The Advantages of Unbundling Frac Chemicals

It’s no surprise that oil and gas producers are looking for the fastest way to maximize production. So, a pre-bundled chemical package from the pressure-pumping company may seem like the quickest, most costeffective approach to getting results.

• But does the one-size-fits-all approach work if the particular formation is known for fines generation?
• Does it address field-specific H2S concerns?
• Is oil recovery impacted by altering the wettability of the formation?
• Are detrimental bacteria being introduced to the reservoir due to an inadequate biocide program?

spwm boyd6Tailoring the completion fluid system to specific well conditions for fracturing operations ensures that each chemical produces the intended result, leading to increased production and lower treatment costs.

This should not be shocking. Customization always trumps cookie cutter—when building houses, when buying cars and especially when deciding on which chemistries to use to fracture a well.

Expert Evolution
Bosque Systems began in 2007 with a focus on meeting the need for more saltwater disposal wells (SWDs) in the booming Barnett Shale. The company soon began hiring experts in chemistry and engineering who developed testing and other approaches to treat water used in SWDs.

Bosque’s goal was to control the level of contaminants in the water to extend the life of the reservoir beyond the industry standard. In 2010, the company expanded to offer additional services, such as recycling and reuse programs, and started to replace traditional biocides with green solutions, strengthening its position as a full water-management expert.

As part of that natural maturation—after operators were asking our experts about fracing chemistry— Bosque was working in simple chemicals to determine the best approach to treatment throughout the entire life cycle of the well.

To expand the company’s expertise, it hired Dr. Kenneth Drake as director of technical services to continue tailoring chemistries specifically for the fracing process. Our team was recruited from a wide cross section of the oil industry, including drilling, completions, production, refining, water treatment and logistics.

spwm boyd7Drawing from our experience, we’ve learned that the one-size-fitsall chemistries often cause unforeseen consequences that reduce long-term well production, increase overall costs and even conflict with other chemistries within the chemical program itself.

Bosque develops its own chemical programs through its OptiFluids service line to address issues across each of the major shale plays—including the production issues specific to each basin—as well as reduce costs during and after the fracturing process.

Back to Basics
Before continuing the discussion of the advantages of unbundling frac chemistries, it’s important to outline the basics of what fracing chemicals are meant to achieve and the tests that can be done to evaluate results.

Surfactants are used primarily as a non-emulsifier and flow aid. Common tests to measure effectiveness include surface tension, interfacial tension, emulsion break, contact angle, imbibition and drainage.

Most producers using flow-improvers are only getting approximately 10 to 20 percent of the oil out of the rock. This means there is a great opportunity to get much more.

Testing surfactants on cuttings from the well itself allows us to protect the reservoir’s natural wettability and improve fluid flow, leading to higher flow rates and increased production volumes.

Clay-control products are primarily used for swelling clays, fines control and proppant-embedment control, and there are a handful of tests to measure the success of each. For example, capillary suction time, linear swell and column-drainage tests measure swelling clay control, while roller oven testing remains a primary tool for assessing fines generation.

Proppant embedment tests are a relatively newer tool for evaluating how well proppants are able to maintain fracture width. It is important to note that evaluating products using these features will likely yield significant production gains as there are few remediation options for closed fractures and clogged pore throats.

Historically, swelling clay control was a primary concern for the vertical drilling phase of a well, mostly to maintain wellbore integrity throughout the length of a well. Many of the same tests used to assess these swelling clays were simply translated to the hydraulic fracturing fluid qualification without too much initial thought on the potential mineralogical differences between the overburden and reservoir rocks.

spwm boyd8Friction reducers are used to emulsify, transport and suspend prop placement and enhance recovery by reducing turbulence in the fluid stream. The most commonly used test to measure the effectiveness of a friction reducer is a flow loop test.

This test helps operators and pumping companies ensure fracturing products are being delivered into the reservoir correctly and at a minimal pumping pressure to protect wells and surface equipment.

Product Performance
Bosque recently tested a new claycontrol product in the Niobrara Shale region using a third-party vendor. It outperformed traditional choline chloride by almost two times.

So, what if increased production could be achieved in the fracture network with one chemical instead of several? That’s exactly what this study shows.

The clay-control product tested has the capability to address the variability of the reservoir without disruptions to fluid design or the drilling process. It can prevent clay hydration by the introduction of fresh waters to the stimulated reservoir, prevent fines from dislodging from the rock matrix and preserve the fracture network by slowing proppant embedment.

It is easy to see how significant time and cost can be saved in the lab by efficiently designing the correct testing protocol.

If there are too many or incompatible chemicals going downhole, it could cause an adverse reaction, and production could actually suffer.

Compatibility
It can be tempting to throw everything out to see what sticks, expecting that more chemicals must be better. However, there are times when introducing the wrong combination of chemicals to a reservoir can produce unintended results, just as pharmaceutical drugs may have adverse reactions to your body if taken together.

Never before has there been so many great products to choose from, including modern surfactants and novel biocides—and they may perform well—but when used in the real world, how do they fare?

Basically, if there are too many or incompatible chemicals going downhole, it could cause an adverse reaction, and production could actually suffer. If chemicals don’t work well together, they WILL be more of a hindrance than help.

Although the Niobrara Shale doesn’t typically have issues with clay swelling, it is moderately prone to generating fines with fracturing stress. Roller oven testing and other tests have shown that Bosque’s clay control product—the one used in the thirdparty test mentioned earlier—not only tackles fines generation, but also helps with overall formation stability, which is a potential game changer when trying to increase production from a well.

It is widely known that legacy products like potassium chloride and choline chloride inhibit the hydration of clay minerals. However, the chemical mechanism that allows these products to succeed at controlling clay hydration also changes the structure of the clay mineral.

These changes increase particle dislodgement from the fracture surface and soften the formation face, leading to fines generation and embedment of the proppant into the formation, which can lead to closure of the fracture network and choking of the production channels.

Tailoring fracing programs ensures each chemical used in the process produces the intended result.

spwm boyd9Unbundling Advantage
To summarize, tailoring fracing programs ensures each chemical used in the process produces the intended result.

Never a one-size-fits-all approach, Bosque’s OptiFluids product line offers operators the chemistries and expertise to unbundle frac chemicals for a more customized and consistent approach to increase production, revenue, return on investment and ultimately, shareholder value.

About Bosque Systems
Bosque Systems, an oil and gas water management company, is active in all major oil and gas plays and takes a consultative approach to provide tailored water treatment, reuse, infrastructure and pressure pumping from a suite of experience, in-house customized technologies and chemistries to suit even the worst well conditions.

Always listening to the industry, Bosque adapts to best meet the current need of its operators, helping to increase revenue with cost-effective methods that boost reservoir productivity.

 

 

Authored by Ryan Boyd, vice president of technology, Bosque Systems