As anyone within the industry can tell you, water is the upstream oil and gas sector’s most abundant by-product. Globally, oil and gas production have been estimated to produce in the region of 50 billion barrels of water per year – the equivalent of between two and three barrels of water for every barrel of oil. And it is a number that will continue to rise as long as the shale gas industry continues to grow.
For companies operating upstream, water management constitutes planning, developing, distributing and optimising the use of water resources. Within this important remit, arrangements must be made for water treatment (including drinking water, industrial water, sewage and wastewater), flood protection, irrigation and water tables, for a start.
Handling water in the oilfield can be a very complex, costly problem, but the costs of failing to do so properly can also be severe. Poor performance, excess down time, production cutbacks and environmental incidents can all come about as a result of inadequate or underperforming water treatment systems. Therefore a strong overall strategy is needed, and effective monitoring and maintenance regimes must be in place.
Although in many circumstances produced water can be reused, water unsuitable for recycling in this manner usually requires treatment to inhibit scaling and corrosion and to comply with environmental requirements prior to disposal or discharge to the environment. According to IPIECA, the global oil and gas industry association for environmental and social issues, “recognising that produced water may have an economic value is an important step in undertaking responsible water management”.
Typical components in a produced water stream – each of which may present its own individual challenge – include salts, oil droplets, dissolved gases, organic compounds, bacteria and other living organisms, solids, and other chemicals. The exact treatment methods used vary between different systems, and from location to location.
For many companies, the stated aim when it comes to the treatment of produced water is to return it to the environment cleaner than when it came out, but this goal is ever more challenging due to the need to treat larger volumes of water at lower costs whilst also staying on the right side of strict regulations enforced by bodies such as the US Environmental Protection Agency.
Neither can growing global concerns over access to fresh water be ignored: According to World Bank statistics, in over 80 countries the health of their people and economies are threatened by inadequate access to clean water for drinking and sanitation. Overall, water management strategies for the future will need to be flexible, sustainable, and provide measurable improvement in capital and operational efficiencies. ■
Adjacent Oil & Gas
From Adjacent Oil & Gas 5, November 2016