Temporal variability of methane in domestic groundwater wells, northeastern Pennsylvania

Smith, Bert J.; Becker, Mark F.; Siegel, Donald I.

doi:10.1306/eg.01121615016

Cited by 17 publications

(7 citation statements)

References 24 publications

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“…S13 ); thus, the increases in salinity and [CH 4 ] cannot be attributed to migration of HVHF fluids from the Marcellus Formation. Fluctuations in [CH 4 ] measured previously in open-hole, drinking water wells have been linked to seasonal water table variations that change the proportions of shallow and deep groundwater entering the wells ( 44 ). Hydraulic heads ( H ) at our sites were uncorrelated with the monotonically increasing [CH 4 ].…”

Section: Resultsmentioning

confidence: 99%

Methane in groundwater before, during, and after hydraulic fracturing of the Marcellus Shale

Barth-Naftilan

Sohng

Saiers

2018

Proc. Natl. Acad. Sci. U.S.A.

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SignificanceThis study incorporates time series sampling of groundwater before, during, and after drilling, hydraulic fracturing, and initiation of shale gas production. Using monitoring wells installed next to gas well pads and above gas well laterals, previously undocumented responses to drilling and a gas well casing breach were observed, although groundwater impacts arising from the process of hydraulic fracturing were not detected. We discover considerable temporal variability in methane concentrations in deeper horizons of freshwater aquifers and attribute this to persistent shifts in aquifer recharge that influence mixing between shallow freshwater and comparatively saline and methane-rich deep groundwater. These results have implications for attribution of groundwater contamination to specific stages of shale gas development or natural processes and improving regulatory monitoring.

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Section: Resultsmentioning

confidence: 99%

Methane in groundwater before, during, and after hydraulic fracturing of the Marcellus Shale

Barth-Naftilan

Sohng

Saiers

2018

Proc. Natl. Acad. Sci. U.S.A.

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“…Once it appeared that high‐dissolved methane water wells were clustered, additional sampling was conducted in and around the cluster in order to better define it. Wells were sampled only once, but recent studies on methane variability have suggested that, although indeed variable, methane concentrations do not change by orders of magnitude in a given well (Gorody ; Loomer et al ; Molofsky et al ; Smith et al ). The sampling occurred between February and June 2014.…”

Section: Methodsmentioning

confidence: 99%

Controls on Methane Occurrences in Shallow Aquifers Overlying the Haynesville Shale Gas Field, East Texas

et al. 2017

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Understanding the source of dissolved methane in drinking-water aquifers is critical for assessing potential contributions from hydraulic fracturing in shale plays. Shallow groundwater in the Texas portion of the Haynesville Shale area (13,000 km ) was sampled (70 samples) for methane and other dissolved light alkanes. Most samples were derived from the fresh water bearing Wilcox formations and show little methane except in a localized cluster of 12 water wells (17% of total) in a approximately 30 × 30 km area in Southern Panola County with dissolved methane concentrations less than 10 mg/L. This zone of elevated methane is spatially associated with the termination of an active fault system affecting the entire sedimentary section, including the Haynesville Shale at a depth more than 3.5 km, and with shallow lignite seams of Lower Wilcox age at a depth of 100 to 230 m. The lignite spatial extension overlaps with the cluster. Gas wetness and methane isotope compositions suggest a mixed microbial and thermogenic origin with contribution from lignite beds and from deep thermogenic reservoirs that produce condensate in most of the cluster area. The pathway for methane from the lignite and deeper reservoirs is then provided by the fault system.

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“…Molofsky et al 2013;McIntosh et al 2014;Moritz et al 2015;Siegel et al 2015;Humez et al 2016), but it is also known to vary temporally (e.g. Gorody 2012; Coleman and McElreath 2012;Humez et al 2015;Smith et al 2016, Currell et al, 2017Sherwood et al, 2017; see section A1 in the Appendix for an in-depth review). Many authors in the last decade have stressed the need for long-term monitoring data of dissolved methane concentrations and isotopic composition (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Several authors (Hirsche and Mayer 2009;Coleman and McElreath 2012;Humez et al 2015;Smith et al 2016) documented that different wells do not exhibit the same degree of variability in methane concentrations in a study area and that short-term variations may even be very significant for a given well. Dusseault and Jackson (2014) stated that hydrogeologists must consider the fact that concentrations may considerably vary over time when designing the monitoring plan for sampling groundwater in observation wells.…”

Section: Introductionmentioning

confidence: 99%

Temporal variations of methane concentration and isotopic composition in groundwater of the St. Lawrence Lowlands, eastern Canada

et al. 2017

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Dissolved methane concentrations in shallow groundwater are known to vary both spatially and temporally. However, the extent of these variations is poorly documented and this knowledge is critical for distinguishing natural fluctuations from anthropogenic impacts stemming from oil and gas activities. This issue was addressed as part of a groundwater research project aiming to assess the risk of shale gas development for groundwater quality over a 500 km 2 area in the St. Lawrence Lowlands (Quebec, Canada). A specific study was carried out to define the natural variability of methane concentrations and carbon and hydrogen isotope ratios in groundwater, as dissolved methane is naturally ubiquitous in 2 aquifers of this area. Monitoring was carried out over a period of up to 2.5 years in seven monitoring wells. Results showed that for a given well, using the same sampling depth and technique, methane concentrations can vary over time from 2.5 to 6 times relative to the lowest recorded value. Methane isotopic composition, which is a useful tool to distinguish gas origin, was found to be stable for most wells, but varied significantly over time in the two wells where methane concentrations are the lowest. The use of concentration ratios, as well as isotopic composition of methane and dissolved inorganic carbon (DIC) helped unravel the processes responsible for these variations. This study indicates that both methane concentrations and isotopic composition, as well as DIC isotopes, should be regularly monitored over at least one year to establish their potential natural variations prior to hydrocarbon development.

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Temporal variability of methane in domestic groundwater wells, northeastern Pennsylvania

Cited by 17 publications

References 24 publications

Methane in groundwater before, during, and after hydraulic fracturing of the Marcellus Shale

Methane in groundwater before, during, and after hydraulic fracturing of the Marcellus Shale

Controls on Methane Occurrences in Shallow Aquifers Overlying the Haynesville Shale Gas Field, East Texas

Temporal variations of methane concentration and isotopic composition in groundwater of the St. Lawrence Lowlands, eastern Canada

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