What is unconventional gas?
Unconventional gas is the collective term used to describe tight gas, shale gas and coal bed methane (CBM). In order to be developed and produced, most unconventional gas production requires the rock to be hydraulically fractured ('fracked') or stimulated to allow natural gas to escape from the tight rock and flow through the wellbore to the surface.
What makes it different from other fossil fuels, particularly natural gas?
There is no difference between unconventional gas and conventional gas. The difference lies in the reservoirs, where the natural gas is found, and some aspects of the process in which it is extracted.
What is unconventional gas used for?
Natural gas, whether it is extracted using conventional or unconventional methods, is the cleanest-burning fossil fuel and can be used to meet the energy demands of many sectors. When used for power generation, for example, natural gas emits up to 60 per cent less CO2 than coal. Emissions of other waste products such as mercury, sulphur and nitrogen oxide are also significantly reduced, improving air quality.
Can Europe mirror the U.S. unconventional gas ‘boom’?
On-going exploratory drilling has shown new and promising estimates of European unconventional gas resources, and extraction activities are gradually proceeding across the continent. The International Energy Agency (IEA) estimates there exists 19 trillion cubic meters (tcm) of technically recoverable unconventional gas resources in Europe.
Further exploration and technological advances will reinforce Europe's extraction capabilities and help bolster European energy independence, achieve greenhouse gas emissions targets and foster economic growth.
How does ‘fracking’ work?
'Fracking' is the general term used for the process of hydraulic fracturing, which involves pumping a pressurized mixture of water, sand and chemical additives down the wellbore and into tight rock formations that contain natural gas. The water pressure creates very thin cracks in the rock, which are then held open by the grains of sand, allowing the trapped gas to flow out through the wellbore to the surface.
How does the extraction process impact local communities?
Before any wells are drilled, extensive surveillance, monitoring and seismic analysis are conducted to study the locations of the underground natural gas reservoirs and to minimize the impact of operations on the local community.
To minimize traffic disruptions, trucks used to carry equipment and hydraulic fracturing fluid are brought in during the day, and usually at off-peak times. Though the noise levels from the site are well within the permitted range, noise barriers are sometimes set up around the perimeter of the area to reduce sound levels even further. Once an unconventional gas well is producing, it is extremely compact and quiet.
How long do drilling, hydraulic fracturing and production operations last?
The drilling stage takes a few months while the hydraulic fracturing, including the preparation work, lasts only up to one week, depending on the type of rock. The production life of the well, however, can vary from a few years up to 20-30 years. This depends on how much natural gas the reservoir contains and how much of it can be extracted at an economical rate.
Are costs higher for unconventional gas projects than for conventional gas projects?
Yes, generally the costs are slightly higher if a reservoir needs to be stimulated. Until recently, unconventional gas extraction methods were too expensive to be commercially feasible. However, recent technological developments have made the process economically viable.
What are the chemicals used in hydraulic fracturing and why are they needed?
Hydraulic fracturing fluid is typically 98-99.5 per cent water and sand, with the remaining 0.5-2 per cent comprised of chemical additives that are needed to make the process more effective. The additives are used to reduce friction, inhibit bacterial growth, prevent corrosion and enhance the fracture's effectiveness, thereby making the process safer and more efficient.
Many of the chemical additives used in the process are found in household products such as cosmetics, shampoo and cleaning products. Responsible operators employing hydraulic fracturing techniques, like all processes related to the extraction of unconventional gas, adhere to the highest European and national environmental and safety regulations.
Will chemicals used in fracturing fluid get into groundwater aquifers?
Hydraulic fracturing used for extraction of unconventional gas occurs far below the groundwater aquifer. European shale gas deposits are 1-3 kilometers below aquifers and all responsible operators implement a series of precautionary measures to ensure that none of the chemicals leak into groundwater aquifers.
The key to groundwater protection is proper well design; when a natural gas well is drilled through an aquifer multiple layers of impermeable steel and cement casing are used to ensure wellbore integrity. Verification of well bore integrity during all phases of operations is an important objective for safe and efficient production. These layers are tested for leak-tightness during all phases of operations, ensuring an impermeable barrier between the well and the water source whilst fluid is pumped to an area that is hundreds to thousands of meters away from the groundwater table.
A variety of testing procedures are implemented by industry throughout operations, including laboratory tests of cement behavior, pressure testing of well bore casings to verify their integrity, and a series of well bore casing inspections. There is no difference in this requirement between an unconventional gas well and conventional oil and gas well, and even geothermal energy wells, all of which have been drilled in Europe for over 100 years.
To ensure integrity of well bores a variety of testing procedures are implemented at ExxonMobil. Verification of well bore integrity during all phases of operations is an important objective for safe and efficient production. In order to achieve this goal, multiple tests for cement and casing integrity are conducted on a regular basis. For example involving laboratory tests of cement behavior, well bore pressure testing of all casings shoes to verify their integrity, and various well bore casing inspection logging runs.
The surface site is also designed to isolate the ground from the drilling and production operations to ensure any risk of fluids entering the ground is removed. These measures are heavily regulated in Europe, and apply to both conventional and unconventional gas wells.
What can you tell me about the reports of leakages on sites in the United States?
What can you tell me about the reports of leakages on sites in the United States?
There have been limited incidents where fracturing fluid and flowback water have been released on the surface due to wellbore integrity and surface facility water handling issues that were not related to the hydraulic fracturing process itself. While limited in scope, these instances are regrettable, as they can be avoided with good well design, adherence to industry standards and responsible work practices.
How much water is used to develop unconventional gas?
The amount of freshwater needed for drilling and fracking over the two to three month set-up, drilling and completion process for a typical well is usually equivalent to about three to six Olympic-size (50 meters by 25 meters) swimming pools. The hydraulic fracturing process itself uses a small amount of water compared to other industrial and recreational uses; coal mining, for example, requires two to four times more water per unit of energy produced whilst certain agricultural-based biofuels, such as corn-based ethanol, require 80 to 12,000 times more water per unit of energy produced.
What is done with wastewater?
Various treatment technologies allow the produced water to be reused for subsequent hydraulic fracturing operations and other industrial uses or to be disposed. Operators of shale gas wells, however, must first obtain permits for the handling and disposal of produced water under the EU Mining Waste Directive. After separating the wastewater and natural gas, water can either be stored or recycled at the surface; if no recycling occurs, the solid and liquid waste are stored temporarily in sealed containers and then shipped to licensed water processing facilities for treatment and disposal according to the permit procedures and applicable regulations.
What is the risk of seismic activity?
Unconventional gas exploration and production are one of many industries that can induce seismic events or above-ground movements/vibrations. Quarrying, tunneling, coal mining, geothermal energy production, industrial presses and heavy vehicle movements can all create nuisance vibrations.
Induced seismicity refers to seismic event of a magnitude that is generally too low to be felt by human beings (below 1 to 2 on the Richter scale). An earthquake, however, is considered to be an event above 4 on the Richter scale in highly tectonic areas where large active faults pre-exist.
There is no increased risk to the public, infrastructure, or natural resources from induced seismicity related to hydraulic fracturing. The microseisms created by hydraulic fracturing are typically around -1.5 on the Richter scale, thus too small to be felt or to cause damage at the ground surface or to nearby wells; it can be compared to dropping a 3 liter bottle of milk on the floor from shoulder level and requires extremely sensitive instruments for detection.
What about the seismic event in Blackpool, UK in 2011?
At Cuadrilla Resources' unconventional gas exploration site in Preese Hall UK, the company voluntarily suspended hydraulic fracturing activities in May 2011 after two seismic events in the Blackpool area (Magnitudes 1.5 and 2.3 on the Richter scale.)
According to the British Geological Survey "fluid injection, between depths of two to three kilometers, was on-going at the Preese Hall site shortly before both earthquakes occurred. The timing of the two events in conjunction with the fluid injection suggests that they may be related. It is well-established that fluid injection can induce small earthquakes. Typically, these are too small to be felt.”
In the subsequent UK Department of Energy and Climate Change (DECC) report, commissioned by Cuadrilla Resources, experts acknowledged the risk of induced seismicity below a magnitude of 3 on the Richter scale and that such events are "unlikely to cause structural damage" and "see no reason why Cuadrilla Resources Ltd. should not be allowed to proceed with their shale gas exploration activities and recommend cautious continuation of hydraulic fracture operations, at the Preese Hall site."
As part of the DECC report recommendations Cuadrilla Resources has commenced work to install sensitive monitoring technology so that it can undertake comprehensive seismic monitoring around its well sites.
What is the greenhouse gas footprint of unconventional gas?
Comparisons of life cycle greenhouse gas (GHG) emissions aim to calculate the emissions of greenhouse gases over the full life of energy resources, including all stages of fuel production and distribution, from extraction through the distribution and delivery and use of the finished fuel to the ultimate consumer, where the mass values for all greenhouse gases are adjusted to account for their relative global warming potential.
Comprehensive studies have been undertaken to assess the life cycle GHG emissions of unconventional gas in comparison to both conventional gas and other fossil fuels:
The U.S. Department of Energy completed a comprehensive study released in October 2011 estimating that the 'life cycle' GHG emissions of unconventional natural gas-fired baseload power production is 39 per cent lower than coal per delivered megawatt-hour (MWh).
A study carried out by Professor William Griffith et al. of Carnegie Mellon University concluded that the life-cycle footprint of shale gas is only 3 per cent higher than the average of domestic gas in the U.S., which is mainly due to the number of wells required per unit of gas produced.
Does unconventional gas development produce increased methane emissions?
Emissions of methane may occur following hydraulic fracturing and well completion during the 'flowback' of the well when some methane, hydraulic fracturing fluids (primarily water) and formation water return to the surface immediately prior to the well being put into production. There are several technological solutions that industry already uses to reduce methane emissions:
Reduced Emission Completion (REC) technologies, also known as "green completions", filter and capture this methane, so that it is not released into the atmosphere. Industry is working with suppliers to ensure that the availability of REC equipment keeps up with demand. Their installation in European shale gas wells will most likely be economical as the value of the gas captured is higher.
According to a recent study by the University of Texas, methane emissions from natural gas production are 0.42 per cent of produced natural gas, similar to the most recent estimates of the US Environmental Protection Agency (EPA). The authors found that at the majority of hydraulically fractured well completions sampled, industry has proactively imposed green completion technology which effectively reduced methane emissions by 99 per cent.
Will using unconventional gas affect emissions reductions targets?
Yes, it affects emissions targets for the better as on a well-to-wire basis it produces up to 60 per cent less CO2 for power generation than coal - thus lowering emissions. Natural gas, including shale gas, is a critical fuel to Europe's energy transition as the Commission stated in the Energy Roadmap 2050; coal-to-gas switching has been the largest contributor to Europe's 11 per cent emission reduction since 1990 levels.
A study by IHS CERA calculated that emission reductions of up to 58 per cent could be realized by simply replacing all oil- and coal-fired power plants with best performance combined cycle gas turbines (CCGT).
Who regulates unconventional gas development?
In addition to European, national and local regulation, unconventional gas development adheres to a wide range of recommended industry best-practices and standards to ensure safe and environmentally responsible operations.
The European Commission's 2012 'Final Report on Unconventional Gas in Europe' concluded that shale gas exploration is covered by a range of EU and national legislation and that there are no significant gaps in coverage in the current EU and national energy and environmental legislative frameworks for regulating the exploration of shale gas activities.
How are local communities engaged in the unconventional gas development process?
Local communities are an essential contributor to the unconventional gas development process. As a normal part of the environmental/well/drilling process, exploration companies work closely with local communities to ensure that development activities do not negatively impact the community's safety, economy or environment; this is done through on-going community outreach programs that establish dialogue with local communities in the area of a potential drilling site at every stage of operations. Transparency regarding the exploration and extraction of unconventional gas ensures open discussion about environmental protection and risk management, and the potential benefits of shale development in Europe.
Are the chemical additives used in the hydraulic fracturing process publicly disclosed?
There is a robust regime in place for regulating chemicals in Europe under the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) Regulation. All chemical substances meeting the one metric ton threshold must be registered at ECHA (European Chemicals Agency) by the manufacturer or importer, and registration files for substances must include the correct exposure scenario.
While there is no specific identifier on REACH forms for 'hydraulic fracturing', service providers have been using the 'oil and gas extraction' category. Most reputable exploration and production companies active in shale gas exploration in Europe already disclose information on their company websites.
Are European well designs and casing standards safe?
The key to environmental protection is proper well design and casing. To avoid disruption and ensure protection of, for example, groundwater, multiple layers of steel and cement casing line the wellbore to create several impermeable barriers, and they are regularly tested for leak-tightness throughout operations.
The surface site is designed to isolate the ground from drilling and production operations, and responsible companies implement rigorous safety standards and procedures throughout operations to ensure any risk of fluids entering the ground is removed. The process is heavily regulated in Europe, and responsible operators around the world adhere to the highest well design standards.