The Environment Agency has published a useful technical guide on the monitoring of methane at unconventional gas exploration facilities to produce shale gas via hydraulic fracturing.

The study Considerations for quantifying fugitive methane releases from shale gas operations - provides invaluable technical background for companies and organisations interested in developing technologies, equipment and services needed for shale gas production. If hydraulic fracturing – fracking - takes off in the UK, strong regulatory requirements will be put in place to ensure safe water use at all stages in the fracking process.

Each individual application must go through the local planning authority process and before any drilling occurs, an application for authorisation for any discharge must be made to the Environment Agency or Scottish Environment Protection Agency in Scotland, which will only be granted if the agency is confident that there is no risk to the environment, and in particular to drinking water. As part of the process, operators are required to disclose the content of fracking fluids to the Environment Agency. The Health and Safety Executive will also scrutinise the well design for safety.

Upon completion of hydraulic fracturing a combination of fracturing fluid and water is returned to the surface (flowback). The flowback contains a combination of water, sand, hydrocarbon liquids and natural gas.

Equipment used at conventional gas wells under production conditions, including the piping, separator and storage tanks, are not designed to handle this initial mixture of abrasive fluid. Past practice in the USA has been to vent or flare the natural gas during this step, and direct the wastewater into ponds or tanks. New rules introduced by the USA in 2012 now require the use of reduced emissions completion (REC) techniques (also known as green completion) to control methane emissions during completion at the majority of unconventional gas wells. REC involves the temporary installation of equipment designed to handle the high initial flow of waste water, and to collect the gas for transmission to the gathering pipeline, or flaring if pipeline connections are not available.

The quantity of methane emitted during completion depends on the level of methane in the water flowback, the quantities of water flowback, the length of the flowback period and the management practices that are applied. Methane can also give rise to other pollutants, such as low-level atmospheric ozone, or chemical oxygen demand in watercourses

The Environment Agency’s Monitoring Certification Scheme (MCERTS), which sets performance criteria and standard requirements for equipment, personnel and companies involved in environmental measurement, currently includes the following provisions for water monitoring:

• Equipment for continuous monitoring of discharge
• Direct toxicity assessment of effluents and/or receiving waters
• Portable monitoring equipment
• Sampling and chemical testing of water
• Self-monitoring of effluent flow
• Radioanalytical testing of water

However, currently there is no specific category for undertaking measurements associated with the measurement of methane from unconventional sources.

The study makes the key point that it does not provide complete guidance on monitoring techniques because "developments in monitoring technologies can be expected to bring new monitoring techniques to the marketplace that are not available at the time of writing."

Click here to download the study.