Characterization of geothermal reservoirs with electrical surveys: Beowawe geothermal field

Garg, S.K.; Pritchett, J.W.; Wannamaker, Philip E.; Combs, James G.

doi:10.1016/j.geothermics.2007.07.005

Cited by 33 publications

(22 citation statements)

References 9 publications

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“…In particular, from the definition of these parameters in (1), small values of m and τ are associated with small values of F and φ, which correspond to highly conductive domains characterized by a small porosity. This implies that the minimum values of m and τ are related to fracture-matrix systems that optimize the ratio of conductivity to porosity, which is observed here for relatively long fractures that are spatially distributed throughout the systems (Figures 4b,c and 5b).…”

Section: Results At the Fracture Percolation Thresholdmentioning

confidence: 99%

“…Evaluating subsurface rock properties is a critical challenge in a wide variety of research fields and applications including hydrogeology, geothermal energy, natural resource prospecting and the long-term storage of toxic waste (e.g., [1][2][3]). In the case of fractured rocks, the main challenge is to identify the presence of fractures and estimate their properties, as these highly permeable structures play a key role in the natural environment (e.g., [4][5][6]).…”

Section: Introductionmentioning

confidence: 99%

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Relating Topological and Electrical Properties of Fractured Porous Media: Insights into the Characterization of Rock Fracturing

2018

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Numerous laboratory and field experiments suggest that electrical properties of fractured rocks may provide critical information regarding the topological properties of the underlying fracture networks. However, a lack of numerical studies dedicated to realistic fractured media prevents us from assessing, in a systematic manner, the relationships between electrical and topological properties in complex domains for which a representative elementary volume may not exist. To address this issue, we conduct an extended numerical analysis over a large range of realistic fractured porous media with an explicit description of the fractures that takes into account the fracture-matrix interactions. Our work shows that the fracture density determines the suitability of Archie's law for describing effective electrical properties with complex behavior associated with small fracture densities. In particular, for fracture networks at the percolation threshold surrounded by a low-porosity matrix, the effective petrophysical relationships are impacted by the assumed fracture-length distribution and the exchange of electric current between the fractures and surrounding matrix. These results help in understanding experimental observations that were difficult to explain so far, suggesting that the effective electrical properties of fractured rock may be used to obtain insights into the properties of their geological structures.

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Section: Results At the Fracture Percolation Thresholdmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Relating Topological and Electrical Properties of Fractured Porous Media: Insights into the Characterization of Rock Fracturing

2018

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“…In those situations, ERT can detect the reservoir itself, map preferential flow paths, and be useful to characterize rock properties [97][98][99][100]. Recently, several studies were carried out to image volcano hydrothermal systems with very long resistivity cables, showing that ERT is a reliable tool to detect hydrothermal features [101,102].…”

Section: Using Ert To Monitor Temperature Changesmentioning

confidence: 99%

Geophysical Methods for Monitoring Temperature Changes in Shallow Low Enthalpy Geothermal Systems

Hermans

Nguyen

Robert³

et al. 2014

Energies

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Low enthalpy geothermal systems exploited with ground source heat pumps or groundwater heat pumps present many advantages within the context of sustainable energy use. Designing, monitoring and controlling such systems requires the measurement of spatially distributed temperature fields and the knowledge of the parameters governing groundwater flow (permeability and specific storage) and heat transport (thermal conductivity and volumetric thermal capacity). Such data are often scarce or not available. In recent years, the ability of electrical resistivity tomography (ERT), self-potential method (SP) and distributed temperature sensing (DTS) to monitor spatially and temporally temperature changes in the subsurface has been investigated. We review the recent advances in using these three methods for this type of shallow applications. A special focus is made regarding the petrophysical relationships and on underlying assumptions generally needed for a quantitative interpretation of these geophysical data. We show that those geophysical methods are mature to be used within the context of temperature monitoring and that a combination of them may be the best choice regarding control and validation issues. OPEN ACCESSEnergies 2014, 7 5084

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“…In those situations, ERT can detect the reservoir itself, map preferential flow paths, and is useful to characterize rock properties (e.g., Pérez-Flores and Gomez Trevino, 1997;Bruno et al, 2000;Garg et al, 2007;Arango-Galván et al, 2011). Recently, several studies were carried out to image volcano hydrothermal systems with very long resistivity cables, showing that ERT is a reliable tool to detect hydrothermal features (e.g., Revil et al, 2010Revil et al, , 2011.…”

Section: Introductionmentioning

confidence: 99%

A shallow geothermal experiment in a sandy aquifer monitored using electric resistivity tomography

et al. 2012

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Groundwater resources are increasingly used around the world for geothermal exploitation systems. To monitor such systems and to estimate their governing parameters, we rely mainly on borehole observations of the temperature field at a few locations. Bulk electric resistivity variations can bring important information on temperature changes in aquifers. We have used surface electric resistivity tomography to monitor spatially temperature variations in a sandy aquifer during a thermal injection test. Heated water (48°C) was injected for 70 hours at the rate of 87 l∕h in a 10.5°C aquifer. Temperature changes derived from time-lapse electric images were in agreement with laboratory water electric conductivity-temperature measurements. In parallel, a coupled hydrogeologic saturated flow and heat transport model was calibrated on geophysical data for the conceptual model, and on hydrogeologic and temperature data for the parameters. The resistivity images showed an upper flow of heated water along the well above the injection screens and led to a new conceptualization of the hydrogeologic source term. The comparison between the temperature models derived from resistivity images and from the simulations was satisfactory. Quantitatively, resistivity changes allowed estimating temperature changes within the aquifer, and qualitatively, the heated plume evolution was successfully monitored. This work demonstrates the ability of electric resistivity tomography to study heat and storage experiments in shallow aquifers. These results could potentially lead to a number of practical applications, such as the monitoring or the design of shallow geothermal systems.

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Characterization of geothermal reservoirs with electrical surveys: Beowawe geothermal field

Cited by 33 publications

References 9 publications

Relating Topological and Electrical Properties of Fractured Porous Media: Insights into the Characterization of Rock Fracturing

Relating Topological and Electrical Properties of Fractured Porous Media: Insights into the Characterization of Rock Fracturing

Geophysical Methods for Monitoring Temperature Changes in Shallow Low Enthalpy Geothermal Systems

A shallow geothermal experiment in a sandy aquifer monitored using electric resistivity tomography

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