Cross-hole fracture connectivity assessed using hydraulic responses during liner installations in crystalline bedrock boreholes

Persaud, Elisha; Levison, Jana; Pehme, Peeter; Novakowski, Kent; Parker, Beth L.

doi:10.1016/j.jhydrol.2017.11.008

Cited by 9 publications

(3 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Within the 55 ha field site there is a 65 m by 30 m well field consisting of nine monitoring wells, including one inclined borehole and one multi-level well. For a detailed description and characterization of the well network refer to (Persaud et al, 2018). Beyond the well field there are two additional multi-level wells each with three monitoring intervals.…”

Section: Kennedy Field Stationmentioning

confidence: 99%

“…The well field is predominantly mafic gneiss, however, the remainder of the site contacts the Gull River (limestone) and Shadow Lake Formations (argillaceous sandstone and shale) of the Simcoe Group and carbonate metasedimentary rocks of the Grenville Supergroup (Ontario Geological Survey, 2011, 2001. Testing of the well field by Persaud et al (2018) identified significant sub-horizontal fracture sets trending northeast-southwest, which is anticipated to influence the direction of horizontal flow in the area, particularly in the metasedimentary, gneissic units. Transmissivity for the Simcoe Group has a geometric mean of 6.6×10 -5 m 2 /s (Singer et al, 2003) and transmissivity for the Precambrian rocks are similar to that of the Tay site.…”

Section: Kennedy Field Stationmentioning

confidence: 99%

See 1 more Smart Citation

Groundwater recharge, flow and stable isotope attenuation in sedimentary and crystalline fractured rocks: Spatiotemporal monitoring from multi-level wells

Wright

Novakowski

2019

Journal of Hydrology

View full text Add to dashboard Cite

The complexities of fractured rock systems necessitate the use of multi-level monitoring wells for the measurement of isotopic tracers with depth. These methods, however, are rarely employed in groundwater flow studies, particularly involving temporal isotope measurements in multiple rock types. To understand the use of isotopic snowmelt tracers for exploring surface connections and recharge, an investigation was undertaken at three geologically-distinct field sites in south-eastern Ontario, Canada. Results of constant head injection tests at 2-m intervals were used to identify and isolate high transmissivity zones (2-3 in each well) for the construction of eight multi-level wells (22 intervals) for groundwater sampling. Deuterium and oxygen-18 were measured in rain (n=64), snow (n=67), soil water (n=118) and groundwater (n=594) on a bi-weekly to monthly basis over two seasonal snowmelt cycles (> 1.5 years). In combination with stable isotopes, measurements of hydraulic head, groundwater temperature, specific conductance and two rounds of tritium sampling contributed to the development of a conceptual model for snowmelt recharge and flow in sandstone, limestone and crystalline rock. Seasonal variation of ẟ 2 H and ẟ 18 O was observed in all rock types indicating recent recharge and strong surface connections. The dampening and residence time of the snowmelt tracer increased with depth in crystalline rock. Attenuation was highest in higherporosity sedimentary rock and strong confining conditions were observed to inhibit recent recharge.Substantial isotopic attenuation measured in the overburden indicated that the strong snowmelt signal measured in groundwater stems from water infiltrating through areas with thin or no overburden.Identification of the periodic trends and distinct isotopic horizons in this study would not have been possible without the use of multi-level wells.

show abstract

Section: Kennedy Field Stationmentioning

confidence: 99%

Section: Kennedy Field Stationmentioning

confidence: 99%

Groundwater recharge, flow and stable isotope attenuation in sedimentary and crystalline fractured rocks: Spatiotemporal monitoring from multi-level wells

Wright

Novakowski

2019

Journal of Hydrology

View full text Add to dashboard Cite

show abstract

“…Numerous field methods, such as flow metering, constant head tests, and FLUTe liner profiling can be used for the determination of fracture properties (Price et al 1980;Frampton and Cvetkovic, 2010;Nastev et al 2004;Parker et al 2012;Persaud et al 2018;Quinn et al 2011;Quinn et al 2012). One of the most widely-utilized methods is constant head testing using straddle-packer systems (NASEM, 2015;Novakowski et al 2007;Quinn et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Allocating transmissivities from constant head tests for the development of DFN models

Howroyd

Novakowski

2022

Can. Geotech. J.

View full text Add to dashboard Cite

Constant head tests are commonly used for field measurements of fracture transmissivity. As a bulk transmissivity is measured for each test section, it is frequently unclear how this transmissivity relates to the hydraulic properties of individual fractures. The goal of this study is to determine if constant head tests conducted at scales larger than the average fracture spacing can be used to generate discrete fracture network (DFN) models that describe transport. The methodology involved generating DFNs using measurements from constant head tests conducted at lengths both above and below the average fracture spacing at a site in Ontario, Canada. Transport predictions from DFNs produced from different scales of hydraulic tests were compared to determine if a method for proportioning larger-scale test results to obtain a DFN representative of the smaller-scale tests could be established. The results of this study indicate that the choice of method used to apportion bulk transmissivities has a significant impact on transport simulations, with a difference in mass arrival of over a factor of two at travel distances less than 50 m. While the most appropriate method is case specific, the error resulting from the choice needs to be considered when using DFN models.

show abstract

Effect of liquid CO₂ phase change on pores and fractures in coal: An experimental study

Jiang,

Gao,

Liu

et al. 2024

Energy Science & Engineering

View full text Add to dashboard Cite

The evolution characteristics of pores and fractures in coal after liquid carbon dioxide (CO2) phase change are important factors that determine the permeability increase effect. Therefore, it is critical to correctly understand the influences of liquid CO2 phase change on pores and fractures in coal. The changes of adsorption and desorption isotherm, pore size, pore volume, and specific surface area of fractured coal and fractured coal were compared by low temperature liquid nitrogen adsorption experiment. In addition, a scanning electron microscope was adopted to observe fracture characteristics of fractured and unfractured coal samples and analyze changes in the connectivity and fracture development. Experimental results show that the fractured coal samples exhibit better hysteresis loops and a larger proportion of gas desorption than the unfractured ones. Fractured coal samples contain more developed pores and fractures compared with unfractured ones, and their fragmentation degree, pore diameter, fracture width, and connectivity of pores and fractures are also better. Besides, the closer the samples from the fracturing boreholes are, the better the fracturing effect. This indicates that liquid CO2 phase change can effectively enhance the gas transport capacity in pores and fractures in coal. The research results provide a solid basis for the better application of liquid CO2 phase‐change fracturing to the prevention of coal and gas outburst disasters and the realization of efficient gas extraction in deep coal seams.

show abstract

Cross-hole fracture connectivity assessed using hydraulic responses during liner installations in crystalline bedrock boreholes

Cited by 9 publications

References 64 publications

Groundwater recharge, flow and stable isotope attenuation in sedimentary and crystalline fractured rocks: Spatiotemporal monitoring from multi-level wells

Groundwater recharge, flow and stable isotope attenuation in sedimentary and crystalline fractured rocks: Spatiotemporal monitoring from multi-level wells

Allocating transmissivities from constant head tests for the development of DFN models

Effect of liquid CO₂ phase change on pores and fractures in coal: An experimental study

Contact Info

Product

Resources

About

Cross-hole fracture connectivity assessed using hydraulic responses during liner installations in crystalline bedrock boreholes

Cited by 9 publications

References 64 publications

Groundwater recharge, flow and stable isotope attenuation in sedimentary and crystalline fractured rocks: Spatiotemporal monitoring from multi-level wells

Groundwater recharge, flow and stable isotope attenuation in sedimentary and crystalline fractured rocks: Spatiotemporal monitoring from multi-level wells

Allocating transmissivities from constant head tests for the development of DFN models

Effect of liquid CO2 phase change on pores and fractures in coal: An experimental study

Contact Info

Product

Resources

About

Effect of liquid CO₂ phase change on pores and fractures in coal: An experimental study