes can be prevented.

The researchers used noble gases such as helium to trace methane emissions because they mix with natural gas but aren't affected by microbes or oxidation. Measuring the noble gases determined the source of the methane and how it reaches drinking water aquifers. 

Scientists from Duke, Ohio State University, Stanford University, Dartmouth College and the University of Rochester took part in the peer-reviewed study. Funding came from the National Science Foundation and Duke's Nicholas School of the Environment.

Opposition forming to Atlantic Coast Pipeline

Forces against the natural gas pipeline from West Virginia to Eastern North Carolina, announced last week, are quickly mustering.

A coalition of 22 conservation groups have formed the Allegheny-Blue Ridge Alliance. The groups say the pipeline route would disrupt ecologically sensitive areas, including parts of the Monongahela and George Washington national forests in West Virginia and Virginia.

The route would cross karst topography formed by soluble rocks such as limestone that form underground drainage systems, the alliance says, placing water supplies at risk.

Supervisors in Nelson County, Va., which includes part of the George Washington forest, passed a resolution opposing the pipeline on Tuesday.

Duke Energy and Charlotte's Piedmont Natural Gas, which solicited proposals for the $5 billion line, last week said Richmond-based Dominion Resources would build and operate it. The line, which needs federal approval, would tap gas deposits in the Marcellus and Utica shale basins.

The 42-inch diameter pipeline in West Virginia and Virginia would require a construction right-of-way 125 feet wide and a permanent easement 75 feet wide, Dominion says. In North Carolina, a smaller 36-inch pipe would need rights-of-way 110 feet and 50 feet wide.

Dominion says it expects to complete the route planning by December, with construction of the line in 2017 and 2018.

Open houses will start Monday at points along the pipeline route in all three states.

The other end of that new gas pipeline

Remember the news, a couple of days ago, that Duke Energy and Piedmont Natural Gas will partner on a new natural gas pipeline into Eastern North Carolina?

The Energy Information Administration published a chart today that illustrates the rich shale-gas reserves the Atlantic Coast Pipeline would tap. Pay special attention to the vast Marcellus basin in green. Gas would also come from the much smaller Utica shale, in red.

Hydraulic fracturing -- fracking -- and horizontal drilling explain the explosion in production from shale reserves. The controversial drilling techniques also raise questions about the potential for groundwater contamination, overuse of water supplies, wastewater disposal and the impact of fracking chemicals.

While the pipeline would deliver gas from several states away, the fracking debate is upon us too. Hearings began last month on North Carolina's version of fracking rules, and legislators decided that permits could be issued next spring.