Strategic water management in unconventional oil & gas plays
Oil and natural gas plays an important role in meeting growing energy demands around the world due to its widespread availability, ease of transport, and the available infrastructure to handle these fuels. The growing world energy demand has led to exploration and development of unconventional natural gas resources such as shale gas and shale oil. Technology developments in hydraulic fracturing and horizontal drilling have changed the landscape of oil & gas production with countries like the USA becoming net exporters for the first time in decades.
The drilling, completion, and hydraulic fracturing of wells require large volumes of water, in some cases well over 50,000m3 and larger fracks are expected to be the trend. Water must be supplied in a short time period and usually over significant distances. A major challenge for producing companies is to develop strategies to deliver the required water, including options for recycling, use of alternative water sources, and the final disposal of wastewater at minimum cost. Multiple reports indicate the exponential growth experienced in water demand as the most productive plays are developed1,2,3. Increased freshwater use for these operations has prompted regulatory agencies to seek policies to reduce environmental impacts. The Alberta Energy Regulator (AER) reported that in 2016, hydraulic fracturing companies used 7 million cubic metres of non-saline water (11 percent of all water allocated for hydraulic fracturing).
Water management in hydraulic fracturing operations is a complex problem that involves a number of techno-economic and social dimensions. The decision-making processes currently in use by operating companies are ad hoc and rarely apply a systematic view of the problem to develop optimal strategies.
Common issues for water management include the identification of water sources near drilling sites, timing of the developments and the availability of water at the place and time required, seasonal variation in water availability, complexity of acquiring permits for usage of fresh water, identification of wastewater disposal options and ever-increasing transportation costs. Increasing regulations on fresh water use and the tightening of water disposal limits have forced industry to look for cost-efficient methods to handle water. In short, without having water where you need it, when you need it and in the right volumes, hydrocarbon extraction and consequently cash flow will be curtailed.
Process Ecology, in collaboration with Golder and Stantec, has developed HydrOpti, an innovative cloud-based software that relies on powerful algorithms to identify optimal water management plans to ensure the most efficient use of water resources at minimum cost.
HydrOpti takes into account the time and spatial dimensions of the problem to identify the least-cost water sourcing strategy to ensure that there are no water shortfalls due to insufficient storage, transportation or source availability. Similarly, it incorporates storage requirements to avoid the oversupply scenario where there are not enough options for disposal. Problems in the design of the water management strategy can result in delays in development activities with significant economic penalties and resulting in higher operating costs.
The proposed area-based regulations currently under definition in Alberta would require various operating companies to collaborate and share information regarding water use. The full-scale development from various operators could lead to conflicts in water availability. HydrOpti provides the means to evaluate alternative development plans, inform decision makers, and ensure sustainable development of the resources.
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1 Managing the Increasing Water Footprint of Hydraulic Fracturing in the Bakken Play, United States, Environ. Sci. Technol., 2016, 50 (18), pp 10273–10281.
2 Recent Trends in Water Use and Production for California Oil Production, Environ. Sci. Technol., 2016, 50 (14), pp 7904–7912.
3 Hydraulic Fracture water usage in Northeast British Columbia: Locations, volumes and Trends. Geoscience Reports 2012, British Columbia Ministry of Energy and Mines, pages 41-63.
