The Slickwater Story

The reemergence of a simple frack design is increasing production, lowering well costs and impacting water usage in the Bakken. Slickwater fracks have become a go-to option for many Bakken operators.
By Luke Geiver | July 14, 2014

The timeless adage, “What’s old is new again,” now applies to the Bakken, thanks to the oil industry’s adoption of slickwater fracking. The fracture method that relies on high volumes of water and minimal chemical additives has been the recent buzzword during investor calls and industry events this year. Slickwater fracks were used before gels and high viscosity fluids became the industry norm for conventional and unconventional fracking designs, but the simple design of a slickwater frack has proven to produce a more complex fracture network in the middle Bakken formation.

When Halcon Resources reported a record initial production rate for a well in the Fort Berthold Indian Reservation in a June presentation, slickwater fracks were recognized as the reason for the record. Oasis Petroleum has already said that in the second half of 2014, 60 percent of all new Oasis wells will be completed using slickwater fracks after test results revealed a production increase of nearly 25 percent over wells completed with other methods. Triangle Petroleum Corp. said it has increased production by as much as 40 percent with the combination of cemented liners and slickwater fracks and reduced well-completion costs by $400,000 per well thanks to slickwater. Liberty Resources II, the exploration and production firm considered a leading-edge completion designer, has gone almost exclusively to slickwater fracks. And Lynn Helms, director of the North Dakota Department of Mineral Resources, said earlier this year that one of the major trends his office is seeing is the use of more water (slickwater) in frack jobs performed in the state.

To describe the impact of slickwater frack usage in the Williston Basin, we spoke with personnel in the main sectors of the play affected by the Bakken’s latest trend: an operator, a water provider and an energy services firm.

In 2010, several industry veterans co-authored a Society of Petroleum Engineers paper on slickwater fracks titled, “Slickwater Fracturing—Food for Thought.” The authors, Terry Palisch, global engineering advisor for Carbo Ceramics, Mike Vincent, founder of Insight Consulting, and Pat Handren, well integrity manager for Denbury Resources, described the motivation, benefits and concerns surrounding slickwater fracks. Their findings, according to Palisch, still apply today.

Slickwater fracking designs are typically deployed for three reasons, the authors wrote. First, some operators are looking for cost-cutting measures due to low commodity prices The water-based design of slickwater frack doesn’t require the use of many additives. Second, the reservoirs being fractured might be depleted or feature lower permeability. In such cases, nonslickwater methods are not able to clean up or wash out the gels used in the fracturing process from the tiny rock fissures. Third, completion teams recognize that fractures created using conventional methods may not always  perform as well as expected and that slickwater fracks can provide the same production result at a lower cost.

Although the authors did not mention a fourth reason, many operators and industry members believe the true merits of the slickwater frack is its ability to create a complex fracture network not possible without the use of the highly-pressured water. The main goal of a slickwater frack, regardless of cost considerations in accordance to other fracture treatment options, is to create an adequate fracture geometry in low-permeability, large net-pay reservoirs, according to the 2010 paper. Adequate, in the Bakken’s case, translates to better, most operators and slickwater-backers believe.

The basics of the method involve water combined with a polyacrylamide friction reducer. The slickening agents reduce the friction of the water in the pipe and the viscosity of the fluid. Because the fluid is less viscous and the water is lighter, more volume is needed to carry the same amount of proppant to effectively prop open the fracture networks responsible for draining the reservoir. Higher rates of pressure are also required to move the water. Pumping rates of 100 barrels per minute are common—a much higher rate than other unconventional fracturing pumping method requirements. The high pressure needed to perform a slickwater frack also helps to stimulate more rock and create more fractures. The absence of gel also allows for a quicker and easier placement of proppant into the fractures allowing the hydrocarbons to flow back quicker.

Of all the concerns about slickwater treatments, the greatest is the water volume required. Because the Williston Basin is situated in a geographic region with an abundant water supply, operators are able to deploy the method without incurring high water costs. The amount of water needed to perform a slickwater frack job typically exceeds 4 to 8 million gallons. In some cases, the quantity of pumping trucks used to inject the pressurized water into the wellbore needs to be doubled. Because the fluid treatment doesn’t rely on additives, slickwater fracks are more conducive for produce and flowback water recycling efforts, the authors also wrote.

Success With Slickwater
Since Halcón Resources first entered the Bakken oil play in 2012, the exploration and production company’s story has been characterized by two phrases, says Kelly Weber, director of corporate communications. “Our story is of rapid growth and production success.” In the past two years, Halcón has grown its Bakken oil production numbers from zero barrels of oil per day to 43,000. The company’s Denver office focuses exclusively on the Williston Basin. Two years ago, the offices were staffed by fewer than 10 but today’s count is more than 60.

The company’s rapid growth is linked to an entrepreneurial spirit championed by Floyd Wilson, chairman and CEO, says Charles Cusack, Halcón’s chief operating officer. “We have a lot of people that think outside of the box and find ways to get things done,” he says. Wilson started Halcón Resources only a year removed from the sale of his previous exploration and production company, Petrohawk, to BHP Billiton. Cusack was also a part of the Petrohawk team. “It was a challenge in the beginning of Halcón until we got the right people in place,” Cusack says of Halcón’s early days. “From a technical standpoint, it is always a challenge to figure out which completion recipe works in each area.”

After purchasing acreage from another exploration and production company operating in the Williston Basin, Cusack and company have not only proven how to successfully execute an entrance in the Bakken, they have has also found a way to make positive headlines. To turn its good wells into great wells in the company’s Williams County, N.D., and Fort Berthold Indian Reservation acreage, Cusack and his team have joined the growing list of operators who have turned to slickwater fracturing completions to get things done. The completion recipe has Cusack and the team confident that it has solved at least some of the challenges of the Middle Bakken.

In June, Halcón reported that its new slickwater completions deployed in the Fort Berthold Indian Reservation had outperformed all other wells completed in the area using other methods. The results of the slickwater fracked wells yielded a new initial production of 4,224 barrels of oil equivalent per day. “It has been a game changer for us moving to slickwater fracks,” Cusack says.

Halcón first used slickwater fracks in Williams County. The completion methods used prior to slickwater were only economically average, he says, but the change to slickwater made the wells in Williams County more than economical. “After we tried it in Fort Berthold, we saw a step change result. We turned great wells into world-class wells,” he says.

Although Halcón is pumping the same approximate amount of proppant into the slickwater wells, it is pumping much more water. The result provides the desired outcome pursued by every other Bakken operator that has transitioned to slickwater fracks. “It creates a more complex, intricate frack network,” Cusack says.

Every Halcón well planned for the middle Bakken will use slickwater, Cusack says, and although the team is not yet convinced the approach is optimum for the Three Forks, the company is trying some slickwater completions in that formation as well. The industry’s explanation of why slickwater fracks are more productive varies, according to Cusack. From his perspective, the lower viscosity allows the lighter water fluid to move more quickly through the rock to be fractured, while also letting the proppant settle more easily and quickly than if a gel-based fluid were used. “Everybody just theorizes on how it works exactly, but the bottom line is that there is definitely a step change in our improvement.”

Halcón has certainly joined the slickwater believers, but it has also supplanted itself as a major Bakken player by taking action to evade certain challenges other operators have found to be unavoidable, particularly the harsh operating conditions present during a Bakken winter. During the winter of 2013-’14, Halcón’s Bakken team wasn’t as affected by snow, wind and extremely cold temperatures. When the company acquired its properties in 2012, the local team immediately performed weatherization measures on its properties and equipment. According to Cusack, the company did not show any ill effects of winter weather because it also was able to offset producing or planned wells that were slowed by weather based on its higher than usual IP wells brought online in the winter. The wells were completed using slickwater. Even if slickwater may be linked to several facets of Halcón’s recent success, Cusack says his team isn’t done experimenting with better alternatives for completions, drilling techniques or any other element of the company’s overall operations.

“We will never sit on the status quo. We will never think we have all of the answers. I hope that when I talk to someone now versus a year from now that I can tell them about new records we’ve set and that we are doing more for less.”

Changes To Supply
The continued implementation of slickwater frack designs will increase the amount of oil retrieved. It will also alter the way water providers and infrastructure design and construction teams operate. AE2S Water Solutions currently designs water supply and takeaway systems for several operators in North Dakota. Grant Slick, principal engineer for the water and engineering firm, believes slickwater fracking will impact how his team designs and operates infrastructure. “In order to handle the amount of water needed to complete a slickwater frack, which is often in the range of 250,000-plus bbls there has to be greater focus on hydraulic modeling of the entire [infrastructure] system.” The enhanced modeling needs to include pipe size information, pumps and storage containers, all of which have to be part of the overall water supply infrastructure. The design of the entire system is necessary, Slick says, because when a well is fracked with a slickwater design, a high volume of water will be needed at the well site, but over time, the volume of water needed is drastically reduced.

Slick and his team are proponents of the pipeline system for fracking and well maintenance. “With the increased amount of water used, you are basically tripling or even quadrupling [assuming approximately 60,000 to 80,000 bbls needed for the frack job] the amount of truck trips needed to deliver the freshwater to the well pad,” Slick says. “The economics for putting in a pipeline certainly are more favorable with the increased water use, but there are also other variables at play such as geography from source to end use, topography, quantity of wells served and other parameters.”

Slickwater fracking requires Slick and his team to rethink the quality and quantity of the components it considers when designing a water supply or takeaway system, he says. The team does have systems currently operating south of Watford City that supply water for traditional fracture designs as well as slickwater. The system also gathers produced water.

The rise of slickwater fracking methods may be the hot topic now, but for Slick it won’t always be the most important. “Maintenance water over the lifetime of the well can actually add up cumulatively to quite a bit of water,” he says. Some areas of the Bakken may not need fresh water for well maintenance flushing, while others could require as much as 100 bbls per day per well. According to Slick, if an operator installs both produced gathering pipelines and freshwater pipelines, the system could operate on a closed loop cycle. Recycled water taken and treated from the gathering line could be reinjected into the freshwater pipeline. “Although recycle is in its infancy, proactive infrastructure planning can reduce the investment later.”

Author: Luke Geiver
Managing Editor, The Bakken magazine