Methane Baseline Concentrations and Sources in Shallow Aquifers from the Shale Gas-Prone Region of the St. Lawrence Lowlands (Quebec, Canada)

Moritz, Anja; Hélie, Jean‐François; Pinti, Daniele L.; Larocque, Marie; Barnetche, Diogo; Retailleau, Sophie; Lefebvre, René; Gélinas, Yves

doi:10.1021/acs.est.5b00443

Cited by 84 publications

(82 citation statements)

References 34 publications

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“…Li and Carlson () in Colorado found that most of the methane in shallow groundwater above the Wattenberg Field is of microbial origin. On the other hand, thermogenic methane was observed in a Canadian study in areas with no hydraulic fracturing whereas data in Alberta strongly suggest a coalorigin for the shallow dissolved methane (Cheung et al ; Pinti et al ; Moritz et al ). No recent systematic peer‐reviewed research has been performed in the Texas counties of interest to this study.…”

Section: Introductionmentioning

confidence: 98%

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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Section: Introductionmentioning

confidence: 98%

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

et al. 2017

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“…Significant progress has been made in collecting data in advance of drilling for shale gas and in developing more robust geochemical and hydrogeological approaches to evaluating the source and the occurrences of methane in shallow aquifers (Darrah et al 2015a(Darrah et al , 2015bHarkness et al 2017;Heilweil et al 2015Heilweil et al , 2016Humez et al 2016;Jackson et al 2013a;Moritz et al, 2015;Nicot et al, 2017aNicot et al, , 2017bSiegel et al 2015;Vengosh et al 2014;Warner et al 2012aWarner et al , 2012bWarner et al , 2014). Yet, there is a need for modeling approaches to constrain the pathways, timing, and mechanisms of hydrocarbon migration to and within shallow aquifers (Schwartz 2013).…”

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Methane Leakage from a Faulty Natural Gas Well into Fractured Tight Formations

Moortgat¹,

Schwartz

Darrah

2018

Groundwater

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Horizontal drilling and hydraulic fracturing have enabled hydrocarbon recovery from unconventional reservoirs, but led to natural gas contamination of shallow groundwaters. We describe and apply numerical models of gas-phase migration associated with leaking natural gas wells. Three leakage scenarios are simulated: (1) high-pressure natural gas pulse released into a fractured aquifer; (2) continuous slow leakage into a tilted fractured formation; and (3) continuous slow leakage into an unfractured aquifer with fluvial channels, to facilitate a generalized evaluation of natural gas transport from faulty natural gas wells. High-pressure pulses of gas leakage into sparsely fractured media are needed to produce the extensive and rapid lateral spreading of free gas previously observed in field studies. Transport in fractures explains how methane can travel vastly different distances and directions laterally away from a leaking well, which leads to variable levels of methane contamination in nearby groundwater wells. Lower rates of methane leakage (≤1 Mcf/day) produce shorter length scales of gas transport than determined by the high-pressure scenario or field studies, unless aquifers have low vertical permeabilities (≤1 millidarcy) and fractures and bedding planes have sufficient tilt (∼10°) to allow a lateral buoyancy component. Similarly, in fractured rock aquifers or where permeability is controlled by channelized fluvial deposits, lateral flow is not sufficiently developed to explain fast-developing gas contamination (0-3 months) or large length scales (∼1 km) documented in field studies. Thus, current efforts to evaluate the frequency, mechanism, and impacts of natural gas leakage from faulty natural gas wells likely underestimate contributions from small-volume, low-pressure leakage events.

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“…There is concern regarding the potential impacts of gas and fluid movement, as well as depressurisation, on groundwater quality and quantity in adjacent aquifers used to support other industries (Atkins et al, 2015;Heilweil et al, 2015;Iverach et al, 2015;Moritz et al, 2015;Owen et al, 2016;Zhang and Soeder, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Throughout the world the occurrence of freshwater aquifers adjacent to unconventional-gas production is common (Osborn et al, 2011;Moore, 2012;Roy and Ryan, 2013;Vidic et al, 2013;Vengosh et al, 2014;Moritz et al, 2015). We have previously shown that there may be local natural connectivity between the WCM and the CRAA (Iverach et al, 2015 ], δ 13 C-CH 4 , δ 13 C-DIC, δ 13 C-DOC and δ 2 H-H 2 O), as well as characterisation of microbiological communities present, can inform the discussion surrounding the occurrence of CH 4 and its potential for upward migration in the groundwater of the CRAA.…”

Section: Introductionmentioning

confidence: 99%

Biogeochemical constraints on the origin of methane in an alluvial aquifer: evidence for the upward migration of methane from underlying coal measures

et al. 2017

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Abstract. Geochemical and microbiological indicators of methane (CH 4 ) production, oxidation and migration processes in groundwater are important to understand when attributing sources of gas. The processes controlling the natural occurrence of CH 4 in groundwater must be understood, especially when considering the potential impacts of the global expansion of coal seam gas (CSG) production on groundwater quality and quantity. We use geochemical and microbiological data, along with measurements of CH 4 isotopic composition (δ 13 C-CH 4 ), to determine the processes acting upon CH 4 in a freshwater alluvial aquifer that directly overlies coal measures targeted for CSG production in Australia. Measurements of CH 4 indicate that there is biogenic CH 4 in the aquifer; however, microbial data indicate that there are no methanogenic archaea in the groundwater. In addition, geochemical data, particularly the isotopes of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC), as well as the concentration of SO 2− 4 , indicate limited potential for methanogenesis in situ. Microbial community analysis also shows that aerobic oxidation of CH 4 occurs in the alluvial aquifer. The combination of microbiological and geochemical indicators suggests that the most likely source of CH 4 , where it was present in the freshwater aquifer, is the upward migration of CH 4 from the underlying coal measures.

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Methane Baseline Concentrations and Sources in Shallow Aquifers from the Shale Gas-Prone Region of the St. Lawrence Lowlands (Quebec, Canada)

Cited by 84 publications

References 34 publications

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

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

Numerical Modeling of Methane Leakage from a Faulty Natural Gas Well into Fractured Tight Formations

Biogeochemical constraints on the origin of methane in an alluvial aquifer: evidence for the upward migration of methane from underlying coal measures

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