Shared Groundwater Resources

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Minimising impact to shared groundwater resources 

Efficient water management is vital to the success of our Onshore US operation, within our Petroleum Business, particularly given we share the regional groundwater resources with local communities and other industries.

General public concerns have been expressed regarding the potential for contamination of groundwater resources during drilling and hydraulic fracturing, as well as during oil and gas production. The use of chemicals and additives during hydraulic fracturing can, if not carefully managed, impact local groundwater quality and introduce risks to local community drinking water. Excessive withdrawal of groundwater during well completions may impact other users of groundwater wells.

Our priority is to always operate hydraulic fracturing activities safely and in an environmentally responsible way. We actively engage with local governments and communities to address public concerns. We conduct environmental assessments prior to our hydraulic fracturing work to minimise the impacts of our operations. In FY2015, we updated and improved our water balance model to help find ways to reduce water consumption.

As part of our water target commitments, we are pursuing non-potable water options for drilling and completions, including brackish water and recycled water produced from our production wells.

At our Permian operations, we predominately use a blend of brackish water and recycled water for drilling and completions. Permian achieved a 30 per cent recycling rate in FY2015 by replacing fresh water with 2.2 million barrels of produced water that would have previously been disposed. At our Eagle Ford operations, a mobile reverse osmosis system is used to produce potable water and treat waste water for reuse, thereby saving fresh water and reducing the trucking of water and waste.

We practice safe handling, minimisation and recycling of drilling residuals. We publicly report the ingredients of the fracturing fluids for each well completion in the hydraulic fracturing chemical disclosure registry, FracFocus, and disclose the maximum percentage of each ingredient presented in the fracturing fluid mixture.

We also implemented a Groundwater Risk Management Plan, which incorporates controls to prevent the loss of containment of pressurised fluids, including casing annulus monitoring procedures to verify well integrity; proper well head and casing design and construction; and specialised training to assure competency. Additional controls to ensure well integrity include pressure tests of the casing at each section, cement evaluation and formation integrity testing of the casing shoe.

During FY2015, we voluntarily implemented a pre-drilling groundwater monitoring program in the active drilling areas of the Eagle Ford, Permian and Haynesville shale operations to establish a baseline of groundwater quality.

We accept the scientific basis for linking seismic activity to waste water injection wells associated with unconventional oil and gas production. As such, we conduct enhanced seismicity monitoring and other types of data acquisition to better understand and mitigate the risk of the potential for induced seismic activity associated with waste water disposal operations.

We actively participate in cooperative efforts with stakeholders (industry, government, science community and the public) to better understand and promote best practice risk management in our operations.