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1. Risk Assessment and Mitigation Tools

Author

Hurtado, A., Eguilior, S., Rodrigo-Naharro, J., Ma, L., Recreo, F., Oluyemi, Gbenga, Editor-in-Chief, Kalantari-Dahaghi, Amirmasoud, Series Editor, Shahkarami, Alireza, Series Editor, Fernø, Martin, Series Editor, de Dios, J. Carlos, editor, Mishra, Srikanta, editor, Poletto, Flavio, editor, and Ramos, Alberto, editor

Published
2021
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4. Overview of TJ-II flexible heliac results

Author

Ascası́bar, E, Alejaldre, C, Alonso, J, Almoguera, L, Baciero, A, Balbı́n, R, Blaumoser, M, Botija, J, Brañas, B, de la Cal, E, Cappa, A, Castellano, J, Carrasco, R, Castejón, F, Cepero, J.R, Cremy, C, Doncel, J, Eguilior, S, Estrada, T, Fernández, A, Fuentes, C, Garcı́a, A, Garcı́a-Cortés, I, Guasp, J, Herranz, J, Hidalgo, C, Jiménez, J.A, Kirpitchev, I, Krivenski, V, Labrador, I, Lapayese, F, Likin, K, Liniers, M, López-Fraguas, A, López-Sánchez, A, de la Luna, E, Martı́n, R, Martı́nez-Laso, L, Medrano, M, Méndez, P, McCarthy, K.J, Medina, F, van Milligen, B, Ochando, M, Pacios, L, Pastor, I, Pedrosa, M.A, de la Peña, A, Portas, A, Qin, J, Rodrı́guez-Rodrigo, L, Romero, J, Salas, A, Sánchez, E, Sánchez, J, Tabarés, F, Tafalla, D, Tribaldos, V, Vega, J, and Zurro, B

Published
2001
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5. Perturbative transport experiments on TJ-II Flexible Heliac

Author

Castejón, F., Ascasíbar, E., Alejaldre, C., Alonso, J., Almoguera, L., Baciero, A., Balbín, R., Blanco, E., Blaumoser, M., Botija, J., Brañas, B., Cappa, A., Carrasco, R., Cepero, J.R., Chmyga, A.A., Doncel, J., Dreval, N.B., Eguilior, S., Eliseev, L., Estrada, T., Fedyanin, O., Fernández, A., Fontdecaba, J.M., Fuentes, C., García, A., García-Cortés, I., Gonçalves, B., Guasp, J., Herranz, J., Hidalgo, A., Hidalgo, C., Jiménez, J.A., Kirpitchev, I., Khrebtov, S.M., Komarov, A.D., Kozachok, A.S., Krupnik, L., Lapayese, F., Likin, K., Liniers, M., López-Bruna, D., López-Fraguas, A., López-Rázola, J., López-Sánchez, A., de la Luna, E., Malaquias, A., Martín, R., Medrano, M., Melnikov, A.V., Méndez, P., McCarthy, K.J., Medina, F., van Milligen, B., Nedzelskiy, I.S., Ochando, M., Pacios, L., Pastor, I., Pavlov, S.S., Pedrosa, M.A., de la Peña, A., Petrov, A., Petrov, S., Portas, A., Romero, J., Rodríguez-Rodrigo, L., Salas, A., Sánchez, E., Sánchez, J., Sarksian, K., Schchepetov, S., Skvortsova, N., Tabarés, F., Tafalla, D., Tribaldos, V., Varandas, C.F.A., Vega, J., and Zurro, B.

Subjects
Magnetic confinement
Abstract

Transport properties of TJ-II are explored performing perturbative experiments and taking advantage of TJ-II flexibility. Rotational transform can be varied in a wide range, which allows one to introduce low order rationals and to study their effect on transport. On the other hand, confinement properties can be studied at very different rotational transform values and for different values of magnetic shear: Experiments on influence of the magnetic shear on confinement are reported. In these cases a Ohmic current has been induced in TJ-II plasma to modify magnetic shear and to evaluate itsd effect on confinement, showing that negative shear improves the confinement. Heat transport is also reduced by locating a low order rational near the power deposition profile. Plasma potential profiles have been recently measured in some configurations up to the plasma core with the Heavy Ion Beam Probe (HIBP) diagnostic and the electric field values measured in low-density plasmas are consistent with neoclassical calculations near the plasma core. Plasma edge turbulent transport has been studied in configurations that are marginally stable due to decreased magnetic well. Results show a dynamical coupling between gradients and turbulent transport. Finally, cold pulse propagation has been studied showing ballistic non diffusive propagation.

Published
2002

6. Latest physics results of TJ-II flexible heliac

Author

Castejón, F., Alejaldre, C., Alonso, J., Almoguera, L., Ascasíbar, E., Baciero, A., Balbín, R., Blaumoser, M., Botija, J., Brañas, B., de la Cal, E., Cappa, A., Carrasco, R., Cepero, J.R., Cremy, C., Doncel, J., Eguilior, S., Estrada, T., Fernández, A., Fuentes, C., García, A., García-Cortés, I., Guasp, J., Herranz, J., Hidalgo, C., Jiménez, J.A., Kirpitchev, I., Krivenski, V., Labrador, I., Lapayese, F., Likin, K., Liniers, M., López-Fraguas, A., López-Sánchez, A., de la Luna, E., Martín, R., Martínez-Laso, L., Medrano, M., Méndez, P., McCarthy, K.J., Medina, F., van Milligen, B., Ochando, M., Pacios, L., Pastor, I., Pedrosa, M.A., de la Peña, A., Portas, A., Qin, J., Rodríguez-Rodrigo, L., Salas, A., Sánchez, E., Sánchez, J., Tabarés, F., Tafalla, D., Tribaldos, V., Vega, J., and Zurro, B.

Subjects
Magnetic confinement
Abstract

This paper is devoted to the presentation of the most relevant recent Physics results obtained in the TJ-II flexible heliac. Firstly ECRH modulation and plasma breakdown studies are summarised; then the particle control techniques used to obtain reproducible discharges with density under control are presented. Transport studies show internal heat transport barriers that reduce heat conductivity to neoclassical values, and ELM-like transport events, similar to those observed in tokamaks and in other stellarators before and during H mode transition. Evidence of ExB sheared has been observed both in the proximity of rational surfaces. Finally, a high resolution Thomsom Scattering system has shown Te and ne profile structures.

Published
2000

9. Overview of TJ-II experiments

Author

Sánchez, J., primary, Acedo, M., additional, Alonso, A., additional, Alonso, J., additional, Alvarez, P., additional, de Aragón, F., additional, Ascasíbar, E., additional, Baciero, A., additional, Balbín, R., additional, Barrera, L., additional, Blanco, E., additional, Botija, J., additional, Brañas, B., additional, de la Cal, E., additional, Calderón, E., additional, Calvo, I., additional, Cappa, A., additional, Carmona, J.A., additional, Carreras, B.A., additional, Carrasco, R., additional, Castejón, F., additional, Catalán, G., additional, Chmyga, A.A., additional, Dreval, N.B., additional, Chamorro, M., additional, Eguilior, S., additional, Encabo, J., additional, Eliseev, L., additional, Estrada, T., additional, Fernández, A., additional, Fernández, R., additional, Ferreira, J.A., additional, Fontdecaba, J.M., additional, Fuentes, C., additional, de la Gama, J., additional, García, A., additional, García, L., additional, García-Cortés, I., additional, García-Regaña, J.M., additional, Gonçalves, B., additional, Guasp, J., additional, Herranz, J., additional, Hidalgo, A., additional, Hidalgo, C., additional, Jiménez-Gómez, R., additional, Jiménez, J.A., additional, Jiménez, D., additional, Kirpitchev, I., additional, Komarov, A.D., additional, Kozachok, A.S., additional, Krupnik, L., additional, Lapayese, F., additional, Liniers, M., additional, López-Bruna, D., additional, López-Fraguas, A., additional, López-Rázola, J., additional, López-Sánchez, A., additional, de la Luna, E., additional, Marcon, G., additional, Martín, F., additional, Martínez-Fresno, L., additional, McCarthy, K.J., additional, Medina, F., additional, Medrano, M., additional, Melnikov, A.V., additional, Méndez, P., additional, Mirones, E., additional, van Milligen, B., additional, Nedzelskiy, I.S., additional, Ochando, M., additional, Olivares, J., additional, Orozco, R., additional, Ortiz, P., additional, de Pablos, J.L., additional, Pacios, L., additional, Pastor, I., additional, Pedrosa, M.A., additional, de la Peña, A., additional, Pereira, A., additional, Pérez-Risco, D., additional, Petrov, A., additional, Petrov, S., additional, Portas, A., additional, Rapisarda, D., additional, Ríos, L., additional, Rodríguez, C., additional, Rodríguez-Rodrigo, L., additional, Rodríguez-Solano, E., additional, Romero, J., additional, Ros, A., additional, Salas, A., additional, Sánchez, E., additional, Sánchez, M., additional, Sánchez-Sarabia, E., additional, Sarasola, X., additional, Sarksian, K., additional, Silva, C., additional, Schchepetov, S., additional, Skvortsova, N., additional, Soleto, A., additional, Tabarés, F., additional, Tafalla, D., additional, Tera, J., additional, Tolkachev, A., additional, Tribaldos, V., additional, Vargas, V.I., additional, Vega, J., additional, Velasco, G., additional, Weber, M., additional, Wolfers, G., additional, Zweben, S.J., additional, and Zurro, B., additional

Published
2007
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11. Overview of TJ-II experiments

Author

Hidalgo, C, primary, Alejaldre, C, additional, Alonso, A, additional, Alonso, J, additional, Almoguera, L, additional, Aragón, F. de, additional, Ascasíbar, E, additional, Baciero, A, additional, Balbín, R, additional, Blanco, E, additional, Botija, J, additional, Brañas, B, additional, Calderón, E, additional, Cappa, A, additional, Carmona, J.A, additional, Carrasco, R, additional, Castejón, F, additional, Cepero, J.R, additional, Chmyga, A.A, additional, Doncel, J, additional, Dreval, N.B, additional, Eguilior, S, additional, Eliseev, L, additional, Estrada, T, additional, Ferreira, J.A, additional, Fernández, A, additional, Fontdecaba, J.M, additional, Fuentes, C, additional, García, A, additional, García-Cortés, I, additional, Gonçalves, B, additional, Guasp, J, additional, Herranz, J, additional, Hidalgo, A, additional, Jiménez, R, additional, Jiménez, J.A, additional, Jiménez-Rey, D, additional, Kirpitchev, I, additional, Khrebtov, S.M, additional, Komarov, A.D, additional, Kozachok, A.S, additional, Krupnik, L, additional, Lapayese, F, additional, Liniers, M, additional, López-Bruna, D, additional, López-Fraguas, A, additional, López-Rázola, J, additional, López-Sánchez, A, additional, Luna, E. de la, additional, Marcon, G, additional, Martín, R, additional, McCarthy, K.J, additional, Medina, F, additional, Medrano, M, additional, Melnikov, A.V, additional, Méndez, P, additional, Milligen, B. van, additional, Nedzelskiy, I.S, additional, Ochando, M, additional, Orozco, O, additional, Pablos, J.L. de, additional, Pacios, L, additional, Pastor, I, additional, Pedrosa, M.A, additional, Peña, A. de la, additional, Pereira, A, additional, Petrov, A, additional, Petrov, S, additional, Portas, A, additional, Rapisarda, D, additional, Rodríguez-Rodrigo, L, additional, Rodríguez-Solano, E, additional, Romero, J, additional, Salas, A, additional, Sánchez, E, additional, Sánchez, J, additional, Sánchez, M, additional, Sarksian, K, additional, Silva, C, additional, Schchepetov, S, additional, Skvortsova, N, additional, Tabarés, F, additional, Tafalla, D, additional, Tolkachev, A, additional, Tribaldos, V, additional, Vargas, I, additional, Vega, J, additional, Wolfers, G, additional, and Zurro, B, additional

Published
2005
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14. Confinement and stability on the TJ-II stellarator

Author

Ascas bar, E, primary, Alejaldre, C, additional, Alonso, J, additional, Almoguera, L, additional, Baciero, A, additional, Balb n, R, additional, Blanco, E, additional, Blaumoser, M, additional, Botija, J, additional, Bra as, B, additional, Cappa, A, additional, Carrasco, R, additional, Castej n, F, additional, Cepero, J R, additional, Chmyga, A A, additional, Doncel, J, additional, Dreval, N B, additional, Eguilior, S, additional, Eliseev, L, additional, Estrada, T, additional, Fedyanin, O, additional, Fern ndez, A, additional, Fontdecaba, J M, additional, Fuentes, C, additional, Garc a, A, additional, Garc a-Cort s, I, additional, Gon alves, B, additional, Guasp, J, additional, Herranz, J, additional, Hidalgo, A, additional, Hidalgo, C, additional, Jim nez, J A, additional, Kirpitchev, I, additional, Khrebtov, S M, additional, Komarov, A D, additional, Kozachok, A S, additional, Krupnik, L, additional, Lapayese, F, additional, Likin, K, additional, Liniers, M, additional, L pez-Bruna, D, additional, L pez-Fraguas, A, additional, L pez-R zola, J, additional, L pez-S nchez, A, additional, Luna, E de la, additional, Malaquias, A, additional, Mart n, R, additional, Medrano, M, additional, Melnikov, A V, additional, M ndez, P, additional, McCarthy, K J, additional, Medina, F, additional, Milligen, B van, additional, Nedzelskiy, I S, additional, Ochando, M, additional, Pacios, L, additional, Pastor, I, additional, Pedrosa, M A, additional, Pe a, A de la, additional, Petrov, A, additional, Petrov, S, additional, Portas, A, additional, Romero, J, additional, Rodr guez-Rodrigo, L, additional, Salas, A, additional, S nchez, E, additional, S nchez, J, additional, Sarksian, K, additional, Schchepetov, S, additional, Skvortsova, N, additional, Tabar s, F, additional, Tafalla, D, additional, Tribaldos, V, additional, Varandas, C F A, additional, Vega, J, additional, and Zurro, B, additional

Published
2002
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15. Transport Properties in the TJ-II Flexible Heliac.

Author

Castejón, F., Ascasíbar, E., Alejaldre, C., Alonso, J., Almoguera, L., Baciero, A., Balbín, R., Blanco, E., Blaumoser, M., Botija, J., Brañas, B., Cappa, A., Carrasco, R., Cepero, J. R., Chmyga, A. A., Doncel, J., Dreval, N. B., Eguilior, S., and Eliseev, L.

Subjects
PLASMA density, PLASMA gases, HEAVY ions, PLASMA turbulence, SHEAR flow
Abstract

TJ-II flexibility is exploited to perform an investigation on the transport properties of this device. Rotational transform can be varied in a wide range, which allows one to introduce low order rationals and to study their effect on transport. On the other hand, confinement properties can be studied at very different rotational transform values and for different values of magnetic shear: Experiments on influence of the magnetic shear on confinement are reported. Plasma potential profiles have been recently measured in some configurations up to the plasma core with the Heavy Ion Beam Probe (HIBP) diagnostic and the electric field values measured in low-density plasmas are consistent with neoclassical calculations near the plasma core. Plasma edge turbulent transport has been studied in configurations that are marginally stable due to decreased magnetic well. Results show a dynamical coupling between gradients and turbulent transport. [ABSTRACT FROM AUTHOR]

Published
2003

16. Review of confinement and transport studies in the TJ-II flexible heliac

Author

Alejaldre, C., primary, Almoguera, L., additional, Alonso, J., additional, Ascasíbar, E., additional, Baciero, A., additional, Balbín, R., additional, Blaumoser, M., additional, Botija, J., additional, Brañas, B., additional, Cal, E. de la, additional, Cappa, A., additional, Carrasco, R., additional, Castejón, F., additional, Castellano, J., additional, Cepero, J.R., additional, Cremy, C., additional, Doncel, J., additional, Eguilior, S., additional, Estrada, T., additional, Fernández, A., additional, Fuentes, C., additional, García, A., additional, García-Cortés, I., additional, Guasp, J., additional, Herranz, J., additional, Hidalgo, C., additional, Jiménez, J.A., additional, Kirpitchev, I., additional, Krivenski, V., additional, Labrador, I., additional, Lapayese, F., additional, Likin, K., additional, Liniers, M., additional, López-Fraguas, A., additional, López-Sánchez, A., additional, Luna, E. de la, additional, Martín, R., additional, Martínez-Laso, L., additional, McCarthy, K.J., additional, Medina, F., additional, Medrano, M., additional, Méndez, P., additional, Milligen, B. van, additional, Ochando, M., additional, Pacios, L., additional, Pastor, I., additional, Pedrosa, M.A., additional, Peña, A. de la, additional, Portas, A., additional, Qin, J., additional, Rodríguez-Rodrigo, L., additional, Romero, J., additional, Salas, A., additional, Sánchez, E., additional, Sánchez, J., additional, Tabarés, F., additional, Tafalla, D., additional, Tribaldos, V., additional, Vega, J., additional, and Zurro, B., additional

Published
2001
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17. Langevin equations for quasi-linear wave–particle interaction

Author

Castejón, F and Eguilior, S

Abstract

The Langevin equations for quasi-linear wave–particle interaction are obtained taking advantage of the unequivocal equivalence between the Fokker–Planck equation and the former ones. The Langevin equations are solved numerically and, hence, the evolution of a single particle embedded in an electromagnetic field in momentum space is obtained. The equations are relativistic and valid for any wave. It is also shown that the stochastic part of the equations is negligible in comparison with the deterministic term, except for the momentum close to the resonance condition for the main parallel refractive index.

Published
2003

18. Confinement and stability on the TJ-II stellarator

Author

Ascasíbar, E, Alejaldre, C, Alonso, J, Almoguera, L, Baciero, A, Balbín, R, Blanco, E, Blaumoser, M, Botija, J, Brañas, B, Cappa, A, Carrasco, R, Castejón, F, Cepero, J R, Chmyga, A A, Doncel, J, Dreval, N B, Eguilior, S, Eliseev, L, Estrada, T, Fedyanin, O, Fernández, A, Fontdecaba, J M, Fuentes, C, García, A, García-Cortés, I, Gonçalves, B, Guasp, J, Herranz, J, Hidalgo, A, Hidalgo, C, Jiménez, J A, Kirpitchev, I, Khrebtov, S M, Komarov, A D, Kozachok, A S, and L

Abstract

This paper describes a series of experiments performed in TJ-II stellarator with the aim of studying the influence of magnetic configuration on stability and transport properties of TJ-II plasmas. Plasma potential profiles have been measured in several configurations up to the plasma core with the heavy ion beam probe diagnostic. Low-order rational surfaces have been positioned at different plasma radii observing the effect on transport features. Plasma edge turbulent transport has been studied in configurations that are marginally stable due to decreased magnetic well. Results show a dynamical coupling between gradients and turbulent transport. Experiments on the influence of magnetic shear on confinement are reported. Global confinement issues as well as enhanced confinement regimes found in TJ-II are discussed as well.

Published
2002

21. Transport properties in the TJ-II flexible heliac

Author

Castejon, F., Ascasibar, E., Alejaldre, C., Alonso, J., Almoguera, L., Baciero, A., Balbin, R., Emilio Blanco, Blaumoser, M., Botija, J., Branas, B., Cappa, A., Carrasco, R., Cepero, Jr, Chmyga, Aa, Doncel, J., Dreval, Nb, Eguilior, S., Eliseev, L., Estrada, T., Fedyanin, O., Fernandez, A., Fuentes, C., Garcia, A., Garcia-Cortes, I., Goncalves, B., Guasp, J., Herranz, J., Hidalgo, A., Hidalgo, C., Jimenez, A., Kirpitchev, I., Khrebtov, Sm, Komarov, Ad, Kozachok, As, Krupnik, L., Lapayese, F., Likin, K., Liniers, M., Lopez-Bruna, D., Lopez-Fraguas, A., Lopez-Razola, J., Lopez-Sanchez, A., La Luna, E., Malaquias, A., Martin, R., Medrano, M., Melnikov, Av, Mendez, P., Mccarthy, Kj, Medina, F., Milligen, B., Nedzelskiy, Is, Ochando, M., Pacios, L., Pastor, I., Pedrosa, Ma, La Pena, A., Petrov, A., Portas, A., Romero, J., Rodriguez-Rodrigo, L., Salas, A., Sanchez, E., Sanchez, J., Sarksian, K., Schchepetov, S., Skvortsova, N., Tabares, F., Tafalla, D., Tribaldos, V., Varandas, Cfa, Vega, J., Zurro, B., Falconer, Is, Dewar, Rl, and Khachan, J.

23. Acute and chronic risk assessment of BTEX in the return water of hydraulic fracturing operations in Marcellus Shale.

Author

Ma L, Hurtado A, Eguilior S, and Llamas Borrajo JF

Subjects
Humans, Natural Gas analysis, Water, Wastewater, Risk Assessment, Hydraulic Fracking, Water Pollutants, Chemical analysis
Abstract

Environmental pollution caused by human activities is a pressing issue in developed countries. In this context, it is vital to establish methodologies for the early and reliable estimation of the health risks posed by potential pollutants. Flowback and produced water (return water) from shale gas operations can contain toxic compounds, of which BTEX (benzene, toluene, ethylbenzene, and xylenes) are of concern due to their toxicity and frequent presence above regulatory limits. The return water generated by these operations is stored in ponds or tanks before reaching its final destination. Over time, the composition of this water changes, and leaks or inadequate contact can harm the environment and human health. Here we developed a risk assessment framework to evaluate the temporal evolution of chronic and acute BTEX exposure risks caused by accidental return water leakage. We applied the approach to a hydraulic fracturing operation in the Marcellus Shale Formation. Starting with a time series of BTEX concentrations in the return water, our method deploys transport models to assess risk to health. Our approach compares exposure levels with regulatory limits for inhalation, ingestion, and dermal contact. By identifying the risk levels, exposure pathways, and control parameters in the case study for a range of periods after leakage, our study supports the implementation of appropriate risk mitigation strategies. In addition, by examining risk variation under arid, semi-arid, and humid climate scenarios, the study reveals the impact of climate change on soil characteristics and BTEX transport. The development and application of this methodology is an important step in addressing concerns regarding shale gas operations. The approach proposed paves the way for sustainable practices that prioritise the protection of human health and the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Published
2024
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24. Exposure risk assessment to organic compounds based on their concentrations in return water from shale gas developments.

Author

Ma L, Hurtado A, Eguilior S, and Llamas Borrajo JF

Subjects
Humans, Natural Gas analysis, Risk Assessment, Wastewater analysis, Water analysis, Hydraulic Fracking, Volatile Organic Compounds analysis
Abstract

Because of shale gas operations, significant amounts of return water from hydraulic fracturing are stored in tanks and/or ponds on the surface. These waters contain varying concentrations of toxic organic compounds; hence, there is reasonable concern about the occurrence of hypothetical leakages, which would cause adverse environmental effects and pose a risk to human health. In this study, the chronic and acute carcinogenic and non-carcinogenic risks from exposure to these pollutants by inhalation, ingestion and dermal contact have been assessed for an affected area. The first part of this study focused on estimating the concentrations of organic compounds in the water-soil-atmosphere system. These models are of a general nature and can be applied to any site. In this study, they are applied to the Marcellus shale formation. The analyses developed in this work show that the risks - both carcinogenic and non-carcinogenic - regarding the inhalation of volatile organic compounds (VOCs) increase rapidly and exceed the acceptable thresholds by several orders of magnitude in all scenarios, irrespective of the different recharge rates considered. Given that the hypothetical leakage under consideration occurs at a depth of 50 cm, in the buried part of a semi-buried tank-type reservoir, the direct contamination via wastewater of the most superficial parts of the soil is less likely, and soil particles are generally widely dispersed in air before inhaling. Moreover, the sensitivity analysis indicated that the variable contributing the most to the determined risk levels was the pollutant concentration, followed by the exposure time. Therefore, using appropriate technology to reduce pollutant concentrations in storage ponds is the best strategy to minimise the associated risk to human health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Published
2022
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25. Forecasting concentrations of organic chemicals in the vadose zone caused by spills of hydraulic fracturing wastewater.

Author

Ma L, Hurtado A, Eguilior S, and Llamas Borrajo JF

Abstract

The return water from hydraulic fracturing operations is characterised by high concentrations of salts and toxic organic compounds. This water is stored on the surface in storage tanks and/or ponds. Wastewater spills caused by inappropriate storage can lead to the contamination of various environmental compartments, thus posing a risk to human health. Such risk can be determined by estimating the concentrations of the substances in the storage system and the behaviour of the same in function of the characteristics of the environment in which they are released. To this end, here we addressed the evolution of the concentrations of pollutants in a tank used to store wastewater from hydraulic fracturing operations. To do this, we estimated both the volume of flowback and the concentrations of the pollutants found in these waters. We then examined the dynamic behaviour of spill-derived compounds in the various environmental compartments in function of the conditions of the medium (humid, semi-arid, and arid). This approach allowed us to rank the hazard posed by the chemical compounds in question, as well as to determine those parameters associated with both the compounds and external natural conditions that contribute to environmental risk. Our results shed greater light on the mechanism by which external environmental variables (especially recharge rate) influence the migration of organic compounds in the vadose zone, and contribute to the prediction of their concentrations. Also, by estimating the time that chemicals remain in contaminated areas, we identify the phases of contamination that pose the greatest risk to human health. In summary, the approach used herein allows the ranking of compounds on the basis of risk to human health and can thus facilitate the design of pollutant management strategies. Of note, our ranked list highlights the relevance of benzene., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Published
2019
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26. A model for predicting organic compounds concentration change in water associated with horizontal hydraulic fracturing.

Author

Ma L, Hurtado A, Eguilior S, and Llamas Borrajo JF

Abstract

Horizontal drilling and hydraulic fracturing are technologies designed to increase natural gas flow and to improve productivity in low permeability formations. During this drilling operation, tons of flowback and produced water, which contain several organic compounds, return to the surface with a potential risk of influencing the surrounding environment and human health. In order to conduct predictive risk assessments a mathematical model is needed to evaluate organic compound behaviour along the water transportation process as well as concentration changes over time throughout the operational life cycle. A comprehensive model, which fits the experimental data, combining an Organic Matter Transport Dynamic Model with a Two-Compartment First-order Rate Constant (TFRC) Model has been established to quantify the organic compounds concentrations. This algorithm model incorporates two transportation rates, fast and slow. The results show that the higher the value of the organic carbon partition coefficient (k oc ) in chemicals, the later the maximum concentration in water will be reached. The maximum concentration percentage would reach up to 90% of the available concentration of each compound in shale formation (whose origin may be associated to drilling fluid, connate water and/or rock matrix) over a sufficiently long period of time. This model could serve as a contribution to enhance monitoring strategy, increase benefits out of optimizing health risk assessment for local residents and provide initial baseline data to further operations., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Published
2018
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27. A risk assessment tool applied to the study of shale gas resources.

Author

Veiguela M, Hurtado A, Eguilior S, Recreo F, Roqueñi N, and Loredo J

Subjects
Hydraulic Fracking, Risk Assessment methods, Spain, Energy-Generating Resources, Environmental Monitoring methods, Natural Gas analysis
Abstract

The implementation of a risk assessment tool with the capacity to evaluate the risks for health, safety and the environment (HSE) from extraction of non-conventional fossil fuel resources by the hydraulic fracturing (fracking) technique can be a useful tool to boost development and progress of the technology and winning public trust and acceptance of this. At the early project stages, the lack of data related the selection of non-conventional gas deposits makes it difficult the use of existing approaches to risk assessment of fluids injected into geologic formations. The qualitative risk assessment tool developed in this work is based on the approach that shale gas exploitation risk is dependent on both the geologic site and the technological aspects. It follows from the Oldenburg's 'Screening and Ranking Framework (SRF)' developed to evaluate potential geologic carbon dioxide (CO2) storage sites. These two global characteristics: (1) characteristics centered on the natural aspects of the site and (2) characteristics centered on the technological aspects of the Project, have been evaluated through user input of Property values, which define Attributes, which define the Characteristics. In order to carry out an individual evaluation of each of the characteristics and the elements of the model, the tool has been implemented in a spreadsheet. The proposed model has been applied to a site with potential for the exploitation of shale gas in Asturias (northwestern Spain) with tree different technological options to test the approach., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Published
2016
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