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Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe European Commission DG Environment AEA/R/ED57281 Issue Number 11 17 Date 10/08/2012 28/05/2012 Report for Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe Customer: Contact: European Commission DG Environment Dr Mark Broomfield AEA Technology plc Gemini Building, Harwell, Didcot, OX11 0QR t: 0870 190 6389 e: mark.broomfield@aeat.co.uk AEA is a business name of AEA Technology plc AEA is certificated to ISO9001 and ISO14001 Customer reference: 07.0307/ENV.C.1/2011/604781/ENV.F1 Confidentiality, copyright & reproduction: This report is the Copyright of the European Commission DG Environment and has been prepared by AEA Technology plc under contract to the European Commission DG Environment ref 07.0307/ENV.C.1/2011/604781/ENV.F1. The contents of this report may not be reproduced in whole or in part, nor passed to any organisation or person without the specific prior written permission of the European Commission DG Environment. AEA Technology plc accepts no liability whatsoever to any third party for any loss or damage arising from any interpretation or use of the information contained in this report, or reliance on any views expressed therein. This document does not represent the views of the European Commission. The interpretations and opinions contained in it are solely those of the authors. Author: Dr Mark Broomfield Approved By: Andrew Lelland Date: 10 August 2012 Signed: AEA reference: Ref: ED57281- Issue Number 17 Ref: AEA/ED57281/Issue Number 17 ii Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe Executive summary Introduction Exploration and production of natural gas and oil within Europe has in the past been mainly focused on conventional resources that are readily available and relatively easy to develop. This type of fuel is typically found in sandstone, siltstone and limestone reservoirs. Conventional extraction enables oil or gas to flow readily into boreholes. As opportunities for this type of domestic extraction are becoming increasingly limited to meet demand, EU countries are now turning to exploring unconventional natural gas resources, such as coalbed methane, tight gas and in particular shale gas. These are termed ‘unconventional’ resources because the porosity, permeability, fluid trapping mechanism, or other characteristics of the reservoir or rock formation from which the gas is extracted differ greatly from conventional sandstone and carbonate reservoirs. In order to extract these unconventional gases, the characteristics of the reservoir need to be altered using techniques such as hydraulic fracturing. In particular high volume hydraulic fracturing has not been used to any great extent within Europe for hydrocarbon extraction. Its use has been limited to lower volume fracturing of some tight gas and conventional reservoirs in the southern part of the North Sea and in onshore Germany, the Netherlands, Denmark and the UK. Preliminary indications are that extensive shale gas resources are present in Europe (although this would need to be confirmed by exploratory drilling). To date, it appears that only Poland and the UK have performed high-volume hydraulic fracturing for shale gas extraction (at one well in the UK and six wells in Poland); however, a considerable number of Member States have expressed interest in developing shale gas resources. Those already active in this area include Poland, Germany, the Netherlands, the UK, Spain, Romania, Lithuania, Denmark, Sweden and Hungary. The North American context Technological advancements and the integration of horizontal wells with hydraulic fracturing practices have enabled the rapid development of shale gas resources in the United States – at present the only country globally with significant commercial shale gas extraction. There, rapid developments have also given rise to widespread public concern about improper operational practices and health and environmental risks related to deployed practices. A 2011 report from the US Secretary of Energy Advisory Board (SEAB) put forward a set of recommendations aiming at "reducing the environmental impact "and "helping to ensure the safety of shale gas production." Almost half of all states have recently enacted, or have pending legislation that regulates hydraulic fracturing. In 2012, the US Environmental Protection Agency (EPA) has issued Final Oil and Natural Gas Air Pollution Standards including for natural gas wells that are hydraulically fractured as well as Draft Permitting Guidance for Oil and Gas Hydraulic Fracturing Activities Using Diesel Fuels. The EPA is also developing standards for waste water discharges and is updating chloride water quality criteria, with a draft document expected in 2012. In addition, it is implementing an Energy Extraction Enforcement Initiative, and is involved in voluntary partnerships, such as the Natural Gas STAR program. The US Department of the Interior proposed in April 2012 a rule to require companies to publicly disclose the chemicals used in hydraulic fracturing operations, to make sure that wells used in fracturing operations meet appropriate construction standards, and to ensure that operators put in place appropriate plans for managing flowback waters from fracturing operations). Ref: AEA/ED57281/Issue Number 17 iii Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe The general European context In February 2011, the European Council concluded that Europe should assess its potential for sustainable extraction and use of both conventional and unconventional fossil fuel resources.1 A 2011 report commissioned by the European Parliament drew attention to the potential health and environmental risks associated with shale gas extraction. At present, close to half of all EU Member States are interested in developing shale gas resources, if possible. Member States active in this area include Poland, Germany, Netherlands, UK, Spain, Romania, Lithuania and Denmark. Sweden, Hungary and other EU Member States may also be interested in developing activity in this area. However, in response to concerns raised by the general public and stakeholders, several European Member States have prohibited, or are considering the possibility to prohibit the use of hydraulic fracturing. Concurrently, several EU Member States are about to initiate discussions on the appropriateness of their national legislation, and contemplate the possibility to introduce specific national requirements for hydraulic fracturing. The recent evolution of the European context suggests a growing need for a clear, predictable and coherent approach to unconventional fossil fuels and in particular shale gas developments to allow optimal decisions to be made in an area where economics, finances, environment and in particular public trust are essential. Against this background, the Commission is investigating the impact of unconventional gas, primarily shale gas, on EU energy markets and has requested this initial, specific assessment of the environmental and health risks and impacts associated with the use of hydraulic fracturing, in particular for shale gas. Study focus and scope This report sets out the key environmental and health risk issues associated with the potential development and growth of high volume hydraulic fracturing in Europe. The study focused on the net incremental impacts and risks that could result from the possible growth in use of these techniques. This addresses the impacts and risks over and above those already addressed in regulation of conventional gas exploration and extraction. The study distinguishes shale gas associated practices and activities from conventional ones that already take place in Europe, and identifies the potential environmental issues which have not previously been encountered, or which could be expected to present more significant challenges. The study reviewed available information on a range of potential risks and impacts of high volume hydraulic fracturing. The study concentrated on the direct impacts of hydraulic fracturing and associated activities such as transportation and wastewater management. The study did not address secondary or indirect impacts such as those associated with materials extraction (stone, gravel etc.) and energy use related to road, infrastructure and well pad construction. The study has drawn mainly on experience from North America, where hydraulic fracturing has been increasingly widely practised since early in the 2000s. The views of regulators, geological surveys and academics in Europe and North America were sought. Where possible, the results have been set in the European regulatory and technical context. The study includes a review of the efficiency and effectiveness of current EU legislation relating to shale gas exploration and production and the degree to which the current EU framework adequately covers the impacts and risks identified. It also includes a review of risk management measures. 1 European Council, Conclusions on Energy, 4 February 2011 (http://www.consilium.europa.eu/uedocs/cms_Data/docs/pressdata/en/ec/119141.pdf) Ref: AEA/ED57281/Issue Number 17 iv Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe Preliminary risk assessment The main risks were assessed at each stage of a project (well-pad) development, and also covered the cumulative environmental effects of multiple installations. The stages are: 1. Well pad site identification and preparation 2. Well design, drilling, casing and cementing 3. Technical hydraulic fracturing stage 4. Well completion 5. Well production 6. Well abandonment. The study adopted a risk prioritisation approach to enable objective evaluation. The magnitude of potential hazards and the expected frequency or probability of the hazards were categorised on the basis of expert judgement and from analysis of hydraulic fracturing in the field where this evidence was available to allow risks to be evaluated. Where the uncertainty associated with the lack of information about environmental risks was significant, this has been duly acknowledged. This approach enabled a prioritisation of overall risks. The study authors duly acknowledge the limits of this risk screening exercise, considering notably the absence of systematic baseline monitoring in the US (from where most of the literature sources come), the lack of comprehensive and centralised data on well failure and incident rates, and the need for further research on a number of possible effects including long term ones. Because of the inherent uncertainty associated with environmental risk assessment studies, expert judgement was used to characterise these effects. The study identified a number of issues as presenting a high risk for people and the environment. These issues and their significance are summarised in the following table. Ref: AEA/ED57281/Issue Number 17 v Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe Table ES1: Summary of preliminary risk assessment Project phase Site Environmental identification aspect and preparation Well Well design Overall Well abandonment drilling, Fracturing Production rating across completion and postcasing, all phases abandonment cementing Individual site Groundwater contamination Not applicable Low ModerateHigh High ModerateHigh Not classifiable High Surface water contamination Low Moderate ModerateHigh High Low Not applicable High Not applicable Not applicable Moderate Not applicable Moderate Not applicable Moderate Low Moderate Moderate Moderate Moderate Low Moderate Moderate Not applicable Not applicable Not applicable Moderate Not classifiable Moderate Not classifiable Low Low Low Moderate Not classifiable Moderate Noise impacts Low Moderate Moderate Not classifiable Low Not applicable Moderate – High Visual impact Low Low Low Not applicable Low Low-moderate Low Moderate Not applicable Not applicable Low Low Not applicable Not applicable Low Low Low Moderate Low Low Not applicable Moderate Water resources Release to air Land take Risk to biodiversity Seismicity Traffic Cumulative Groundwater contamination Not applicable Low ModerateHigh High High Not classifiable High Surface water contamination Moderate Moderate ModerateHigh High Moderate Not applicable High Water resources Not applicable Not applicable High Not applicable High Not applicable High Low High High High High Low High Land take Very high Not applicable Not applicable Not applicable High Not classifiable High Risk to biodiversity Not classifiable Low Moderate Moderate High Not classifiable High Noise impacts Low High Moderate Not classifiable Low Not applicable High Visual impact Moderate Moderate Moderate Not applicable Low Low-moderate Moderate Seismicity Not applicable Not applicable Low Low Not applicable Not applicable Low High High High Moderate Low Not applicable High Release to air Traffic Not applicable: Impact not relevant to this stage of development Not classifiable: Insufficient information available for the significance of this impact to be assessed Ref: AEA/ED57281/Issue Number 17 vi Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe General risk causes In general, the main causes of risks and impacts from high-volume hydraulic fracturing identified in the course of this study are as follows: • • • • • The use of more significant volumes of water and chemicals compared to conventional gas extraction The lower yield of unconventional gas wells compared to conventional gas wells means that the impacts of HVHF processes can be greater than the impacts of conventional gas exploration and production processes per unit of gas extracted. The challenge of ensuring the integrity of wells and other equipment throughout the development, operational and post-abandonment lifetime of the plant (well pad) so as to avoid the risk of surface and/or groundwater contamination The challenge of ensuring that spillages of chemicals and waste waters with potential environmental consequences are avoided during the development and operational lifetime of the plant (well pad) The challenge of ensuring a correct identification and selection of geological sites, based on a risk assessment of specific geological features and of potential uncertainties associated with the long-term presence of hydraulic fracturing fluid in the underground The potential toxicity of chemical additives and the challenge to develop greener alternatives • The unavoidable requirement for transportation of equipment, materials and wastes to and from the site, resulting in traffic impacts that can be mitigated but not entirely avoided. • The potential for development over a wider area than is typical of conventional gas fields • The unavoidable requirement for use of plant and equipment during well construction and hydraulic fracturing, leading to emissions to air and noise impacts. Environmental pressures • Land-take The American experience shows there is a significant risk of impacts due to the amount of land used in shale gas extraction. The land use requirement is greatest during the actual hydraulic fracturing stage (i.e. stage 3), and lower during the production stage (stage 5). Surface installations require an area of approximately 3.6 hectares per pad for high volume hydraulic fracturing during the fracturing and completion phases, compared to 1.9 hectares per pad for conventional drilling. Land-take by shale gas developments would be higher if the comparison is made per unit of energy extracted. Although this cannot be quantified, it is estimated that approximately 50 shale gas wells might be needed to give a similar gas yield as one North Sea gas well. Additional land is also required during re-fracturing operations (each well can typically be re-fractured up to four times during a 40 years well lifetime). Consequently, approximately 1.4% of the land above a productive shale gas well may need to be used to exploit the reservoir fully. This compares to 4% of land in Europe currently occupied by uses such as housing, industry and transportation. This is considered to be of potentially major significance for shale gas development over a wide area and/or in the case of densely populated European regions. The evidence suggests that it may not be possible fully to restore sites in sensitive areas following well completion or abandonment, particularly in areas of high agricultural, natural or cultural value. Over a wider area, with multiple installations, this could result in a significant loss or fragmentation of amenities or recreational facilities, valuable farmland or natural habitats. Ref: AEA/ED57281/Issue Number 17 vii Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe Releases to air Emissions from numerous well developments in a local area or wider region could have a potentially significant effect on air quality. Emissions from wide scale development of a shale gas reservoir could have a significant effect on ozone levels. Exposure to ozone could have an adverse effect on respiratory health and this is considered to be a risk of potentially high significance. The technical hydraulic fracturing stage also raises concerns about potential air quality effects. These typically include diesel fumes from fracturing liquid pumps and emissions of hazardous pollutants, ozone precursors and odours due to gas leakage during completion (e.g. from pumps, valves, pressure relief valves, flanges, agitators, and compressors). There is also concern about the risk posed by emissions of hazardous pollutants from gases and hydraulic fracturing fluids dissolved in waste water during well completion or recompletion. Fugitive emissions of methane (which is linked to the formation of photochemical ozone as well as climate impacts) and potentially hazardous trace gases may take place during routeing gas via small diameter pipelines to the main pipeline or gas treatment plant. On-going fugitive losses of methane and other trace hydrocarbons are also likely to occur during the production phase. These may contribute to local and regional air pollution with the potential for adverse impacts on health. With multiple installations the risk could potentially be high, especially if re-fracturing operations are carried out. Well or site abandonment may also have some impacts on air quality if the well is inadequately sealed, therefore allowing fugitive emissions of pollutants. This could be the case in older wells, but the risk is considered low in those appropriately designed and constructed. Little evidence exists of the risks posed by movements of airborne pollutants to the surface in the long-term, but experience in dealing with these can be drawn from the management of conventional wells. Noise pollution Noise from excavation, earth moving, plant and vehicle transport during site preparation has a potential impact on both residents and local wildlife, particularly in sensitive areas. The site preparation phase would typically last up to four weeks but is not considered to differ greatly in nature from other comparable large-scale construction activity. Noise levels vary during the different stages in the preparation and production cycle. Well drilling and the hydraulic fracturing process itself are the most significant sources of noise. Flaring of gas can also be noisy. For an individual well the time span of the drilling phase will be quite short (around four weeks in duration) but will be continuous 24 hours a day. The effect of noise on local residents and wildlife will be significantly higher where multiple wells are drilled in a single pad, which typically lasts over a five-month period. Noise during hydraulic fracturing also has the potential to temporarily disrupt and disturb local residents and wildlife. Effective noise abatement measures will reduce the impact in most cases, although the risk is considered moderate in locations where proximity to residential areas or wildlife habitats is a consideration. It is estimated that each well-pad (assuming 10 wells per pad) would require 800 to 2,500 days of noisy activity during pre-production, covering ground works and road construction as well as the hydraulic fracturing process. These noise levels would need to be carefully controlled to avoid risks to health for members of the public. Surface and groundwater contamination The study found that there is a high risk of surface and groundwater contamination at various stages of the well-pad construction, hydraulic fracturing and gas production processes, and during well abandonment. Cumulative developments could further increase this risk. Ref: AEA/ED57281/Issue Number 17 viii Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe Runoff and erosion during early site construction, particularly from storm water, may lead to silt accumulation in surface waters and contaminants entering water bodies, streams and groundwater. This is a problem common to all large-scale mining and extraction activities. However, unconventional gas extraction carries a higher risk because it requires high-volume processes per installation and the risks increase with multiple installations. Shale gas installations are likely to generate greater storm water runoff, which could affect natural habitats through stream erosion, sediment build-up, water degradation and flooding. Mitigation measures, such as managed drainage and controls on certain contaminants, are well understood. Therefore the hazard is considered minor for individual installations with a low risk ranking and moderate hazard for cumulative effects with a moderate risk ranking. Road accidents involving vehicles carrying hazardous materials could also result in impacts on surface water. The study considered the water contamination risks of sequential as well as simultaneous (i) well-drilling and (ii) hydraulic fracturing. i. ii. Poor well design or construction can lead to subsurface groundwater contamination arising from aquifer penetration by the well, the flow of fluids into, or from rock formations, or the migration of combustible natural gas to water supplies. In a properly constructed well, where there is a large distance between drinking water sources and the gas producing zone and geological conditions are adequate, the risks are considered low for both single and multiple installations. Natural gas well drilling operations use compressed air or muds as the drilling fluid. During the drilling stage, contamination can arise as a result of a failure to maintain storm water controls, ineffective site management, inadequate surface and subsurface containment, poor casing construction, well blowout or component failure. If engineering controls are insufficient, the risk of accidental release increases with multiple shale gas wells. Cuttings produced from wells also need to be properly handled to avoid for instance the risk of radioactive contamination. Exposure to these could pose a small risk to health, but the study concluded that this would only happen in the event of a major failure of established control systems. No evidence was found that spillage of drilling muds could have a significant effect on surface waters. However, in view of the potential significance of spillages on sensitive water resources, the risks for surface waters were considered to be of moderate significance. The risks of surface water and groundwater contamination during the technical hydraulic fracturing stage are considered moderate to high. The likelihood of properly injected fracturing liquid reaching underground sources of drinking water through fractures is remote where there is more than 600 metres separation between the drinking water sources and the producing zone. However, the potential of natural and manmade geological features to increase hydraulic connectivity between deep strata and more shallow formations and to constitute a risk of migration or seepage needs to be duly considered. Where there is no such large depth separation, the risks are greater. If wastewater is used to make up fracturing fluid, this would reduce the water requirement, but increase the risk of introducing naturally occurring chemical contaminants and radioactive materials into aquifers in the event of well failure or of fractures extending out of the production zone. The potential wearing effects of repeated fracturing on well construction components such as casings and cement are not sufficiently understood and more research is needed. In the production phase, there are a number of potential effects on groundwater associated however with the inadequate design or failure of well casing, leading to potential aquifer contamination. Substances of potential concern include naturally occurring heavy metals, natural gas, naturally occurring radioactive material and technologically enhanced radioactive material from drilling operations. The risks to groundwater are considered to be moderatehigh for individual sites, and high for development of multiple sites. Ref: AEA/ED57281/Issue Number 17 ix Support to the identification of potential risks for the environment and human health arising from hydrocarbons operations involving hydraulic fracturing in Europe Inadequate sealing of a well after abandonment could potentially lead to both groundwater and surface water contamination, although there is currently insufficient information available on the risks posed by the movement of hydraulic fracturing fluid to the surface over the long term to allow these risks to be characterised. The presence of high-salinity fluids in shale gas formations indicates that there is usually no pathway for release of fluids to other formations under the geological conditions typically prevailing in these formations, although recently published research indicates that pathways may potentially exist in certain geological areas such as those encountered in parts of Pennsylvania, emphasising the need for a high standard of characterisation of these conditions. Water resources The hydraulic fracturing process is water-intensive and therefore the risk of significant effects due to water abstraction could be high where there are multiple installations. A proportion of the water used is not recovered. If water usage is excessive, this can result in a decrease in the availability of public water supply; adverse effects on aquatic habitats and ecosystems from water degradation, reduced water quantity and quality; changes to water temperature; and erosion. Areas already experiencing water scarcity may be affected especially if the longer term climate change impacts of water supply and demand are taken into account. Reduced water levels may also lead to chemical changes in the water aquifer resulting in bacterial growth causing taste and odour problems with drinking water. The underlying geology may also become destabilised due to upwelling of lower quality water or other substances. Water withdrawal licences for hydraulic fracturing have recently been suspended in some areas of the United States. Biodiversity impacts Unconventional gas extraction can affect biodiversity in a number of ways. It may result in the degradation or complete removal of a natural habitat through excessive water abstraction, or the splitting up of a habitat as a result of road construction or fencing being erected, or for the construction of the well-pad itself. New, invasive species such as plants, animals or micro-organisms may be introduced during the development and operation of the well, affecting both land and water ecosystems. This is an area of plausible concern but there is as yet no clear evidence base to enable the significance to be assessed. Well drilling could potentially affect biodiversity through noise, vehicle movements and site operations. The treatment and disposal of well drilling fluids also need to be adequately handled to avoid damaging natural habitats. However, these risks are lower than during other stages of shale drilling. During hydraulic fracturing, the impacts on ecosystems and wildlife will depend on the location of the well-pad and its proximity to endangered or threatened species. Sediment runoff into streams, reductions in stream flow, contamination through accidental spills and inadequate treatment of recovered waste-waters are all seen as realistic threats as is water depletion. However, the study found that the occurrence of such effects was rare and cumulatively the risks could be classified as moderate. Effects on natural ecosystems during the gas production phase may arise due to human activity, traffic, land-take, habitat degradation and fragmentation, and the introduction of invasive species. Pipeline construction could affect sensitive ecosystems and re-fracturing would also cause continuing impacts on biodiversity. The possibility of land not being suitable for return to its former use after well abandonment is another factor potentially affecting local ecosystems. Biodiversity risks during the production phase were considered to be potentially high for multiple installations. Traffic Total truck movements during the construction and development phases of a well are estimated at between 7,000 and 11,000 for a single ten-well pad. These movements are temporary in duration but would adversely affect both local and national roads and may have Ref: AEA/ED57281/Issue Number 17 x