Water is the base fluid – and most important component – in the process of hydraulic fracturing for shale oil and gas development in North America. With the growing demand for fracturing, oilfield service providers face significant challenges to find and use water from nonfresh sources that will work effectively with their fracturing fluids while also minimizing the impact of their operations on the environment.

One significant change in fracturing operations is that the industry needs to use more water, which requires more efficiency. As a result, the industry is constantly getting more creative in how it manages its water to maximize efficiency in its operations while reducing environmental footprint.

Since water comes from produced, recycled, and other nonpotable sources, Sanjel Corp. developed a process to adapt to the wide range of water quality. After all, the fresher the water is, the easier it is to use. But fresh water can’t be used for all of the fracturing operations because it simply isn’t sustainable. The company is taking a practical and realistic scientific approach with its water management strategy.

Sanjel has invested in a team of chemists, specialized instruments, and analytical tools that allow the company to better understand the water, what is in it, and how that will impact the chemistry. The company currently offers two fluid systems that are compatible with produced water, recovered flowback fluids, and other non-potable water.

A crosslinked gel fracturing system was adapted for use with poor-quality water. Water analyses on submitted produced waters gave pertinent information on how to go about investigating hydration data as well as crosslink stability. By manipulating existing products and fluid systems, adequate polymer hydration was achieved, even in high-saline environments. With the additions and adjustments of current products to existing fluid systems, challenges of using poor waters were overcome.

By manipulating current products and foamed fluid systems, waters with high salinity were used to produce not only viscous foams but stable nitrified fluid systems. This allowed a polymer-free fluid system to be used with nonpotable waters as well. Base fluid viscosity was determined, and foam stability under well conditions was characterized. Fluid performance can be delivered to meet job-specific fluid-system criteria even when working with undesirable or saline base fluids.

Combatting changing water properties

The company’s chemical quality-control process helps combat the constantly changing water properties found not only between any two fracturing treatments but also between any two water tanks used in a single job.

Analytical tools are used to fully understand the properties of the produced water and see how it will affect the fracturing fluids. Every single batch is checked to make sure the fluid is performing the way it’s supposed to perform.

Sanjel’s expertise in understanding the properties of the water comes from both the technicians in the field and the staff at its technology center.

The R&D group looks at the water on a molecular level, really drilling into the science of the water. On the day-to-day operations side, staff members in the field take that knowledge base right to the customer and can then develop a customized product for the job in a very short period of time.

This enhanced understanding of the poorer quality water allows use of nonpotable water, including produced water instead of fresh water. In 2009 Sanjel was able to use produced water for its fracturing fluids for the first time. An operator in the Bakken formation in southeast Saskatchewan wanted to use a water source that was high in salinity and would have normally been sent for disposal. Rather than waste the resource, the produced water was characterized, and a custom solution was developed to use it for fracturing.

This project resulted in replacing approximately 96,000 bbl of fresh water every 12 days on 30 wells, which saved the operator significant costs in the purchase and transport of fresh water. Since the successful conclusion of that groundbreaking project, the use of nonpotable water for fracturing treatments has been steadily increasing. Today, between 80% and 90% of the fracturing done by Sanjel uses nonpotable water.

Sanjel’s understanding of water properties, chemistry, and the versatility of its fracturing fluids allows the company to regularly develop a customized product 24 hours after receiving a water sample from a client. When a water sample is received from the client, the company custom-designs the job based on that sample. Then it goes to the next well, where another sample is taken and another product is made.

Reducing environmental footprint

Aside from being able to effectively use nonpotable water, Sanjel is committed to minimizing its environmental footprint. The company has created its own in-house chemical rating system. The Sanjel Chemical Hazard Rating System (SCHRS) is based on the Globally Harmonized System of Classification and Labeling of Chemicals.

In the last year Sanjel has significantly reduced the hazard profile of its product line. A recently developed blend for acid jobs in the Eagle Ford region resulted in an SCHRS drop of more than 50% over the blend originally used in the area.

Sanjel will continue to work towards lowering SCHRS scores and improving efficiency using produced and recycled water. The company will continue to improve its chemical rating scores and make incremental improvements in its operations to use poorer quality water. This will allow the company to keep its costs down to customers while reducing the impact on the environment.

Sanjel is making investments in its water management program, allowing the company to minimize its freshwater use and environmental impact while maximizing its efficiency during fracturing operations. With horizontal well drilling depths now regularly exceeding 6,097 m (20,000 ft), the demand for resources, particularly water, is increasing.