By Jeff Gunderson
Recent advancements in hydraulic fracturing and directional drilling have made a profound impact on the North American oil and gas industry, enabling for resource extraction from tight and impermeable sources that in the past were largely inaccessible or not economically viable to produce. The availability of these novel production technologies has helped drive a boom in shale and unconventional sources, leading the U.S. to become the world's largest natural gas producer in 2009. That same year, oil production across the nation surged and has climbed higher every year since.
While allowing higher performance standards in oil and gas recovery, hydraulic fracturing and horizontal drilling are also much more water intensive as compared to conventional completion processes, generating significant quantities of complex flowback and produced water. As energy demands continue to rise and exploration and production (E&P) activities expand to meet this need, water management issues are projected to become increasingly more challenging, requiring solutions that are both strategic and effective.
Although treatment requirements in the U.S. are not as robust as in other markets, water management is still a key concern among E&P companies simply because of the tremendous volume requirements associated with fracking, said Ashish Aneja, advanced technologies leader with GE Water & Process Technologies.
"The focus in the U.S. is more towards applying minimal treatment with the right chemistry, which allows flowback and produced water to be reused in the next fracture, thereby minimizing the trucking that may be required for hauling water," he said.
Aneja also noted that compared to the U.S., stringent requirements are driving the use of advanced technologies in other markets -- such as Australia and Canada -- with significant unconventional operations.
"In Australia's coal seam gas industry, mandates are in place requiring that water is taken all the way to zero liquid discharge," he said. "We have a strong presence in that market with ultrafiltration, reverse osmosis, and evaporation and crystallization technologies. Additionally, we are also positioned in the oil sands of Alberta, Canada, where advanced treatment is utilized to treat produced water resulting from steam assisted gravity drainage processes."
Devesh Mittal, vice president and general manager for Aquatech's Energy Service Division, added that water issues in the U.S. are extremely localized and the drivers that influence water management strategies in shale production can change very dramatically from region to region. "In Texas, where water supplies are stressed, water sourcing risks represent the main driver for recycling and reuse, but in other regions, it can be markedly different," he said.
An example is the Marcellus Shale in the state of Pennsylvania where water access is relatively abundant, but due to poorly-suited geologic conditions that restrict the availability of deep well disposal, wastewater must be trucked long distances to deep well injection sites in the states of Ohio and West Virginia.
"In Pennsylvania, trucking costs associated with transporting source water and wastewater can account for over 70 percent of the total water management costs for each well," Mittal said. "In evaluating the cost savings to the round-trip cost of water -- which takes into account costs associated with water acquisition, transportation, storage, treatment, and disposal -- the economic benefits of recycling and reuse can be a very strong driver."
But in order for recycling and reuse to make practical and financial sense, Mittal said sufficient drilling activity must also be present, creating continuous opportunities for wastewater to be reused. "This enables for water management savings, which justify the investment costs for infrastructure and storage necessary to manage a recycling and reuse program," he said. "These investments are the most cost-beneficial when a healthy sum of direct economic, public relation, regulatory compliance, and environmental returns are provided."
Improving Water Management Operations
Across the industry, efforts are being made to develop new technologies, tools and solutions that address mounting water-related challenges in shale and unconventional energy development.
"Shale production activities and issues associated with hydraulic fracturing, water usage and deep well disposal have really brought the industry under the public eye," said Kent Perry, vice president of onshore programs for the Research Partnership to Secure Energy for America (RPSEA), a non-profit organization established by the U.S. Department of Energy. "The footprint created by shale E&P operations is very noticeable."
This heightened awareness combined with the need to mitigate water sourcing risks and reduce water management costs in shale operations are driving technical advancements and new initiatives that address these issues, Perry observed.
"A whole portfolio of research projects [is] currently underway, from improving membranes and reverse osmosis to plasma technology and other innovations that can manage and process water in an efficient and effective way," he said. "One of the prevailing concepts is to develop technologies that can treat water to various levels, enabling for multiple targets of reuse. Efforts are also being directed towards identifying and recovering useful products from produced water such as salts, minerals and chemicals."
RPSEA is also developing a GIS-based tool in collaboration with Colorado State University that aims to optimize the management of fluids from unconventional gas production. The goal of the new tool is to enable sustainable gas production while minimizing potential impacts on natural water resources, public health and the environment.
"Based on a specific region and the number of wells that are planned to be drilled, the model will estimate how much water is available, how much water is needed for fracturing, and the projected amount of flowback water," Perry said. "Armed with that information, water managers can determine if enough water is available for reuse and if the quality is suitable for fracturing. The model will also provide information related to water transport, including locations where it can be hauled."
According to Perry, the tool is anticipated to be used in early planning and also as a real-time solution that will correct or modify as new and updated data are provided.
Maximizing Reusable Water Streams
In the Permian Basin of West Texas, Boston-based Gradiant -- formed out of the Massachusetts Institute of Technology (MIT) -- has commissioned two commercial treatment facilities based on the company's new treatment innovations that enable extremely high rates of water recovery with high automation and require substantially less energy and chemical use. Co-founders Anurag Bajpayee and Prakash Govindan invented their technologies at MIT from researching solutions that could address the most challenging water treatment problems.
The first facility, built in 2013 for Pioneer Natural Resources, utilizes Gradiant's carrier gas extraction (CGE) technology in combination with other complementary technologies to treat and convert 100 percent of shale flowback and produced water into reusable water resources. The second facility was completed in late 2014 for another independent oil and gas company and is based on Gradiant's selective chemical extraction (SCE) technology, which is also deployed in combination with complementary technologies to treat 100 percent of shale flowback and produced water, generating a clean, reusable brine.
"Both plants are 100-percent liquid recycling facilities, with every drop of water being allocated toward reuse," said Bajpayee. "The solutions offer significant, long-term savings by reducing disposal and procurement costs while insulating operations from the risk of drought and water-related disruptions."
The CGE process incorporates a continuous, atmospheric-pressure, ambient-temperature desalination technique that uses a carrier gas to extract fresh water from high-salinity brines. The SGE technology is a multi-step treatment process that can be customized to meet any effluent quality and is capable of oil and grease removal, H2S stripping, VOC and semi-volatile removal, ion-specific removal, and lamella clarification. The core of the SCE process is an ion-specific induced precipitation process utilizing proprietary chemistry that enables the preferential reaction and removal of targeted ions.
Gradiant is currently working on three additional technologies that would complement its existing solutions. "Our goal is to build a portfolio of technologies that can be applied based on regulatory and economic requirements and specific water attribute needs," said Bajpayee. "Solutions need to be customized since there's no ‘one-size-fits-all' in this industry."
About the Author: Jeff Gunderson is a correspondent for Industrial WaterWorld. He is a professional writer with over 10 years of experience, specializing in areas connected to water, environment and building, including wastewater, stormwater, infrastructure, natural resources, and sustainable design. He holds a master's degree in environmental science and engineering from the Colorado School of Mines and a bachelor's degree in general science from the University of Oregon.
