Until recently, water has not played a critical role in the economics of developing a well in the oil and gas industry. Now water plays an integral role in drilling, completions, production and all other aspects of well development, and E&P operators are faced with numerous costs involving the sourcing, transfer, storage and disposal of large volumes of water. The issue of water will continue to emerge as one of the leading obstacles for modern production companies to consider. Efficiency and economics have always driven innovation and developed technology and solutions for the challenges of the industry—it is no different with the water challenges operators are confronted with today. The increasing lateral length of wellbores continues to bring added efficiency to production and development but with a cost of increased water demand.

Life cycle of water in the oil field

As fracturing jobs become bigger and lateral lengths continue to increase, more water is needed and at an increased cost for operators. A fracturing job in the Permian Basin often requires more than 500,000 bbl of water, if not twice that amount, depending on the lateral length. A large service company recently released information showing an internal push for operators to invest in building “super pads” that contain 24 to 40 wells in one location. Quick calculations can indicate just how much water is being handled at these locations, and the demand is only going to grow in proportion to the needs of hydraulic fracturing operations.

Not only is more water being pumped downhole, but the industry also has seen an unprecedented amount of water usage once wells are in production, specifically in the Permian Basin. Water-oil ratios can range from as low as 3:1 for some wells in the Rockies to as high as 15:1 in the Permian Basin. For every unit of oil or gas produced, wells are generally producing significantly more water, and traditionally, this water has been disposed of in saltwater disposal wells.

Depending on fault lines and disposal depths, there have been seismicity issues related to water disposal, particularly in Oklahoma. The West Texas region also has experienced more seismicity with increased activity levels. A looming question for the industry is what future regulations will look like for water disposal. The process to obtain a permit to drill a disposal well has increased significantly in the last few months. In addition, trucks with loads of water are often taking hours at a disposal site to offload due to the number of backlogged trucks in line at the facility. Some worry and speculate that the industry will reach the capacity limitations for these wells.

With all of the water issues, most oil and gas operators have a team of engineers dedicated to developing solutions that are cost-effective for their operations when it comes to handling all water logistics, sourcing and disposal. Not only are these teams actively evaluating cost-effective solutions, but they are also researching environmentally responsible solutions.

Trucking results in higher traffic, resulting in elevated levels of emissions as well as increased potential for vehicle accidents in the respective communities in which operations are underway. Being able to reuse water close to the source, piping water or centralizing water treatment facilities can greatly reduce the amount of trucking required for water disposal purposes and has a positive environmental impact on the surrounding community. How an operator’s water is transformed and what specific treatment is needed varies by case. The plan of action for water treatment is dependent upon the volume and the quality of the water produced. Several options for proper treatment exist in today’s water market that allow cost-effective and environmentally sound solutions for operators.

Water quality and technological application

When it comes to the water resources needed for fracture design and reservoir, oil and gas operators are still trying to determine what the best key performance indicators should be for water quality. Gradiant Energy Services (GES) recognizes the need to treat water at various water quality levels. As a result, operators have a choice when it comes to treatment level and pricing level to reuse produced and flowback water for future fracturing operations.

For example, an operator can utilize freshwater or produced water for a fracturing operation. In either case the water has to be treated for bacteria. One option available is Free Radical Disinfection (FRD). This oxidizing disinfection technology is a safe, environmentally friendly bacteria treatment solution. FRD uses electrolysis to generate a mixed oxidant solution, including multiple free radicals, which is injected into the water stream. Operationally, it is manned by one individual that works alongside the fracturing crew, treating up to 120 bbl/min. The oxidation reduction potential level of the water is increased using the technology at a fraction of the cost of traditional chemical biocides.

The GES’ clarifier separates the solids from liquids during the recycling process. (Source: Gradiant Energy Services)

 

The next level of treatment encompasses recycling to a clean brine, which can potentially be achieved through many traditional water treatment techniques. However, not all of these techniques can be achieved consistently due to changing influent water qualities as seen in oil and gas produced water. GES’ Selective Chemical Extraction (SCE) technology has provided operators with water that consistently meets specifications. Challenging parameters such as iron have been treated with the system to levels of 0.5 ppm. The chemical precipitation process is controlled through an algorithm, which GES engineers utilize with a chemical plan to reduce chemical consumption and cost. The clarifier removes solids from the system unlike traditional systems.

Water quality can still be achieved to yet even a higher standard through GES’ Carrier Gas Extraction desalination system. This system uses a technology of the bubble column to replicate the humidification/ dehumidification that occurs in a natural rain cycle. Throughout the process, water is purified to a level close to that of drinking water. The system provides operators with an option to not only recycle water during fracturing operations but to potentially reuse the water for agricultural purposes.

Finally, operators that face disposal restrictions have turned to GES to utilize evaporation technology. The Carrier Gas Concentrator (CGC) achieves evaporation by multistage bubble column humidification at high rates of heat and mass transfer. CGC technology not only requires less energy than traditional evaporation, it does not heat the water directly, which allows minimized emissions. CGC provides a safe, cost-effective and environmentally friendly option to dispose of wastewater by evaporating the water and releasing the water vapor into the atmosphere with a deployable, mobile system.

Looking ahead

Technology and efficiency will continue to drive innovation within the oil and gas industry. Efficiency is critical in drilling and completions as well as in the arena of water usage and disposal. As the oil and gas industry continues to learn more about how water quality impacts its wells and reservoirs, the industry can expect technology to provide welcome assistance in shaping how water is handled from sourcing, storage, transfer and disposal. The volumes of water the industry is handling are significant, and the responsibility to handle water cost effectively while being mindful of the environment will become increasingly important to the industry and the communities it operates within.