The water-energy nexus in the oil & gas industry
It has now long been recognized that the demand for energy and water are tightly interconnected and that interventions to increase the efficiency on the use of one of these resources will impact the other, often in unintended ways.
Unconventional hydrocarbon extraction plays an increasingly important role in the global energy system. The most common methods for unconventional oil and gas extraction include hydraulic fracturing and mining and in situ techniques (oil sands). A common theme on these developments is the public concern with the energy (and therefore, GHG emissions) and water intensive nature of these operations. Produced water treatment operations, required to protect the environment and recycle more water, increase the cost and the energy requirements to extract these resources. Process design and operating decisions related to minimizing environmental impacts from these operations are complicated by these important trade-offs. A number of researchers have been exploring these questions for some time using modeling and optimization tools, with limited success in industrial deployment.
A recent seminar around water challenges in the oil and gas industry was held in Calgary, AB. The event invited presentations from industry and Government to reflect on industry actions to address these challenges, particularly under the current economic conditions of low and volatile commodity prices. It was noted that many areas in North America are experiencing severe drought conditions (e.g. the State of California issued a number of warnings this year) which are likely to get worse due to climate change. Hydraulic fracturing needs significant volumes of water (10,000 to 60,000 m3/well) and oil sands extraction depends heavily on abundant water supplies for bitumen extraction.
A systems approach is required to allow better decision making in industry and account for all of these interactions in a systematic way. Water sourcing was also described as a challenge; with water restrictions in place, opportunities to reuse municipal wastewater by industry have started to become interesting for some facilities. Water sourcing selection criteria include environmental impact, stakeholder relations, availability, timing, quality and economics. A particular technical challenge that may limit the use of some water sources is that of "compatibility" with reservoir characteristics- scaling could become a major problem if ignored. It was stressed that finding adequate water sources to enable production is similar to exploration for oil & gas itself, it needs proper resources for well testing, technology evaluations, etc. Risks to industry due to water availability are significant and need to be added to those associated to carbon emissions due to climate change concerns.
Process Ecology is working together with researchers at the University of Calgary to develop improved engineering methodologies to assist industry in understanding the trade-offs and uncovering holistic solutions to these major challenges. For more information on our progress please contact us.
