DEP Monitors Stray Gas Remediation in Bradford County Requires
Chesapeake to Eliminate Gas Migration
Chesapeake Commits to Evaluate, Remediate All PA Wells to Conform
with Improved Casing Regulations
PA-DEP
Release
17 September 2010
COMMONWEALTH OF PENNSYLVANIA
Dept. of Environmental Protection
Commonwealth News Bureau
Room 308, Main Capitol Building
Harrisburg PA., 17120
FOR IMMEDIATE RELEASE
CONTACT: Tom Rathbun, Department of Environmental Protection
717-787-1323
HARRISBURG -- While the Department of Environmental Protection
continues to monitor Chesapeake Energy’s progress in remediating stray
methane gas in Wilmot Township, Bradford County, the agency announced
today that it has directed the company to take steps to prevent similar
situations from occurring elsewhere in the region.
On Sept. 2, DEP received reports of bubbling water on the Susquehanna
River. DEP and Chesapeake believe the culprit is gas migrating from six
wells that are located on three well pads on the “Welles property,”
which is approximately two to three miles northwest of the river.
“Ventilation systems have been installed at six private water
wells. Water has been provided to the three affected homes and
Chesapeake is evaluating and remediating each of its well bores within
a four-and-a-half-mile radius of the gas migration, which is
essential,” said DEP Secretary John Hanger.
DEP sampled six private water wells affected by the migration for
compounds associated with natural gas drilling. Their analysis found
methane levels in the water wells that fluctuated between non-detect
and 4.4 percent, possibly as a result of barometric pressure in the
atmosphere. No stray gas has been detected in the homes served by the
water wells. DEP also found:
• Methane concentrations ranging from 2.16 milligrams per liter and
55.8 mg/L.
• The water met the drinking water standards established for barium,
chloride and total dissolved solids.
• Three wells exceeded the iron limit of 0.3 mg/L and all six wells
exceeded the 0.05 mg/L limit for manganese.
The iron and manganese limits are secondary limits, which mean that the
limits are established to prevent taste and odor issues.
DEP and Chesapeake individually sampled isotopic readings from the gas,
which could help pinpoint which well is responsible for the gas
migration. DEP expects its isotopic analysis to be complete next week
while Chesapeake’s is expected sooner.
To help prevent against future migration issues, Hanger said DEP
directed Chesapeake to evaluate each of its 171 wells in Pennsylvania
that used the well casing procedures used in the six Wilmot Township
wells—a procedure that was used exclusively in northeast Pennsylvania.
Well casings are installed in a well bore to act as a barrier to the
rock formations and maintain the well’s integrity.
To do so, the company is using equipment sensitive to sound and
temperature. When the equipment finds an anomaly, the company is to
correct it immediately by injecting cement behind the casing that seals
off the formation, eliminating the route for gas to migrate.
Once the remediation work is performed, it will take up to two weeks to
determine if it was successful, although it may take longer for the
stray gas to dissipate.
The Welles property wells were drilled between December 2009 and March
2010, but have not been fractured, or “fracked,” and are not yet
producing gas from the Marcellus Shale formation, leading the agency to
believe that any stray gas migrating from these wells is from a more
shallow formation.
On Sept. 9, DEP issued Chesapeake a notice of violation for failing to
prevent gas migration to fresh ground water and for allowing an
unpermitted natural gas discharge into the state’s waters. DEP will
determine future enforcement actions based in part on the speed with
which Chesapeake eliminates the migrating gas.
“This situation perfectly illustrates the problem DEP is addressing
through the improved well construction standards we have finalized,”
said Hanger. “Chesapeake has assured me that all wells drilled by
Chesapeake after July 31 conform to the regulations that the
Environmental Quality Board will consider on Oct. 12.”
If approved by the EQB, the Independent Regulatory Review Commission is
expected to vote on the regulations in November.
For more information, visit http://www.depweb.state.pa.us.