Reply [to “Comment on ‘Flow and tracer transport in a single fracture: A stochastic model and its relation to some field observations’ by L. Moreno et al.”]

1991 ◽  
Vol 27 (1) ◽  
pp. 133-134 ◽  
Author(s):  
L. Moreno ◽  
Y. W. Tsang ◽  
C. F. Tsang
Keyword(s):  
Stochastic Model ◽  
Single Fracture ◽  
Field Observations ◽  
Tracer Transport

Flow and tracer transport in a single fracture: A stochastic model and its relation to some field observations

1988 ◽  
Vol 24 (12) ◽  
pp. 2033-2048 ◽  
Author(s):  
L. Moreno ◽  
Y. W. Tsang ◽  
C. F. Tsang ◽  
F. V. Hale ◽  
I. Neretnieks
Keyword(s):  
Stochastic Model ◽  
Single Fracture ◽  
Field Observations ◽  
Tracer Transport

scholarly journals Laboratory experimental investigation of heat transport in fractured media

2016 ◽  
Author(s):  
Claudia Cherubini ◽  
Nicola Pastore ◽  
Concetta I. Giasi ◽  
Nicoletta Maria Allegretti
Keyword(s):  
Heat Transport ◽  
Power Plants ◽  
Time Moment ◽  
Experimental Studies ◽  
Renewable Resource ◽  
Fractured Media ◽  
Single Fracture ◽  
Tracer Transport ◽  
Transport Dynamics ◽  
Experimental Apparatus

Abstract. Low enthalpy geothermal energy is a renewable resource that is still underexploited nowadays, in relation to its potential for development in the society worldwide. Most of its applicabilities have already been investigated, such as: heating and cooling of private and public buildings, roads defrost, cooling of industrial processes, food drying systems, desalination. One of the major limitations related to the choice of installing low enthalpy geothermal power plants regards the initial investment costs. In order to increase the optimal efficiency of installations which use groundwater as geothermal resource, flow and heat transport dynamics in aquifers need to be well characterized. Especially in fractured rock aquifers these processes represent critical elements that are not well known. Therefore there is a tendency to oversize geothermal plants. In literature there are very few studies on heat transport especially in fractured media. This study is aimed to deepen the understanding of this topic through heat transport experiments in fractured network and their interpretation. The heat transfer tests have been carried out on the experimental apparatus previously employed to perform flow and tracer transport experiments, which has been modified in order to analyze heat transport dynamics in a network of fractures. In order to model the obtained thermal breakthrough curves, the Explicit Network Model (ENM) has been used, which is based on an adaptation of a Tang's solution for the transport of the solutes in a semi-infinite single fracture embedded in a porous matrix. Parameter estimation, time moment analysis, tailing character and other dimensionless parameters have permitted to better understand the dynamics of heat transport and the efficiency of heat exchange between the fractures and matrix. The results have been compared with the previous experimental studies on solute transport.

scholarly journals Laboratory experimental investigation of heat transport in fractured media

2017 ◽  
Vol 24 (1) ◽  
pp. 23-42 ◽  
Author(s):  
Claudia Cherubini ◽  
Nicola Pastore ◽  
Concetta I. Giasi ◽  
Nicoletta Maria Allegretti
Keyword(s):  
Heat Transport ◽  
Time Moment ◽  
Fractured Media ◽  
Single Fracture ◽  
Tracer Transport ◽  
Initial Development ◽  
Capital Costs ◽  
Transport Dynamics ◽  
Experimental Apparatus ◽  
Geothermal Power

Abstract. Low enthalpy geothermal energy is a renewable resource that is still underexploited nowadays in relation to its potential for development in society worldwide. Most of its applications have already been investigated, such as heating and cooling of private and public buildings, road defrosting, cooling of industrial processes, food drying systems or desalination. Geothermal power development is a long, risky and expensive process. It basically consists of successive development stages aimed at locating the resources (exploration), confirming the power generating capacity of the reservoir (confirmation) and building the power plant and associated structures (site development). Different factors intervene in influencing the length, difficulty and materials required for these phases, thereby affecting their cost. One of the major limitations related to the installation of low enthalpy geothermal power plants regards the initial development steps that are risky and the upfront capital costs that are huge. Most of the total cost of geothermal power is related to the reimbursement of invested capital and associated returns. In order to increase the optimal efficiency of installations which use groundwater as a geothermal resource, flow and heat transport dynamics in aquifers need to be well characterized. Especially in fractured rock aquifers these processes represent critical elements that are not well known. Therefore there is a tendency to oversize geothermal plants. In the literature there are very few studies on heat transport, especially on fractured media. This study is aimed at deepening the understanding of this topic through heat transport experiments in fractured networks and their interpretation. Heat transfer tests have been carried out on the experimental apparatus previously employed to perform flow and tracer transport experiments, which has been modified in order to analyze heat transport dynamics in a network of fractures. In order to model the obtained thermal breakthrough curves, the Explicit Network Model (ENM) has been used, which is based on an adaptation of Tang's solution for the transport of the solutes in a semi-infinite single fracture embedded in a porous matrix. Parameter estimation, time moment analysis, tailing character and other dimensionless parameters have permitted a better understanding of the dynamics of heat transport and the efficiency of heat exchange between the fractures and the matrix. The results have been compared with the previous experimental studies on solute transport.

scholarly journals The Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS) – Part 2: Model sensitivity to the biomass burning inventories

2010 ◽  
Vol 10 (13) ◽  
pp. 5785-5795 ◽  
Author(s):  
K. M. Longo ◽  
S. R. Freitas ◽  
M. O. Andreae ◽  
A. Setzer ◽  
E. Prins ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Biomass Burning ◽  
Transport Model ◽  
Atmospheric Modeling ◽  
Field Observations ◽  
Tracer Transport ◽  
Regional Atmospheric Modeling System ◽  
Fire Emissions ◽  
Direct Measurements ◽  
Regional Atmospheric Modeling

Abstract. We describe an estimation technique for biomass burning emissions in South America based on a combination of remote-sensing fire products and field observations, the Brazilian Biomass Burning Emission Model (3BEM). For each fire pixel detected by remote sensing, the mass of the emitted tracer is calculated based on field observations of fire properties related to the type of vegetation burning. The burnt area is estimated from the instantaneous fire size retrieved by remote sensing, when available, or from statistical properties of the burn scars. The sources are then spatially and temporally distributed and assimilated daily by the Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS) in order to perform the prognosis of related tracer concentrations. Three other biomass burning inventories, including GFEDv2 and EDGAR, are simultaneously used to compare the emission strength in terms of the resultant tracer distribution. We also assess the effect of using the daily time resolution of fire emissions by including runs with monthly-averaged emissions. We evaluate the performance of the model using the different emission estimation techniques by comparing the model results with direct measurements of carbon monoxide both near-surface and airborne, as well as remote sensing derived products. The model results obtained using the 3BEM methodology of estimation introduced in this paper show relatively good agreement with the direct measurements and MOPITT data product, suggesting the reliability of the model at local to regional scales.

scholarly journals The Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS) – Part 2: Model sensitivity to the biomass burning inventories

2007 ◽  
Vol 7 (3) ◽  
pp. 8571-8595 ◽  
Author(s):  
K. M. Longo ◽  
S. R. Freitas ◽  
A. Setzer ◽  
E. Prins ◽  
P. Artaxo ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Biomass Burning ◽  
Transport Model ◽  
Atmospheric Modeling ◽  
Field Observations ◽  
Tracer Transport ◽  
Regional Atmospheric Modeling System ◽  
Near Surface ◽  
Direct Measurements ◽  
Regional Atmospheric Modeling

Abstract. We describe an estimation technique for biomass burning emissions in South America based on a combination of remote sensing fire products and field observations. For each fire pixel detected by remote sensing, the mass of the emitted tracer is calculated based on field observations of fire properties related to the type of vegetation burning. The burnt area is estimated from the instantaneous fire size retrieved by remote sensing, when available, or from statistical properties of the burn scars. The sources are then spatially and temporally distributed and assimilated daily by the Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS) in order to perform the prognostic of related tracer concentrations. Two other biomass burning inventories are simultaneously used to compare the emission strength in terms of the resultant tracer distribution. Several evaluations of the model with the three emission estimations were performed, comparing results with direct measurements of carbon monoxide both near-surface and airborne, as well as remote sensing derived products. Model results with the methodology of estimation introduced in this paper show a relatively good agreement with the direct measurements and MOPITT data product; pointing out the reliability of the model from local to regional scales.

Analysis of field observations of tracer transport in a fractured till

2001 ◽  
Vol 47 (1) ◽  
pp. 29-51 ◽  
Author(s):  
Georg Kosakowski ◽  
Brian Berkowitz ◽  
Harvey Scher
Keyword(s):  
Field Observations ◽  
Tracer Transport

scholarly journals Sensitivity analysis of fracture scattering

Geophysics ◽  
2013 ◽  
Vol 78 (1) ◽  
pp. T1-T10 ◽  
Author(s):  
Xinding Fang ◽  
Michael Fehler ◽  
Tianrun Chen ◽  
Daniel Burns ◽  
Zhenya Zhu
Keyword(s):  
Surface Effect ◽  
Scattering Amplitude ◽  
Incident Angle ◽  
Elastic Response ◽  
Single Fracture ◽  
Field Observations ◽  
Slip Boundary ◽  
Explosive Source ◽  
Fracture Height ◽  
2D And 3D

We use 2D and 3D finite-difference modeling to numerically calculate the seismic response of a single finite fracture with a linear-slip boundary in a homogeneous elastic medium. We use a point explosive source and ignore the free surface effect, so the fracture scattered wavefield contains two parts: P-to-P scattering and P-to-S scattering. The elastic response of the fracture is described by the fracture compliance. We vary the incident angle and fracture compliance within a range considered appropriate for field observations and investigate the P-to-P and P-to-S scattering patterns of a single fracture. P-to-P and P-to-S fracture scattering patterns are sensitive to the ratio of normal to tangential fracture compliance and incident angle, whereas the scattering amplitude is proportional to the compliance, which agrees with the Born scattering analysis. We find that, for a vertical fracture, if the source is located at the surface, most of the energy scattered by the fracture propagates downwards. We also study the effect of fracture height on the scattering pattern and scattering amplitude.

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