Measurements of groundwater velocity in discrete rock fractures

Novakowski, Kent; Bickerton, Greg; Lapcevic, P. A.; Voralek, J.; Ross, Nathalie

doi:10.1016/j.jconhyd.2005.09.001

Cited by 72 publications

(40 citation statements)

References 11 publications

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“…The flow of gas and its transport processes in porous formations can be described mathematically from the principle of mass conservation of fluid/solute and Newton's 2nd law of motion [6]. The general equation for conservation of mass or volume in porous media is as follows:(rate of mass inflow)-(rate of mass out flow)+(rate of mass production/ production)=(rate of mass accumulation) ( Table 5).…”

Section: Darcy Law With Adsorptionmentioning

confidence: 99%

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Effect of Initial Pressure, Surface, and Outlet Velocity, and Density of Adsorbed Gas on Transport and Production in Shale Gas Reservoirs

Wb¹,

Aminu²

2017

Oil Gas Res

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The recent technological advancements in horizontal drilling and hydraulic fracturing have led to a boom in gas production from unconventional shale gas reservoirs. However, knowledge and technologies required to successfully develop unconventional reservoirs are far beyond what is available in the industry at present. Shale gas reservoirs are extremely heterogeneous with ultra-low permeability and nano-pores. The flow of gas in this reservoir is non-linear, multi-faceted including adsorption/desorption, flow at high and low rates, solid-fluid interactions, etc., which makes it a significant challenge to quantify such flow. A pore-scale flow model was developed using a combination of CFD and COMSOL multi-physics 4.2 based on Darcy and Navier-Stokes equations to describe transport of adsorbed gas and free gas in pore spaces respectively. Parameters such as surface pressure, adsorbed gas density and initial reservoir pressure were used to study shale gas transport. The presence of adsorbed gas within the shale gas reservoir will decrease porosity while increasing total production and gas storage capacity due to the high affinity of surfaces of organic matter to methane found within the shale gas reservoirs and hence high gas-in-place estimates. Moreover, because production from the adsorbed gas phase is dependent on pressure, four different values of initial reservoir pressures were used to analyze the effect of reservoir pressure on flow velocity. It was observed that the higher the initial reservoir pressure, the greater the velocity of the flow and consequently higher production rates.

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Section: Darcy Law With Adsorptionmentioning

confidence: 99%

“…The Langmuir isotherm describes the effect of pressure on adsorption in shale gas reservoirs based on a Langmuir volume and Langmuir pressure of 9.8000e-4 m³/kg and 3.0500e 6 Pa respectively. Fluid viscosity at initial reservoir condition is 0.01804 cp.…”

Section: Single Phase Flow With Adsorbed Gasmentioning

confidence: 99%

Effect of Initial Pressure, Surface, and Outlet Velocity, and Density of Adsorbed Gas on Transport and Production in Shale Gas Reservoirs

Wb¹,

Aminu²

2017

Oil Gas Res

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“…Local characterization of the Eramosa Member, including description of fracture frequency, size, and orientation, hydraulic head, and numerous packer tests, indicates a very heterogeneous aquifer with high fracture frequency. The Eramosa Member is quite conductive, and with numerous domestic wells screened in the unit, it is an important regional aquifer (Golder Associates Ltd ; Lapcevik et al ; Novakowski et al ; Zanini et al ). The estimated hydraulic conductivity values are orders of magnitude larger in the Eramosa Member than for the underlying layer (the Upper Vinemount Member), thus it is considered to be isolated from deeper layers by this local aquitard unit (Golder Associates Ltd ).…”

Section: Site Hydrogeologymentioning

confidence: 99%

Compound‐Specific Isotope Analyses to Assess TCE Biodegradation in a Fractured Dolomitic Aquifer

et al. 2016

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The potential for trichloroethene (TCE) biodegradation in a fractured dolomite aquifer at a former chemical disposal site in Smithville, Ontario, Canada, is assessed using chemical analysis and TCE and cis-DCE compound-specific isotope analysis of carbon and chlorine collected over a 16-month period. Groundwater redox conditions change from suboxic to much more reducing environments within and around the plume, indicating that oxidation of organic contaminants and degradation products is occurring at the study site. TCE and cis-DCE were observed in 13 of 14 wells sampled. VC, ethene, and/or ethane were also observed in ten wells, indicating that partial/full dechlorination has occurred. Chlorine isotopic values (δ Cl) range between 1.39 to 4.69‰ SMOC for TCE, and 3.57 to 13.86‰ SMOC for cis-DCE. Carbon isotopic values range between -28.9 and -20.7‰ VPDB for TCE, and -26.5 and -11.8‰ VPDB for cis-DCE. In most wells, isotopic values remained steady over the 15-month study. Isotopic enrichment from TCE to cis-DCE varied between 0 and 13‰ for carbon and 1 and 4‰ for chlorine. Calculated chlorine-carbon isotopic enrichment ratios (ϵ /ϵ ) were 0.18 for TCE and 0.69 for cis-DCE. Combined, isotopic and chemical data indicate very little dechlorination is occurring near the source zone, but suggest bacterially mediated degradation is occurring closer to the edges of the plume.

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“…The large distance between gas vents is another problem to assume uniform flow in the landfill. Another method to determine groundwater velocity is a borehole tracer method (Novakowski et al, 2006;Williams et al, 2006). This method involves monitoring the change in tracer concentration after tracer is injected into isolated area in a borehole spaced by inflated packers.…”

Section: Tracer Test For Leachate Velocitymentioning

confidence: 99%

Estimation of water movement in a closed landfill based on tracer tests in gas vents and changes in leachate quality

et al. 2009

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Leachate accumulation was found in Nakazono landfill, in Asahikawa, Japan because of an insufficient leachate collection and drainage system. In order to lower leachate level in the landfill and to promote stabilization of waste, many passive gas vents were installed as well as leachate collection vaults. This study aimed to evaluate the distribution and movement of leachate in the landfill by determining leachate level and tracer test in the gas vents.The water level varied widely among the gas vents and depended mainly on the original ground level and the depth of the vent. Leachate velocity also showed a wide variation. The leachate velocity was high in the upper layers of the saturated zone in a gas vent. However, this is only the superficial velocity caused by an inflow from unsaturated layers. A sharp decrease in TOC, which was observed in most of the gas vents by installation of vents, were likely due to the effect of aerobic biodegradation in the unsaturated layer of waste. This effect is limited to the small aerobic zone around the gas vent.

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Measurements of groundwater velocity in discrete rock fractures

Cited by 72 publications

References 11 publications

Effect of Initial Pressure, Surface, and Outlet Velocity, and Density of Adsorbed Gas on Transport and Production in Shale Gas Reservoirs

Effect of Initial Pressure, Surface, and Outlet Velocity, and Density of Adsorbed Gas on Transport and Production in Shale Gas Reservoirs

Compound‐Specific Isotope Analyses to Assess TCE Biodegradation in a Fractured Dolomitic Aquifer

Estimation of water movement in a closed landfill based on tracer tests in gas vents and changes in leachate quality

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