Addressing the Environmental Risks From Shale Gas Development - Article Example

Article Critique “Addressing the Environmental Risks from Shale Gas Development” by Mark Zoback, Saya Kitasei and Brad Copithorne, July Worldwatch Institute Briefing Paper 1 1. Article Introduction Shale gas production in the US has grown rapidly to reach 30% of all US Oil and Gas production in 2009. The growth of this industry has become possible due to two key new technologies, horizontal drilling and hydraulic fracturing. The article explains these two new technologies using illustrative simple diagrams and terminology. These risks in the shale gas drilling process are discussed in two parts. One set of risks are specific to the hydraulic fracture process used for shale gas production while the other set of risks apply to all oil and gas production activities where there is much greater operating experience. The last part of the paper shows that the environmental regulations for shale gas drilling vary from state to state and that there are areas of overlap between some of the state regulations and some federal laws. The paper suggests the need for a common set of regulations so that the best practices developed at one drill site can be applied across all projects. 2. Environmental risks specific to shale gas production 2.1 Seismic shocks The major concerns about shale gas production have been around the hydraulic fracture process where the shale rock is caused to fracture by hydraulic pressure. The cracks in the rock propagate 500 to 800 feet in all directions from the casing pipe and the effect is similar to an underground seismic shock. The fracture pressure needs to be monitored and controlled to prevent the cracks from spreading beyond the shale gas layer (page 4). The general concern with setting off such underground fractures is that the fissures may permit contamination of underground water aquifers that are used for drinking water (page 7). Most shale gas formations are found 4,000 to 8,500 feet below the surface whereas drinking water sources are rarely more than 850 feet deep (page 8). Seismic monitoring is an essential tool to ensure that the underground cracks do not spread beyond the shale gas formation. However, only 3% of around 75,000 hydraulic fractures carried out in 2009 in the US were seismically monitored (page 8). An additional concern is with such underground fracture may lead to earthquakes. The town of Cleburne, Texas has experienced several low intensity earthquakes under 3.3.on the Richter scale in 2008 and 2009 after the start of shale gas exploration in the area when the region has no recorded earthquakes in the previous 142 years (page 9). Preliminary studies do not find a definite link between shale gas exploration and these earthquakes but the concern remains. The paper does not say whether the hydraulic fractures in the Cleburne area were seismically monitored. 2.2 Fresh water usage and waste water disposal Hydraulic fracturing requires 2 to 8 million gallons of water per well fractured. Though water once used for fracturing can be reused by diluting with fresh water, the Barnett Shale project has used an average of 3 million gallons of fresh water per well and has drilled tens of thousands of such wells (page 12). Apart from the problem of using so much water in competition with other uses, there is the problem of treatment and disposal of contaminated water. The water pumped into the well has chemical additives. When it flows back to the surface it includes any sub-surface water that may have dissolved contaminants such as arsenic, benzene and mercury (page 10). The ‘flow back’ water will happen not just during the hydraulic fracture process but also during the gas production phase of the well. The water is presently being injected into underground saline aquifers but the number of such wells available is too small to handle the volumes of waste water (page 10). Municipal waste water treatment facilities in the area of the shale gas fields cannot handle this volume of water and are not designed for these contaminants. Treated municipal water is also discharged into surface water bodies like rivers and streams which cannot be acceptable for the shale gas waste water (page 11). In 2008 and 2009 there were significant spikes in the level of Total Dissolved Solids in a Pennsylvania river that supplies drinking water. This has been attributed to shale gas waste water being treated in the municipal water treatment plants and then being discharged into the river (page 11) It would have been helpful if the paper had included information on the waste water disposal process of all the waste water generated from the present level of shale gas exploration. 2.3 Chemicals used in the hydraulic fracture process Over 200 different types of chemical additives are used in hydraulic fracturing as thickeners, friction reducers, corrosion inhibiters and biocides depending on the nature of the shale formation and the pressures used for fracture (page 10). The compositions of these chemicals also change over time as this is still an evolving technology. These chemicals could be hazardous to public health in sufficient concentrations and it is important that the chemicals used at each drilling site are notified to the public health authorities. Current regulations require such notification only when more than 10,000 pounds of chemicals are stored at any site. A bill is being introduced in the US senate that requires disclosure of all chemicals used at a project site irrespective of quantity (page 10). Chemical contamination occurs not just in the waste water resulting from hydraulic fracture but also from surface water run-off from drilling sites and during transportation. The paper does not identify any of the chemicals used in hydraulic fracturing or report on any chemical contamination issues at the present shale gas production fields. 3. Other environment risks The paper also outlines the other environmental risks that are common with conventional oil and gas drilling including well blowouts (page 8), cement and casing failure(page 8), leakages from storage tanks and pipelines and venting of gases (page 12). The paper rightly points out that these issues have been managed for a longer time than the shale gas specific issues and there are well established safeguards from the Environment Protection Agency (EPA) and the American Petroleum Institute (page 12). 4. Regulatory framework covering shale gas development The paper highlights the need for a uniform set of regulations to apply to the shale gas industry. At present each state has its own set of regulations and certain federal provisions also apply. One example is the rules covering ground water contamination. State regulations require the level of the surface casing to be below the deepest groundwater but federal regulations cover storm water runoff and surface discharges from drilling sites (page 13). The federal Safe Drinking Water Act regulates underground injection of waste water from gas wells but does not yet cover waste water from the hydraulic fracture process. Some states are leading the way in framing additional regulations for the shale gas industry, notably Colorado and Wyoming. In New York state where shale gas is a comparatively new activity, there are multiple bills in the legislature and there are calls for a stoppage of all drilling until all regulations are in place. In neighboring Pennsylvania the governor has called for a three year moratorium on leasing of government land for gas drilling until environment impact studies are completed (page 15). The paper correctly points out that the absence of uniform regulations will prevent the implementation of best practices from one well site to another which is so essential in an emerging industry (page 14). 5. Conclusions The paper does an excellent job in presenting an overview of the shale gas industry and the specific environment risks associated with the hydraulic fracturing process used in shale gas production. The language used to describe the technology is easy to understand even for people unfamiliar with the oil and gas extraction industry and the good illustrations used in the paper improve the communication even further. The three major environment concerns, the seismic shocks, the water usage and disposal and the chemicals used are all significant and need close monitoring as the exploration for shale gas expands and more players come into the field. The paper highlights the need for a common well thought out set of regulations to apply to this industry in place of varying state regulations overlapping some federal laws. The paper would have even greater value if it had collected complete data on the environment issues that have surfaced at the various shale gas production sites around the US and the measures taken to address them. Instead, the article cites these more as anecdotal information. It would also have been beneficial to compare US shale gas exploration practices with, for example, the practice in Australia where a major shale gas production facility is operating. The paper, however, is extremely valuable and needs to be read by everyone interested in the industry including common people who live in the regions where shale gas exploration is happening. That area in the US covers 48 states. * * * * Read More