Further opportunities, challenges and considerations for shale gas
Scarcity of drilling and fracturing equipment in Europe
In 2012, the number of land rigs available in Europe was 72 compared to around 2,000 rigs in the US. The majority of the US rig fleet is being used locally, so European drillers would have to commission new equipment. Each rig takes an average of nine to 12 months to assemble, and this is a capital-intensive process. Unconventional gas production requires the drilling of many wells in a short time period to make it economically viable.
Production technology development
Currently, the maximum gas recovery factor from shale gas reservoirs is very low compared with conventional reservoirs. Continued innovation and development of production technologies could increase this recovery factor. Having more efficient production technologies could reduce the number of wells needed to produce the gas, reduce the amount of water needed per well, and reduce the number of truck movements. Such efficiency improvements are currently under development.
Monitoring the construction of wells
Well construction is one of the key aspects in avoiding environmental issues, such as groundwater contamination by hydrocarbons or other substances. Standards exist for casing design and performance, as well as cementing quality control. Transparent monitoring of well construction can help provide assurance and manage environmental risk.
Monitoring water quality around producing wells
The monitoring of water quality will be an ongoing activity for UK regulators and shale gas operators, and a key concern for local communities. Some regulators in the US require monitoring of water quality pre- and post-fracturing in gas-producing areas. In the UK, the BGS has carried out work to establish a baseline for groundwater monitoring and protection. The latest data is available on the BGS website.
Enhancing water management
Fresh water is a limited resource. Several aspects of water management are being improved to minimise the impact of hydraulic fracturing on fresh water resources.
These include sea water sourcing and the re-use of flowback fluid, and the use of non-water based fracturing fluids, such as gels or gases. Other water management issues under consideration include transport and composition disclosure, storage, treatment, and disposal.
Improving methane emissions management
Methane emissions could counteract the potential reduction in national emissions from using shale gas instead of coal or oil. Estimates of the volume of methane leaked or vented during the production and transportation of natural gas vary widely, particularly for shale gas wells. This is due to a longer well completion and stimulation stage than for conventional wells.
This is predominantly a data acquisition and management problem. It could be solved by regulators requiring operators to identify leaks, leading to the capture of emissions (e.g. through reduced emissions completions).
Discussing and understanding legislation for unconventional oil and gas exploitation
Some experts believe that the UK has strong existing oil and gas legislation that could be applied to new unconventional oil and gas exploration and production fields. On the other hand, some organisations, including several NGOs, are unsure if the current legislation is sufficiently strong to avoid further environmental or public health issues. Further work is required in this area because a strong regulatory framework is necessary for ensuring ensuring responsible shale gas development.
Enhancing information exchange
The production of unconventional hydrocarbons can be divisive. During the last few years, various parties and interested groups have raised serious concerns about hydraulic fracturing and shale gas operations.
Dialogue between all parties is needed to ensure that local communities are well informed, understand the issues and opportunities from hydraulic fracturing operations, and are able to voice their concerns to regulators and operators.