Photo: Circle of blue.org
Researchers at the Tyndall Centre at Manchester University, England, investigated the impacts of shale gas on the environment and climate change. The exploitation of shale gas, or shale, is launched in the U.S. and will begin soon in Britain. Here
the 10th part of a loose translation of the preliminary report from the Tyndall Centre for Climate Change Research. The original is here: http://www.tyndall.ac.uk/shalegasreport with a link to download the report in pdf format of 87 pages. The
As the report is: 
groundwater contaminant migration paths exposure detailed above may be supplemented with other ways, eg via fractures caused by man or nature, and eventually contaminate groundwater or surface. Documents GWPC provides data on depths and water courses which could be processed and determined that apart New Albany and Antrim wells should be drilled to depths of over 3,000 feet (900 meters) below the soil surface. Because of this, some comments tend to dismiss out of hand the potential for water contamination because the target formations are often well below the aquifers and that contaminants would migrate through the rock which separates them.
For example, reports the New York State (2009) states that the purpose of hydraulic fracturing is limited to fractures in the geological formation targeted because excessive vertical fracturing is not desirable due to costs incurred . Expenses related to the time and superfluous materials are mentioned, as well as additional costs of handling waste water and / or economic loss of oil if ever the surrounding rock formations contain water that seeps into the training tank (of gas). Although this might be true, it does not negate the possibility that the fractures may extend vertically beyond the target formation and thus prolong or add passages between previously isolated formations. For example, the document New York State (2009) cites a report that cites ICF despite laboratory experiments and field still running, the mechanisms that limit the growth of vertical fractures are not fully known. Incidents like those mentioned above serve to demonstrate that together, the following exposure routes can (and do) act in tandem to cause contamination of groundwater as well:
- from the outside of the hole Drilling itself;
- other holes (like those who have not been completed, poorly constructed or older wells or improperly sealed;
- by fractures made during the process of Hydraulic fracturing;
- by natural fissures, cracks and pores interconnected.
Figure 4.1 compares the relative depths of the formations and groundwater.
4.2.4 Exposure Pathways - surface water and soil contamination
routes of exposure on the surface and surface water by groundwater are very simple.
operations conducted at individual sites of the wells require transporting materials to the site, the use of these substances, generate waste, must store these wastes and then generates the transportation of waste. For a single drill site, they boil down to this:
- clippings drilling (well cuttings) and drilling muds. A single well drilled vertically to a depth of 2 km and 1.2 km horizontally to generate approximately 140 cubic yards of shavings. Site drilling 6 wells will generate about 830 cubic meters of drill cuttings. These are usually stored in pits before being transported off site;
- transportation and temporary storage of hydraulic fracturing additive: based on 2% of the fracturing fluids and water volumes already mentioned in this report, 180 to 580 cubic meters of chemical additives (or 180 to 580 tons depending on the density) are needed for each well. The well site drilled from 1.000 to 3.500 cubic meters of chemicals (or 1.000 to 3.500 tons depending on the density) are used. As mentioned in Section 4.2.1, the exact composition of the fracturing fluids is not disclosed, but an analysis of the chemical identities leave knowing a number of substances with hazardous properties and status of priority substance in the U.S.
- flowback fluids (sewage back): each well of a borehole site will generate between 1,300 and 23.000 cubic meters of wastewater containing flowback water, chemical and fracturing of underground contaminants mobilized during the process (including toxic organic compounds, heavy metals and radioactive materials naturally called NORM). According to document New York State (20,090, about 60% of total flowback is ejected from the wells during the first 4 days after the fracturing and can be stored in the following ways:
a) uncontrolled flow through the valve in a pit lined with a waterproof canvas;
b) pouring through a choke into a pit lined
c) pour into the tanks.
dimensions and storage pits on the site and storage tanks are probably different volumes, but, relying on volume calculated above, the total capacity would exceed the expected volumes of water flowback one of the well fracturing operation, hence between 1.30 and 23.000 meters cubes.
Document New York State (2009) cites only one report mentions that the volume operator of a typical pit is 750,000 gallons (2.900 cubic meters). Based on the depth of a pool of 3 meters, the imprint of a drilling site is approximately 1,000 square meters (0.1 hectares). It also mentions that given the vast amount of potential flowback water, storage tanks temporary duty may be installed on the site even if a pool is on site. Relying on the ability of a typical pool, it means that about 20,000 cubic meters of additional storage capacity for water flowback of fracturing operation on a single well.
In terms of total volume of wastewater from a site for flowback of 6 wells drilled, the data provide a total of 7.900 to 138.000 cubic meters of water flowback per site for one fracturing operation (including fracturing and chemical contaminants in the basement counting for 2%, or 160 to 2.700 cubic meters.
Main operational risks in those processes are on a site (but not limited to):
- spills, overflows, break water from storage ponds drill shavings or sludge because of: a lack of capacity of storage, operator errors, penetrations of storm water or flood, or due to poor quality construction or failure of the double membrane within the basin;
- spills of concentrated fracturing fluids during transfer or transaction final mixing with water is done on site because of failure of roughing in, to operator error.
- spills flowback fluids during transfer to the storage place due to failure of the pipe during operations, lack of storage capacity and overflow or operator error.
- loss of integrity of the contents of the fluid flowback because of a ruptured tank overflow basin due to operator error or lack of storage capacity, adding water from storms or flood or poor quality, faulty construction or failure of the membrane of the basin.
- spills fluid flowback during the transfer of the place of storage in tank trucks for transport, spillage caused by pipe failures or operator errors.
In addition to the many risks on the site itself detailed above, the recovery and subsequent processing and payments of hazardous wastewater generated by the drilling sites, as well as the potential need for industrial treatment plants wastewater, all contribute to increased risk of contamination. The possibility that each of these events occur varies from one risk to another, and the consequences. Viewed properties toxic fracturing fluids and flowback (or their compounds), however, any spill on the ground and surface waters would likely be problematic.
Many of these risks and pathways of exposure are well known from other industrial processes and actions can be taken to reduce the possibility that such events occur. Usually, such risks persist in industrial facilities that have invested considerably to include in their design to minimize impacts if such events occur. Instead, the activities and the hazards of drilling locations identified above are part of the construction site and thus occur over a short period of time to work site itself. Invest in permanent physical containment facilities at other standardized hazardous facilities would be unlikely.
Since the exploitation of shale gas requires the construction of several wells by drilling sites, the probability of a catastrophic event causing contamination increases proportionally. The possibility of pollution incidents associated with shale development in growth changes from "possible" at a single site to the "probable" when the number of wells drilled and sites are increasing. As might be expected, there were a number of incidents reported in the U.S. including:
- in September 2009, Dimock, PA, two spills of liquid gel occurred at a drilling site natural gas that polluted wetland and caused a fish kill. Both incidents involved a lubricant used in hydraulic fracturing and high volume totaled 30,000 liters. Spills were caused by failures of pipes.
- Monongalia County, West Virginia in September 2009, a mortality of fish along the border between West Virginia and Pennsylvania has been given to the Department of Environmental Protection West Virginia. Over 30 miles of stream were impacted by the spill from West Virginia. The DEP has received several complaints from residents who suspected that the companies dumping illegal waste oil and gas in the stream.
- in Dimock, Pa., there were 2 reports of leakage of diesel from tanks at sites of high pressure hydraulic fracturing. The first leak was caused by a faulty connection on a tank and spilled about 3,000 liters of diesel has resulted in a wetland. The second leak has spilled about 400 gallons of diesel fuel contaminating the soil.
- December 12, 2006, the DEP of Pennsylvania sent a demand letter to both companies because they accumulated offenses and continued to violate the law. Among the violations cited in the letter, it says banned from brine spills on the floor. A number of incidents like this are caused by lack of implementation or compliance with legislative controls and lack of supervision on many such sites. Also, the process is difficult and expensive.
Lack of legal framework, is a recurring problem in the U.S. and January 27, 2010, U.S. EPA announced the establishment of a hotline "Eyes on Drilling" so that citizens can report suspicious activity related to non-emergency oil and gas operations.
4.3 Consumables water
As mentioned in Sections 2.2 and 4.1, each step of a hydraulic fracturing operation uses several courses of 1.100 to 2.200 cubic meters of water, so a complete operation of fracturing several steps using a single well of 9.000 to 29.000 cubic meters of water (from 9 to 29 megalitres). For all operations fracture at a site to 6 wells (six well pad), a total of 54.000 to 174 cubic meters of water (54 to 174 megalitres) would be needed for a first hydraulic fracturing.
For this, large volumes of water must be transported and stored on site. Local conditions will dictate the water source and the operators could take water directly from surface sources or groundwater or water could be delivered by tanker or pipeline. However, drilling sites themselves are spaced in an array above the targeted geological formation, covering 3 to 4 kilometers square. Since each stage of fracturing lasts 2 to 4 days by wells, pipelines dedicated to each drill site would seem unlikely for the situation of Great Britain and transport by truck or direct debits are the means chosen by G. - B. likely to obtain water. To feed a
9bcm/année production for 20 years, it is expected that water consumption would total 27.000 to 113.000 megalitres. On an average time of 20 years would be the equivalent of an annual demand for water from 1.300 to 5.600 megalitres. Annual withdrawals of the industry (excluding electricity generation) in England and Wales would be 905.000 megalitres per year. For this, the exploitation of shale gas reserves at levels sufficient to supply gas at the equivalent of 10% gas consumption in UK increase in industrial water withdrawals in England and Wales would rise by 0.6%.
Clearly, this comparison looks at total withdrawals through England and Wales and the exploitation of shale gas is concentrated in an area much smaller. Take such large amounts of water in a sustainable manner from local sources will be difficult because of the pressures already present on Water Resources in UK For example, the current exploratory drilling done by Cuadrilla Resources at Prees Hall Fylde in the UK, is in the basin of the River Wyre (and just on the edge of the flood zone). The basin covers about 578 square kilometers and the management plan for the Environment Agency (CAMS) for the River Wyre specifies that all areas are classified as subject to too many permits, or too removed, or not having water available .
4.4 Other impacts and constraints of the exploitation of shale gas
4.4.1 Overview
In addition to very serious questions about the exploitation of shale gas, chemical pollution and water withdrawals, there are a number of impacts that may be important in Britain. Those are:
- the noise pollution;
- impacts on the landscape;
- heavy traffic and damage to roads.
Of these impacts, they will present the most significant constraints on the exploitation of shale gas in Britain, either at a local level or on a larger region.
4.4.2 Noise and visual impacts and aesthetic
Regarding noise, table 2.4 provides a summary of activities required on a drill site before the operation. Based on this, It is estimated that each drill site means there will be a total of days from 500 to noisy 1.500 days of activities disturbing. Of all these activities, drilling wells will likely source of constant noise and light because the hole is 24 hours per day. Document New York State (2009) provides that each horizontal well takes 4 to 5 weeks, 24 hours a day to complete. Composite Energy company of GB provides 60 days of drilling 24 hours a day. Relying on these data, each drill site will take 8 to 12 months drilling day and night. This could be important, even if one site would be operated, but if 1.25 to 3.5 sites per square km installed, impacts of noise on a community could be substantial and prolonged.
4.4.3 Impacts on the landscape
Regarding visual impacts, each drill site will be 1.5 to 2 hectares in area and will be fed by access roads, according to document New York State , 2009. During construction, drilling sites have storage ponds, tanks, the drilling equipment, trucks, etc. ..., making it difficult to locate facilities so as to make them harmonious with the surrounding landscape. Since
of 430 to 500 drilling sites may be required to provide 9bcm/année shale gas, it is likely that in the context of the GB, the visual impacts will be controversial. Since the opportunity to improve these levels of visual intrusion is very limited (individually or collectively), these impacts with noise and construction, could provide the most significant constraints to development in UK
4.4.4 Road traffic
In addition to impacts on the site itself, the construction of drilling sites requires a large volume of truck traffic. Table 2.5 illustrates the movement of trucks through the drill site (based on a site of 6 boreholes) to document New York State (2009). This provides a total number of visits trucks from 4.3900 to 6.600 for the construction of a single drill site. Impacts to local traffic from 1.25 to 3.5 sites per square km are clearly important, especially in a densely populated country like G.-B.
United States, the heavy traffic on roads and ensuing damage have been the source of problems. For example, it is reported that the Transport Department of West Virginia has increased the bail that industrial gas drillers must pay $ 6,000 to $ 100,000 per mile. Pennsylvania thinks establish a new settlement where the funds must be replenished to repair roads that were not designed for heavy truck traffic that comes with the industrial gas drilling.
The continuation and conclusion of the unofficial translation of the Tyndall Report will report on the findings Tyndall in a blog entry soon.
Photo: Ed Wade
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