Understanding shallow and deep flow for assessing the risk of hydrocarbon development to groundwater quality

Raynauld, Mélanie; Peel, Morgan; Lefebvre, René; Molson, John; Crow, Heather; Ahad, Jason M. E.; Ouellet, Michel; Aquilina, Luc

doi:10.1016/j.marpetgeo.2016.09.026

Cited by 9 publications

(8 citation statements)

References 28 publications

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“…Unfortunately, few mandatory predevelopment groundwater characterization programs are conducted in regions of intense energy resource development prior to drilling. A key exception to this is the work performed in Quebec, Canada where a moratorium on development is currently in place . Nonetheless, natural subsurface and groundwater methane conditions in regions of historic, ongoing or planned development remain poorly understood.…”

Section: Key Knowledge Gaps Relating To Gas Migration and Fugitive Gasmentioning

confidence: 99%

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Advancing knowledge of gas migration and fugitive gas from energy wells in northeast British Columbia, Canada

et al. 2019

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Petroleum resource development is creating a global legacy of active and inactive onshore energy wells. Unfortunately, a portion of these wells will exhibit gas migration (GM), releasing fugitive gas (FG) into adjacent geologic formations and overlying soils. Once mobilized, FG may traverse the critical zone, impact groundwater, and emit to the atmosphere, contributing to greenhouse‐gas emissions. Understanding of GM and FG has increased in recent years but significant gaps persist in knowledge of (1) the incidence and causes of GM, (2) subsurface baseline conditions in regions of development required to delineate GM and FG, and (3) the migration, impacts, and fate of FG. Here we provide an overview of these knowledge gaps as well as the occurrence of GM and FG as currently understood in British Columbia (BC), Canada, a petroleum‐producing region hosting significant reserves. To address the identified knowledge gaps within BC, the Energy and Environment Research Initiative (EERI) at the University of British Columbia is implementing several field‐focused research projects including: (1) statistical analyses of regulatory data to elucidate the incidence and causes of GM, (2) characterization of regional hydrogeology and shallow subsurface conditions in the Peace Region of the Montney resource play, and (3) investigation of the migration, impacts, and fate of FG in the shallow subsurface through controlled natural‐gas release. Together, the EERI investigations will advance understanding of GM and FG, provide scientific data that can inform regulations, and aid development of effective monitoring and detection methodologies for BC and beyond. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

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Section: Key Knowledge Gaps Relating To Gas Migration and Fugitive Gasmentioning

confidence: 99%

“…A key exception to this is the work performed in Quebec, Canada where a moratorium on development is currently in place. [49][50][51] Nonetheless, natural subsurface and groundwater methane conditions in regions of historic, ongoing or planned development remain poorly understood.…”

Section: Understanding Of Baseline Groundwater Conditions In Regions mentioning

confidence: 99%

Advancing knowledge of gas migration and fugitive gas from energy wells in northeast British Columbia, Canada

et al. 2019

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“…So far, shallow aquifer vulnerability related to activities carried out at great depths (including hydraulic fracturing) has been the object of a limited number of studies, mainly because 1) the possibility of upward fluid migration through natural preferential pathways is perceived by some as being highly improbable and is still the object of an ongoing scientific debate (Vengosh et al, 2014;Birdsell et al, 2015;Lefebvre, 2017) and 2) very little information is available on the intermediate zone, located below shallow aquifers and above the zone targeted by the hydrocarbon industry (see Figure 1). It is, however, generally accepted that a natural connection between shallow and deep formations may be possible if large-scale permeable discontinuities (such as fault zones) are present across this intermediate zone, constituting preferential migration pathways (Gassiat et al, 2013;Kissinger et al, 2013;Vengosh et al, 2014;Raynauld et al, 2016;Lefebvre, 2017). The expression of vertical fluid migration is difficult to directly visualize in continental settings.…”

Section: Contextmentioning

confidence: 99%

“…This concern is even stronger in regions where aquifers represent the main water supply and where hydrocarbon development has not yet taken place (Raynauld et al, 2016). As a result, these perceived environmental issues have sometimes led to moratoria on hydraulic fracturing, such as in eastern Canada and northeastern USA, while in other areas (mostly where oil and gas production has been on-going for decades), concerns and regulatory efforts focussed on how to minimize or mitigate impacts (Esterhuyse, 2017).…”

Section: Contextmentioning

confidence: 99%

Assessing potential impacts of shale gas development on shallow aquifers through upward fluid migration: A multi-disciplinary approach applied to the Utica Shale in eastern Canada

Rivard

Bordeleau

Lavoie

et al. 2019

Marine and Petroleum Geology

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Potential impacts of shale gas development on shallow aquifers has raised concerns, especially regarding groundwater contamination. The intermediate zone separating shallow aquifers from shale gas reservoirs plays a critical role in aquifer vulnerability to fluid upflow, but the assessment of such vulnerability is challenging due to the general paucity of data in this intermediate zone. The ultimate goal of the project reported here was to develop a holistic multi-geoscience methodology to assess potential impacts of unconventional hydrocarbon development on freshwater aquifers related to upward migration through natural pathways. The study area is located in the St. Lawrence Lowlands (southern Quebec, Canada), where limited oil and gas exploration and no shale gas production have taken place. A large set of data was collected over a ~500 km 2 area near a horizontal shale gas exploration well completed and fracked into the Utica Shale at a depth of 2 km. To investigate the intermediate zone integrity, this project integrated research results from multiple sources in order to obtain a better understanding of the system hydrodynamics, including geology, hydrogeology, deep and shallow geophysics, soil, rock and groundwater geochemistry, and geomechanics. The combined interpretation of the multidisciplinary dataset demonstrates that there is no evidence of, and a very limited potential for, upward fluid migration from the Utica Shale reservoir to the shallow aquifer. Microbial and thermogenic methane in groundwater of this region appear to come from the shallow, organic-rich, fractured sedimentary rocks making up the regional aquifer. Nonetheless, diluted brines present in a few shallow wells close to and downstream of a normal fault revealed that some upward groundwater migration occurs, but only over a few hundred meters from the surface based on the isotopic signature of methane. The 3 methodology developed should help support regulations related to shale gas development aiming to protect groundwater.

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“…The Haldimand sector, Gaspé, Québec, Canada (Figure 1 shallow fractured rock aquifer system (Raynauld et al, 2014;Raynauld et al, 2016). The drilling of a horizontal exploration well was halted in December by a municipal regulation aimed at protecting the local groundwater, although several vertical exploration wells had been previously drilled in the region.…”

Section: Study Sites and Samplesmentioning

confidence: 99%

Naphthenic acids in groundwater overlying undeveloped shale gas and tight oil reservoirs

et al. 2018

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The acid extractable organics (AEOs) containing naphthenic acids (NAs) in groundwater overlying undeveloped shale gas (Saint-Édouard region) and tight oil (Haldimand sector, Gaspé) reservoirs in Québec, Canada, were analysed using high resolution Orbitrap mass spectrometry and thermal conversion/elemental analysis - isotope ratio mass spectrometry. As classically defined by CHO, the most abundant NAs detected in the majority of groundwater samples were straight-chain (Z = 0) or monounsaturated (Z = -2) C and C fatty acids. Several groundwater samples from both study areas, however, contained significant proportions of presumably alicyclic bicyclic NAs (i.e., Z = -4) in the C-C range. These compounds may have originated from migrated waters containing a different distribution of NAs, or are the product of in situ microbial alteration of shale organic matter and petroleum. In most groundwater samples, intramolecular carbon isotope values generated by pyrolysis (δC) of AEOs were on average around 2-3‰ heavier than those generated by bulk combustion (δC) of AEOs, providing further support for microbial reworking of subsurface organic carbon. Although concentrations of AEOs were very low (<2.0 mg/L), the detection of potentially toxic bicyclic acids in groundwater overlying unconventional hydrocarbon reservoirs points to a natural background source of organic contaminants prior to any large-scale commercial hydrocarbon development.

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Understanding shallow and deep flow for assessing the risk of hydrocarbon development to groundwater quality

Cited by 9 publications

References 28 publications

Advancing knowledge of gas migration and fugitive gas from energy wells in northeast British Columbia, Canada

Advancing knowledge of gas migration and fugitive gas from energy wells in northeast British Columbia, Canada

Assessing potential impacts of shale gas development on shallow aquifers through upward fluid migration: A multi-disciplinary approach applied to the Utica Shale in eastern Canada

Naphthenic acids in groundwater overlying undeveloped shale gas and tight oil reservoirs

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