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Volume 31 Issue 1
Jan.  2020
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Monika Wójcik, Wojciech Kostowski. Environmental Risk Assessment for Exploration and Extraction Processes of Unconventional Hydrocarbon Deposits of Shale Gas and Tight Gas: Pomeranian and Carpathian Region Case Study as Largest Onshore Oilfields. Journal of Earth Science, 2020, 31(1): 215-222. doi: 10.1007/s12583-020-1263-4
Citation: Monika Wójcik, Wojciech Kostowski. Environmental Risk Assessment for Exploration and Extraction Processes of Unconventional Hydrocarbon Deposits of Shale Gas and Tight Gas: Pomeranian and Carpathian Region Case Study as Largest Onshore Oilfields. Journal of Earth Science, 2020, 31(1): 215-222. doi: 10.1007/s12583-020-1263-4

Environmental Risk Assessment for Exploration and Extraction Processes of Unconventional Hydrocarbon Deposits of Shale Gas and Tight Gas: Pomeranian and Carpathian Region Case Study as Largest Onshore Oilfields

doi: 10.1007/s12583-020-1263-4
More Information
  • Shale gas and tight gas exploration and extraction processes create potential threats to the environment. In Poland, no comprehensive guidelines for environmental risk assessment have been prepared so far. This paper presents a proposal of environmental risk assessment methodology which can be used for corporate risk management procedures during exploration and extraction of unconventional hydrocarbons in Poland. The most frequent environmental threats that may occur during the exploration and exploitation of unconventional hydrocarbon deposits include degradation of soils through construction of drilling rigs and access roads, landforms change, local soil pollution caused by fuels, cleaning agents and materials used to prepare drilling fluids, rubble, cement, gravel, pollution of surface and underground water as a result of emergency discharges of sewage, infiltration of pollution from waste reservoirs, disturbance of hydrogeological equilibrium through significant water intake, noise and atmospheric pollution resulting from the combustion of fuels. To check the level of these threats' six exploration sites form Pomeranian and Carpathian region of Poland (3 wells of shale gas and 3 wells of tight gas) have been evaluated in detail, and the risk quantification has been made. Because of a local, short-term and reversible environment impact, the environmental risks for the exploration and extraction processes of unconventional hydrocarbons have been found to be medium or negligibly small. It is recommended that using the same methodology for other regions of Poland where we can find unconventional hydrocarbons and it can be enriched in dedicated application with spatial maps to give the investors a quick feedback on the potential environmental risks.
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  • Baisch, S., Pater, C. J., 2011. Geomechanical Study of Bowland Shale Seismicity. Synthesis Report, 11/2011. Warszawa
    Beer, T., Ziolkowski, F., 2013. Environmental Risk Assessment: An Australian Perspective. EPA, Sydney
    Borysiewicz, M., Kacprzyk, W., Potempski, S., et al., 2005. Wytyczne Oceny Ryzyka Środowiskowego, IOŚ Warszawa
    Dinca, C., Rousseaux, P., Badea, A., 2007. A Life Cycle Impact of the Natural Gas Used in the Energy Sector in Romania. Journal of Cleaner Production, 15(15): 1451-1462. https://doi.org/10.1016/j.jclepro.2006.03.011 doi:  10.1016/j.jclepro.2006.03.011
    Gao, X. H., Dong, G. W. A., Liu, B. L., et al., 2018. Groundwater Environmental Impact and Supervise Recommendation in Process of Shale Gas Development in China. IOP Conference Series: Earth and Environmental Science, 191: 012047. https://doi.org/10.1088/1755-1315/191/1/012047 doi:  10.1088/1755-1315/191/1/012047
    Gasińki, T., Pijanowski, S., 2011. Zarzązanie Ryzykiem Procesie Zrónoważnego Rozwoju Biznesu, Ministerstwo Gospodarki. Warszawa
    Gormley, A., Pollard, S., Rocks, S., 2011. Guidelines for Environmental Risk Assessment and Management Green Leaves Ⅲ. Defra, UK
    Góski, M., 2009. Rynkowy System Finansowy. PWN, Warszawa
    Macuda, J., 2010. Środowiskowe Aspekty Produkcji Gazu Ziemnegoz Niekonwencjonalnych Złóż. Przeglą Geologiczny, 58: 266-270
    Meadows, D. H., Meadows, D. L., Randers, J., et al., 1973. Granice Wzrostu, Pańtwowe Wydawnictwo Ekonomiczne. PWN, Warszawa
    Ministry of Environment, Lands and Parks, 2000. Environmental Risk Assessment (ERA): An Approach for Assessing and Reporting Environmental Conditions, Technical Bulletin 1. British Columbia
    Plesiewicz, B., Suchcicki, J., Wiszniowski, J., 2011. Monitoring Sejsmiczny Szczelinowania Hydraulicznegona Otworze Łebień LE-2H, NFOŚiGW. Instytut Geofizyki PAN, Warszawa
    Polish Geological Institute-National Research Institute, 2011. Badania Aspektó Środowiskowych Procesu Szczelinowania Hydraulicznego Wykonanego Wotworze Łebień LE-2H, PIG-PIB. Warszawa
    Riva, A., D'Angelosante, S., Trebeschi, C., 2006. Natural Gas and the Environmental Results of Life Cycle Assessment. Energy, 31(1): 138-148. https://doi.org/10.1016/j.energy.2004.04.057 doi:  10.1016/j.energy.2004.04.057
    Sapkota, K., Oni, A. O., Kumar, A., 2018. Techno-Economic and Life Cycle Assessments of the Natural Gas Supply Chain from Production Sites in Canada to North and Southwest Europe. Journal of Natural Gas Science and Engineering, 52: 401-409. https://doi.org/10.1016/j.jngse.2018.01.048 doi:  10.1016/j.jngse.2018.01.048
    Stamford, L., Azapagic, A., 2014. Life Cycle Environmental Impacts of UK Shale Gas. Applied Energy, 134: 506-518. https://doi.org/10.1016/j.apenergy.2014.08.063 doi:  10.1016/j.apenergy.2014.08.063
    Sun, Y. Q., Wang, D., Tsang, D. C. W., et al., 2019. A Critical Review of Risks, Characteristics, and Treatment Strategies for Potentially Toxic Elements in Wastewater from Shale Gas Extraction. Environment International, 125: 452-469. https://doi.org/10.1016/j.envint.2019.02.019 doi:  10.1016/j.envint.2019.02.019
    US Environmental Protection Agency (US EPA), 1992. Framework for Ecological Risk Assessment. Washington DC
    US Environmental Protection Agency (US EPA), 1998. Guidelines for Ecological Risk Assessment. Washington DC
    Westaway, R., Younger, P. L., Cornelius, C., 2015. Comment on "Life Cycle Environmental Impacts of UK Shale Gas". Applied Energy, 148: 489-495. https://doi.org/10.1016/j.apenergy.2015.03.008 doi:  10.1016/j.apenergy.2015.03.008
    Yu, C.-H., Huang, S.-K., Qin, P., et al., 2018. Local Residents'Risk Perceptions in Response to Shale Gas Exploitation: Evidence from China. Energy Policy, 113: 123-134. https://doi.org/10.1016/j.enpol.2017.10.004 doi:  10.1016/j.enpol.2017.10.004
    Zhang, D. X., Yang, T. Y., 2015. Environmental Impacts of Hydraulic Fracturing in Shale Gas Development in the United States. Petroleum Exploration and Development, 42(6): 876-883. https://doi.org/10.1016/s1876-3804(15)30085-9 doi:  10.1016/s1876-3804(15)30085-9
    Zhang, N. Y., Zhang, Z., Rui, Z. H., et al., 2018. Comprehensive Risk Assessment of High Sulfur-Containing Gas Well. Journal of Petroleum Science and Engineering, 170: 888-897. https://doi.org/10.1016/j.petrol.2018.07.016 doi:  10.1016/j.petrol.2018.07.016
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Environmental Risk Assessment for Exploration and Extraction Processes of Unconventional Hydrocarbon Deposits of Shale Gas and Tight Gas: Pomeranian and Carpathian Region Case Study as Largest Onshore Oilfields

doi: 10.1007/s12583-020-1263-4
    Corresponding author: Monika Wójcik

Abstract: Shale gas and tight gas exploration and extraction processes create potential threats to the environment. In Poland, no comprehensive guidelines for environmental risk assessment have been prepared so far. This paper presents a proposal of environmental risk assessment methodology which can be used for corporate risk management procedures during exploration and extraction of unconventional hydrocarbons in Poland. The most frequent environmental threats that may occur during the exploration and exploitation of unconventional hydrocarbon deposits include degradation of soils through construction of drilling rigs and access roads, landforms change, local soil pollution caused by fuels, cleaning agents and materials used to prepare drilling fluids, rubble, cement, gravel, pollution of surface and underground water as a result of emergency discharges of sewage, infiltration of pollution from waste reservoirs, disturbance of hydrogeological equilibrium through significant water intake, noise and atmospheric pollution resulting from the combustion of fuels. To check the level of these threats' six exploration sites form Pomeranian and Carpathian region of Poland (3 wells of shale gas and 3 wells of tight gas) have been evaluated in detail, and the risk quantification has been made. Because of a local, short-term and reversible environment impact, the environmental risks for the exploration and extraction processes of unconventional hydrocarbons have been found to be medium or negligibly small. It is recommended that using the same methodology for other regions of Poland where we can find unconventional hydrocarbons and it can be enriched in dedicated application with spatial maps to give the investors a quick feedback on the potential environmental risks.

Monika Wójcik, Wojciech Kostowski. Environmental Risk Assessment for Exploration and Extraction Processes of Unconventional Hydrocarbon Deposits of Shale Gas and Tight Gas: Pomeranian and Carpathian Region Case Study as Largest Onshore Oilfields. Journal of Earth Science, 2020, 31(1): 215-222. doi: 10.1007/s12583-020-1263-4
Citation: Monika Wójcik, Wojciech Kostowski. Environmental Risk Assessment for Exploration and Extraction Processes of Unconventional Hydrocarbon Deposits of Shale Gas and Tight Gas: Pomeranian and Carpathian Region Case Study as Largest Onshore Oilfields. Journal of Earth Science, 2020, 31(1): 215-222. doi: 10.1007/s12583-020-1263-4
  • The pace of using natural resources breaks the ecological balance, and the perspective of resource depletion and severe environmental pollution is an increasing threat. The risk of a global economic breakdown as a result of the use of non-renewable resources is forecasted, among others, in the report "Limits of growth"(Meadows et al., 1973). The intensive search for alternative energy resources for the next few centuries led to the focus on gas deposits, ubiquitous in the world, so far not used on a massive scale, i.e., shale gas and tight gas.

    Every industry has an impact on the environment. The elimination of risks associated with the exploration and production of unconventional hydrocarbons is a great challenge yet it is required for the safe operation of infrastructure in the future. Rational risk management can provide managers with valuable information on the potential effects of different decisions.

  • A number of studies have been dedicated to the assessment of environmental impact related with natural gas production, transportation and utilization. Riva et al. (2006) estimated the environmental impact attributed to natural gas in a life cycle approach, their research was mainly focused on energy consumption and atmospheric emissions (including CH4, NOx, CO2, VOS and SOx) related to various sectors of natural gas industry in Italy, as well as with system effects related to natural gas-based electricity generation. Recently, Sapkota et al. (2018) conducted a more detailed LCA analysis for the oversea gas supply chain from Canada to Europe. They analyzed energy and material input related to drilling and production including the sweaten-ing and drying (dehydration) units, as well as energy/material flows in the transportation phase including liquefaction and regasification. The results were presented in a synthetic form as the so-called well-to-wire equivalent emissions expressed in g-CO2eq/MJ, mostly attributed to the end of chain, i.e., to power plants. However, the authors also conclude that there is still a high uncertainty of data related with the production stage.

    A more detailed LCA analysis was performed by Stamford and Azapagic (2014), who studied environmental impacts of shale gas extraction in the UK. The study provides detailed data on the gas production process, including the use of energy, water, materials (including the fracking fluid), related emissions, and the data are organized into the best, central and worst case scenarios. Results are also presented for the whole natural gas utilization chain including the production of electricity. Interestingly, their results have been criticized by Westaway et al. (2015) as way too pessimistic, setting shale gas below coal in the ranking of total environmental impact.

    Moreover, there is large number of descriptive studies which fail to provide any significant quantitative information, e.g., for the US (Zhang and Yang, 2015), China (Gao et al., 2018; Yu et al., 2018) and Romania (Dinca et al., 2007).

    Sun et al. (2019) provided a review of technological issues related to wastewater resulted from shale gas extraction. They provided quantitative information on components used for hydraulic fracturing and their toxicity. This information can be used for a comparison of results concerning measuring the influence of wastewater threats for shale gas and for tight gas (Table 2) in Polish conditions.

    Type: location threats (L) Exploration Production Decomissioning Exploration Production Decomissioning Exploration Production Decomissioning
    Total risk Shale gas wells risk S1–S3 Tight gas wells risk T1–T3
    L(1) Nature protection 0, 2 0, 2 0, 2 0, 0 0, 0 0, 0 0, 3 0, 3 0, 3
    L(2) Close nature protection 0, 3 0, 8 1, 0 0, 7 1, 7 2, 0 0, 0 0, 0 0, 0
    L(3) Landslides and wetlands 0, 2 1, 0 0, 2 0, 3 2, 0 0, 3 0, 0 0, 0 0, 0
    L(4) Water protection 0, 5 2, 0 0, 8 0, 7 2, 0 0, 7 0, 3 2, 0 1, 0
    L(5) Floods zone 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(6) Spa protection 0, 3 0, 3 0, 3 0, 0 0, 0 0, 0 0, 7 0, 7 0, 7
    L(7) Plants 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(8) Archeological sites 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    Type: environmental threats (E)
    E(1) Spills 0, 0 2, 2 1, 2 0, 0 2, 3 1, 3 0, 0 2, 0 1, 0
    E(2) Water intake 0, 0 3, 2 0, 0 0, 0 2, 3 0, 0 0, 0 4, 0 0, 0
    E(3) Energy intake 0, 0 1, 8 0, 0 0, 0 1, 7 0, 0 0, 0 2, 0 0, 0
    E(4) Wastewater 0, 0 2, 5 1, 8 0, 0 3, 0 1, 7 0, 0 2, 0 2, 0
    E(5) Waste 0, 0 3, 5 3, 5 0, 0 4, 0 4, 0 0, 0 3, 0 3, 0
    E(6) Radioactivity 0, 0 1, 0 0, 0 0, 0 1, 0 0, 0 0, 0 1, 0 0, 0
    E(7) Agricultural destruction 1, 2 3, 0 0, 3 1, 3 3, 0 0, 7 1, 0 3, 0 0, 0
    E(8) Noise 1, 0 2, 5 1, 0 1, 0 2, 0 1, 0 1, 0 3, 0 1, 0
    E(9) Lighting 0 1, 8 0 0, 0 1, 7 0, 0 0, 0 2, 0 0, 0
    E(10) Traffic 1, 5 3 1 2, 0 3, 0 1, 0 1, 0 3, 0 1, 0
    E(11) Vibrations 1, 5 3 0 2, 0 2, 0 0, 0 1, 0 4, 0 0, 0
    E(12) Air emissions 1 2 0, 5 1, 0 2, 0 1, 0 1, 0 2, 0 0, 0
    E(13) Water regime 0 2 0 0, 0 0, 0 0, 0 0, 0 4, 0 0, 0
    E(14) Land destruction 1, 8 2, 8 0, 3 2, 7 2, 7 0, 7 1, 0 3, 0 0, 0

    Table 2.  Risk analysis sheet (own elaboration)

    The most detailed example of risk assessment which can be used for unconventional hydrocarbons has been presented by Zhang et al. (2018), who proposed a novel calculation model of comprehensive risk matrix methods based on the qualitative and semi-quantitative analysis. The well faults and the influencing factors were analyzed, firstly. Secondly, the fuzzy comprehensive assessment framework was established to quantify the risk factors. The relative importance of the risk factors was compared using the Borda number theory, in which the key risk factors can easily be distinguished. The quantified value of the well risks and all the influence levels of well factors can be obtained. Finally, a chosen gas well was empirically investigated to verify the applicability of the method.

    Environmental risk should be part of the entire risk analysis conducted in an enterprise. Environmental risk analysis is derived from an investigation of the impact of particular substances and chemical compounds produced, used and released to the environment and their impact on humans. The first documents with regard to risk analysis have been elaborated in the US (1975) (https://www.epa.gov/risk/about-risk-assessment). In the 1980s, EPA (Environmental Protection Agency) launched the Integrated Risk Information System (IRIS)—a database of effects on human health that may arise from exposure to various substances found in the environment. According to the EPA definition (US EPA, 1992), a risk analysis is a process that determines the likelihood of adverse effects in the environment as a result of exposure of living organisms to one or more stress factors. The "Framework for ecological risk assessment" document (US EPA, 1992) further distinguishes the ecological risk analysis (i.e., chemical safety assessment, emerging hazardous waste, emissions to the environment, impact on biodiversity, landscape changes, impact on water resources) and the risk analysis for human health. The "Guidelines for Ecological Risk Assessment" document (US EPA, 1998) is an extension and update of the previous ones, which emphasizes that risk assessment and risk management are two separate activities. They consist of a risk assessment to human health and a risk assessment to the environment. The document describes human populations, resources and ecological measures, characterizes the potential for adverse effects, defines uncertainty, proposes opportunities to deal with threats and provides information about threats to people and ecosystems. The report "Environmental risk assessment: An Australian perspective"(Beer and Ziolkowski, 2013) shows that the environmental risk assessment can be used as a strategic tool in the operations of enterprises. Following this example, it is worth using the next guidelines "Enviromental risk assessment (ERA): An approach for assessing and reporting environmental conditions"(Ministry of Environment, Lands and Parks, 2000) as an aid in the assessment and reporting of environmental conditions.

    The analysis of the environmental risk should always be carried out in the form of a case study with a diagram or map of identified areas for a specific risk from the source of its creation, through migration routes to the recipient (Gormley et al., 2011).

    In the European Union regulations, risk assessment procedures have been specified in "Commission directive 93/67/EEC of July 20th 1993 on the principles of risk assessment for humans and the environment from substances admitted to trading in relation to Directive 67/548/EEC? This does not mean, however, that the guidelines only apply to chemical substances. With their help, one can also analyze the risks associated with noise emission, landscape change or water relations.

    In Poland, the way of risk assessment for human health and environment is regulated by "Act of January 11th 2001 on chemical substances and preparations" and "Regulation of the Minister of Health of January 12th, 2005 on the way of assessing the risk to human health and the environment, by new substances". Act of April 27th 2001 Environmental Protection Law does not require a risk analysis, however, it can be concluded that this analysis should form part of the environmental impact assessment. In the case of qualified plants such as the so-called increased or high risk plants (Polish formal abbreviations ZZR and ZDR, respectively), the occurrence of industrial accidents requires the operator to prepare an accident prevention program and a safety report.

    These instructions and guidebooks can be used as a starting point for risk assessment and risk management. In Poland, no comprehensive guidelines for environmental risk assessment have been prepared so far.

  • The risk accompanies man and his surroundings all the time. It can be defined as an opportunity of an event whose occurrence will have a negative impact on the achievement of the intended goal (Górski, 2009), or a measure of the likelihood of an unsatisfactory result affecting a design, process or product. It can be examined in various contexts. The exploration and production industry encounters an enormous challenge related to unconventional hydrocarbons, as many of the operations were carried out in Polish conditions for the first time. For this reason, there was no data to carry out the environmental risk analysis, which was provided by the monitoring of the initial state during and after the investment.

    According to the definition (Borysiewicz et al., 2005), Environmental risk is an actual or potential threat identified as a negative impact on living organisms and the environment resulted from the activities of a given organization. For the purpose of assessing the impact of planned exploration and exploitation works on the environment and threats that may occur on the part of specific environmental elements and people, three main stages of work can be distinguished: (1) the exploration and recognition phase, (2) the industrial gas extraction phase and (3) the end-of-operation phase. The most frequent environmental threats that may occur during the exploration and exploitation of unconventional hydrocarbon deposits include: Polish Geological Institute-National Research Institute (2011), Baisch and Pater (2011), Macuda (2010), Plesiewicz et al. (2011): degradation of soils through construction of drilling rigs and access roads, landforms change, local soil pollution caused by fuels, cleaning agents and materials used to prepare drilling fluids, rubble, cement, gravel, pollution of surface and underground water as a result of emergency discharges of sewage, infiltration of pollution from waste reservoirs, disturbance of hydrogeological equilibrium through significant water intake, noise and atmospheric pollution resulted from the combustion of fuels.

    The analysis of environmental risk should be an integral part of risk analysis in a company, which should be carried out in a systematic manner, based on the most up-to-date information and the best available techniques, and it should constantly be improved (Baisch and Pater, 2011). The best solution is to use a combination of the qualitative method (based on good practices and experience) and the quantitative method, determining the value of the effect and the probability of occurrence of a given risk. The results obtained by such assessment are objective and comparable.

  • In the present paper, the method has been demonstrated for three shale gas wells marked as S-1, S-2 and S-3 and three tight gas wells: T-1, T-2, T-3 (Fig. 1).

    Figure 1.  Estimated shale gas basins in Poland with shale gas wells S-1, S-2, S-3 and tight gas wells T-1, T-2, T-3 (United States, Energy Information Administration, World Tight Oil and Shale Gas Resource Assessment, 2013).

    Polish reserves of both conventional and unconventional oil and gas concentrate in four regions: the Carpathians, Carpathian Foredeep, Polish Lowlands and the Baltic Sea. The largest resources and reservoirs of hydrocarbons occur in the Polish Lowlands. Shale gas may occur in Upper Ordovician and Lower Silurian shales in the Polish economic zone of the Baltic Sea, in Pomerania, East and North Mazowsze, Podlasie and in the Lublin region. It may also be present in Lower Carboniferous shales of the Fore-Sudetic region. Tight gas reservoirs are expected to occur in Central Poland (mainly in the Poznań-Kalisz zone) in Rotliegend (Lower Permian) and Carboniferous rocks, as well as in Middle Cambrian rocks in North Poland.

    Unconventional accumulations of natural gas in Poland are mainly contained in black Silurian and Ordovician clay shales, and Rotliegend sandstones. Shale gas and tight gas reservoirs have been formed in the central part of sedimentary basin.

    They do not occur in reservoir traps nor are underlain by the water. That is why horizontal drilling and hydraulic fracturing are required in order to produce natural gas from such reservoirs.

    Shale gas wells S-1, S-2 and S-3 are located at Pomeranian region of Poland. They are in the sediments of the older Paleozoic: Cambrian, Ordovician and Silurian. Their depth varies from 3 980 to 5 058 m as it shown at Figs. S1-S3.

    Tight gas wells T-1, T-2, T-3 are located in Carpathian region of Poland. They are found mainly in Neogene formations, and their depth varies from 1 573 to 2 882 m (Figs. S4-S6).

    The proposed method of conducting the risk analysis includes a list of key environmental threats that can occur at the stage of exploration, production and decommissioning.

    First, particular threats were classified according to the localization (L1-L8) and environmental (E1-E8) criteria.

    L(1) Nature protection: location directly in Natura 2 000 areas, National Parks with buffer zone, Reserves with buffer zone, Landscape Parks with buffer zone;

    L(2) Close nature protection: location less than 500 m from nature protection zones;

    L(3) Landslides and wetlands: location in the immediate proximity of landslides, or wetlands;

    L(4) Water protection: in groundwater intakes protection areas and inland water reservoirs;

    L(5) Floods zone: location in areas threatened by floods;

    L(6) SPA protection: location near the spa protection zone, high concentration of summer housing, in a zone less than 500 m from residential buildings;

    L(7) Plants: near plants or other dangerous installations;

    L(8) Archeological sites: location near archeological sites;

    E(1) Spills: spills of fuels, chemical substances and mixtures as well as liquid waste into the environment;

    E(2) Water intake: increased intake of surface and underground waters;

    E(3) ENERGY intake: increased energy intake;

    E(4) Wastewater: increased wastewater production;

    E(5) Waste: increased production of dangerous and other dangerous waste;

    E(6) Radioactivity: increased radioactivity;

    E(7) Agricultural destruction: destruction of agricultural and forestry crops, disturbance of protected species;

    E(8) Noise: oversized noise;

    E(9) Lighting: use of lighting at night;

    E(10) Traffic: increased traffic;

    E(11) Vibrations: vibrations, induced seismic shocks;

    E(12) Air emissions: emissions of gases and dust to air;

    E(13) Water regime: changes in water regime;

    E(14) Land destruction: destruction/disturbance of reclamation, roads, bridges, land deformation, launch of landslides, violation of wetlands continuity.

    Based on the data collected for each shale gas and tight gas well, the likelihood probability P of a possible event in the past was analyzed.

    P=1, if the event occurred a maximum of once a year; P=2, if the event occurred more than once a year; P=3, if the event occurred repeatedly throughout the year.

    The effects s determine the possible impact on the environment and the human being.

    s=0, no influence;

    s=1, little impact on the environment and human being, e.g., increased emission of air pollutants, amount of waste production, consumption of surface and underground water, noise emission in relation to the initial state before the investment;

    s=2, significant impact on the environment and human beings, e.g., exceeded permissible of air pollutant emission limits, waste production, noise and water intake, spills, land and agricultural deformations;

    s=3, large impact on the environment and human beings, e.g., accidents with irreversible consequences for the environment and people's lives.

    Location (L1-L8) and environmental (E1-E8) threats for each impact as well as the projected probability based on the registered past events was determined individually for six wells, labelled three shale gas wells S1-S3 and three tight gas wells T1-T3. Details are given in Annex 1 and Annex 2.

    Type of threats Exploration Production Decomissioning
    P s P s P s
    L(1) Nature protection 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(2) Close nature protection 0, 7 0, 7 1, 7 1, 0 2, 0 1, 0
    L(3) Landslides and wetlands 0, 3 0, 3 1, 0 0, 7 0, 3 0, 3
    L(4) Water protection 0, 7 0, 7 2, 0 0, 7 0, 7 0, 7
    L(5) Floods zone 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(6) Spa protection 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(7) Plants 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(8) Archeological sites 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    E(1) Spills 0, 0 0, 0 2, 3 1, 0 1, 3 1, 0
    E(2) Water intake 0, 0 0, 0 2, 3 1, 0 0, 0 0, 0
    E(3) Energy intake 0, 0 0, 0 2, 0 1, 0 0, 0 0, 0
    E(4) Wastewater 0, 0 0, 0 3, 0 1, 0 2, 0 1, 0
    E(5) Waste 0, 0 0, 0 2, 0 2, 0 2, 0 2, 0
    E(6) Radioactivity 0, 0 0, 0 1, 0 1, 0 0, 0 0, 0
    E(7) Agricultural destruction 1, 3 1, 0 3, 0 1, 0 0, 7 0, 7
    E(8) Noise 1, 0 1, 0 2, 0 1, 0 1, 0 1, 0
    E(9) Lighting 0, 0 0, 0 1, 7 1, 0 0, 0 0, 0
    E(10) Traffic 2, 0 1, 0 3, 0 1, 0 1, 0 1, 0
    E(11) Vibrations 2, 0 1, 0 2, 0 1, 0 0, 0 0, 0
    E(12) Air emissions 1, 0 1, 0 2, 0 1, 0 1, 0 1, 0
    E(13) Water regime 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    E(14) Land destruction 2, 7 1, 0 2, 7 1, 0 0, 7 0, 7

    Table 1.  Matrix of impacts and probabilities on shale gas wells

    Type of threats Exploration Production Decomissioning
    P s P s P s
    L(1) Nature protection 0, 3 0, 3 0, 3 0, 3 0, 3 0, 3
    L(2) Close nature protection 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(3) Landslides and wetlands 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(4) Water protection 0, 3 0, 3 1, 3 1, 3 0, 7 1, 0
    L(5) Floods zone 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(6) Spa protection 0, 7 0, 7 0, 7 0, 7 0, 7 0, 7
    L(7) Plants 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    L(8) Archeological sites 0, 0 0, 0 0, 0 0, 0 0, 0 0, 0
    E(1) Spills 0, 0 0, 0 2, 0 1, 0 1, 0 1, 0
    E(2) Water intake 0, 0 0, 0 3, 0 1, 0 0, 0 0, 0
    E(3) Energy intake 0, 0 0, 0 2, 0 1, 0 0, 0 0, 0
    E(4) Wastewater 0, 0 0, 0 2, 0 1, 0 2, 0 1, 0
    E(5) Waste 0, 0 0, 0 3, 0 1, 0 3, 0 1, 0
    E(6) Radioactivity 0, 0 0, 0 1, 0 1, 0 0, 0 0, 0
    E(7) Agricultural destruction 1, 0 1, 0 3, 0 1, 0 0, 0 0, 0
    E(8) Noise 1, 0 1, 0 3, 0 1, 0 1, 0 1, 0
    E(9) Lighting 0, 0 0, 0 2, 0 1, 0 0, 0 0, 0
    E(10) Traffic 1, 0 1, 0 3, 0 1, 0 1, 0 1, 0
    E(11) Vibrations 1, 0 1, 0 2, 0 2, 0 0, 0 0, 0
    E(12) Air emissions 1, 0 1, 0 2, 0 1, 0 0, 0 0, 0
    E(13) Water regime 0, 0 0, 0 2, 0 2, 0 0, 0 0, 0
    E(14) Land destruction 1, 0 1, 0 3, 0 1, 0 0, 0 0, 0

    Table 2.  Matrix of impacts and probabilities on tight gas wells

    Then, with the risk matrix (Table 1), the risk level of a given event is determined. The risk (R) is the product of the probability of occurrence of the analyzed event (P) and the scale of its negative effects on the environment and human beings (s).

    Probability of an event occurring
    Environmental and human impact Once a year or not at all More than once a year Many times a year
    1 Little 2 Average 3 Big
    Little impact on the environment and human 1 Little 1 Low risk 2 Low risk 3 Medium risk
    Significant impact on the environment and human 2 Average 2 Low risk 4 Medium risk 6 High risk
    Big impact on the environment and human 3 Big 3 Medium risk 6 High risk 9 High risk

    Table 1.  Risk matrix (own elaboration)

    According to Table 1, it is assumed that a high risk (4.5 < R < 9) occurs if the analyzed event may occur many times a year or in the near future and it would cause a large impact on the environment and human beings. An average risk (2.5 < R < 4.5) occurs if the analyzed event may occur one or more times a year and it would cause a significant impact on the environment and human beings. A low risk (0.5 < R < 2.5), treated as negligible, occurs if the analyzed event may occur once a year or not at all and it

    Due to the changing local, environmental and social conditions, a separate environmental risk assessment is required for each work location. Ultimately, for each risk case, minimizing measures and proposed risk management methods should be defined.

    Next, the average risk factors ${{{\bar{r}}}^{j}}$ related to the threat of type j have been determined as follows.

    The average risk level ${{{\bar{r}}}^{j}}$ was determined separately for all three shale gas wells (i=1…3), all tight gas wells (i=4…6) as well as for all six wells (i=1…6). Results are shown in Table 2.

  • As we can see in the Section 3 due to the low permeability of shale gas and tight gas rocks, hydraulic fracturing is used in the production, which is usually accompanied by high water consumption, large amounts of sewage, seismic activity and greenhouse gas emissions. The noise caused by the work and the more heavy traffic of trucks, agricultural and land destruction are further reasons for concern for the environment and society. In addition, flow-back water may also contain various components absorbed during contact with rocks, including naturally occurring radioactive substances. Also spills of fuels, chemical substances and mixtures as well as liquid waste into the environment are possible.

    First of all, it should be noted that the impact of works related to the exploration and subsequent exploitation of unconventional hydrocarbons on people and the environment, is only short-term and transitory. As shown in Annex 1 and Annex 2, the environmental impact and probabilities of each threat during the shale gas and tight gas exploration phase is very low. The highest impact and probabilities can be identified at the production phase. Generally the most common threats comprise agricultural and land destruction, increased energy consumption, spills and traffic. The impacts at the decommissioning phase comprise emissions of wastewater and waste, and are generally lower than during the exploration and production.

    As shown in Table 2, the total risk during the exploration phase, determined on three shale gas (S-1, S-2, S-3) and three tight gas (T-1, T-2, T-3) testing sites is low and does not exceed the value of R < 2. Small deformations of access roads and destruction of arable fields are visible. An increased risk value (2 < R≤4.16) takes place during the exploitation phase. However, this is still a medium-scale risk and it is associated with increased water intake, sewage and waste production. Traffic, vibrations and the emission of noise generated are also relevant. The completion of works phase is characterized by a temporary interference with the environment and it comprises actions related to bringing the environment to the best possible state. The risk of individual threats at this stage has been identified as low. The average risk level only occurs in the case of a final large amount of waste. It should be emphasized that in none of the analyzed cases the risk level exceeded the value of R≤4.5 and therefore it was not classified as a high risk. Also, the environmental threats generate more risky situations than the location threats.

    Due to the few regions of occurrence shale gas S-1, S-2, S-3 and tight gas wells T-1, T-2, T-3 can be representative in the field of environmental risk assessment for Pomeranian and Carpathian region of Poland. But the study should be carried out using the same methodology as presented in Section 3 for other regions of Poland where we can find unconventional hydrocarbons.

  • The presented model of environmental risk analysis allows the identification of key risk factors affecting the implementation of works related to the exploration and exploitation of unconventional hydrocarbons in Polish conditions. The result of this identification is a risk register. The largest environmental risks identified at the S-1 and T-3 wells are related to the location in wetlands and with an increased intake of surface and underground waters. This is a major threat causing the reduction of groundwater at the stage of investment and it requires a continuous monitoring. In the case of other identified threats, medium-level risks requiring monitoring and small ones requiring only a periodic verification without monitoring were noted.

    Recommendations for future actions comprise developing schemes for dealing with risk by undertaking mitigation activities. When planning investments related to the operation of unconventional hydrocarbons, corporate specialists of environmental protection services use spatial data from a map system (e.g., Geoserwis) concerning, among others, forms of nature conservation in Poland conducted by the General Director for Environmental Protection. The combination of information contained in the risk analysis sheet (Table 2) with Arc Gis intended for work on GIS (Spatial Information Systems) data through a dedicated application can be a comprehensive tool supporting the work in the field of risk management. After marking a given location on the map, the investor would receive a quick feedback on the potential environmental risks. Such a solution would give the opportunity to professionally support decisions regarding the exploitation of unconventional hydrocarbons. Because the environmental risk is dynamic, the risk assessors are obliged to monitor it continuously and take into account the results of this monitoring in the risk management strategy.

Reference (23)
Supplements:
jes-31-1-215-FigureS6.pdf
jes-31-1-215-FigureS1.pdf
jes-31-1-215-FigureS3.pdf
jes-31-1-215-FigureS4.pdf
jes-31-1-215-FigureS2.pdf
jes-31-1-215-FigureS5.pdf

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