Step-by-Step Hydraulic Fracturing Fluid Design (Field Guide)

Hydraulic fracturing fluid design is an engineering process that involves creating a specialized liquid. This liquid is typically made of 99% water with chemical additives and sand to crack underground rock formations and carry proppants that keep the fracture open.

Moreover, the fluid design has modern unconventional shale plays as it focuses on maximizing Stimulated Reservoir Volume (SRV). Due to this, this design has gained a rather positive reputation among completion engineers and technical decision-makers in the oil and gas industry.

The fracturing fluid design may sound simple at first, as it is a combination of water, chemicals and sand to crack underground rocks and keep them open. However, its concept is much wider because of the plethora of concepts involved.

In this guide, we will thoroughly guide you through the hydraulic fracturing fluid design, all the while discussing why the design matters and its regulatory considerations.

Engineering Context: Why Fracturing Fluid Design Matters

The importance of the fracturing fluid shines as it bridges the gap between engineering and geology. Although the design is only a blueprint, it helps to understand the unique rock formations and their challenges. As a result, it ensures that the fracturing process is created and maintained in a controlled way.

Furthermore, the tailored design also assists engineers to effectively optimize low-permeability reservoirs for proppant transport and control fluid loss, all the while preventing damage in the rock formation.

A few decades ago, petroleum-based fluids were used for the fracturing process. Due to the high cost, severe fire and safety hazards, however, the process shifted towards a water-based system.

While a water-based system is much safer, it does not completely exclude all challenges. Under high-temperature and high-stress environments, several hurdles can arise, such as the breakdown of equipment and materials. Due to such hurdles, the operational cost can soar.

Although these hurdles can bring forth a chain reaction of chaos, Sunita USA provides the solution through chemically modified guar derivatives that are combined with specialized crosslinkers and friction reducers.

Step 1 – Define Design Objectives & Constraints

Before you start the chemical selections, you first need to ensure that the objective of the fracturing fluid design is clear. This is because the fluid design can directly influence fluid performance, thereby impacting well productivity, environmental compliance as well as the total project cost.

While on the note of objectives, it should be to maximize the Net Present Value (NPV). You can ensure this by establishing a highly conductive flow path. Through this flow path, you will be able to increase the reservoir’s contact area with the wellbore.

In addition to this, you will also need to ensure that you clearly map the key fluid properties, as we have shared below.

One important factor that you need to comprehend is that the design should directly dictate the fracture geometry and proppant transport. This fundamentally controls long-term hydrocarbon production rate and recovery efficiency.

Step 2 – Gather Critical Reservoir & Water Quality Data

By gathering critical reservoir and water quality data, you will be able to prevent any and all chemical incompatibility, avoid formation damage and optimize fluid viscosity. As a result of this, you will be able to ensure that the fluid is able to pass through rocks and carry materials without running the well.

Aside from this, compatibility testing is another excellent method for gathering critical data. In this testing, fracturing fluids, source water and rocks/fluids are mixed under simulated, well-conditioned circumstances to check whether there is any negative reaction or not. 

This testing helps to comprehend whether there are any mismatches or not. Even a single mismatch in the fluid can result in permanently blocking a well and ruining its production potential.

Different types of water directly dictate polymer hydration kinetics, crosslinking efficiency, and overall additive performance in the fracturing fluid design. To help you better understand this, we have shared a table below of how these substances react to the variety of water.

Step 3 – Select Base Fluid & Core Fluid System

The goal of the fracturing fluid is to create a fracture in the geometry and transport proppants. In order to ensure that the process does not cause the well to close, it is important to select the right base fluids.

According to a study by Oklahoma’s Oil and Natural Gas, the base fluids mainly contain 90-99% water with proppants like sands or ceramics and chemical additives. The water used for fracturing depends entirely on the rock formation, operator, and whether the well is horizontal or vertical. Depending on these factors, the amount of water used per well can be anywhere from about 1.5 million gallons to about 16 million gallons.

Do note that for class II underground injection wells and diesel-based fracking, the EPA (Environmental Protection Agency) regulates fracking fluid disclosure and disposal standards. In addition to this, you will also need to follow the API (American Petroleum Institute), which provides extensive guidelines for both well construction and fluid handling. These regulations aim to prevent groundwater contamination and surface spills.

When selecting the core fluid system, there are five main classes, including slickwater, linear guar, crosslinked guar, hybrids, and foam systems. This is extremely important because fluid viscosity must balance proppant transport and pumping efficiency in hydraulic fracturing. Also, most modern hydraulic fracturing designs prioritize environmental impact and reuse of flowback water.

• Slickwater is used in low-permeability formations to create an extensive surface area.
• In linear guar, water is mixed with uncrosslinked gelling agents like natural guar gum or hydroxypropyl guar (HPG). Linear guar systems are often used in conventional reservoirs as well as the early pad fluid in horizontal completion.
• Crosslinked guar has a composition of crosslinking agents, like boron, zirconium, or titanium metals. This system provides excellent suspension, thereby enabling the transport of high concentrations of large, heavy proppants.
• The composition of hybrid systems combines slickwater pads with crosslinked or linear guar tails. The proppant embedment of hybrid systems can reduce fracture width by 10% to 60%. As a result, it allows for maximizing both fracture length and width and near wellbore conductivity.
• Foam systems have a composition of liquid phase mixed with an energized gas phase. This system has a propagation of time-dependent, compressible and constant-velocity dynamics, giving it exceptional efficiency at bubble yield stress.

Sunita USA provides highly specialized guar-gum derivatives. These derivatives are ideal for fluid fracturing. Moreover, the derivatives can also be engineered to fit the reservoir compatibility through laboratory testing, which is commonly performed to evaluate fluid compatibility with formation minerals.

Step 4 – Design Viscosity Profile & Proppant Transport Strategy

According to a study by Missouri Science and Technology, viscosity controls proppant transport and fracture width at high temperature. However, do note that excessive levels can leave damaging polymer residue, which can impair distribution as well as the final flow capacity. Speaking of proppant transport, a higher fluid viscosity slows down proppant settling velocity. As a result of this, it keeps the solid particles mixed and suspended longer as they travel downwards.

Fracture conductivity, on the other hand, the higher viscosity polymer gels leave the chemical residue inside the proppant pack after the fluids break and flow back. In this step, you will also need to consider the thickness of the fluids. It is difficult for excessively thick fluids to be pumped back out. Therefore, lower viscosity fluids are ideal as they protect conductivity by leaving fewer residues.

In order to design a viscosity profile, balancing proppant transport, fracturing geometry creation, and ensuring fluid loss control against friction pressure will be required. To help you better understand this, we have discussed the different stages of viscosity below.

1. Pad Stage: This is for low-to-moderate initial viscosity as it opens the surface and controls leak-off without excessive friction pressure.
2. Ramp Stage: In this stage, viscosity is stepped or continuously escalating to safely suspend and transport sand/ceramic concentrations.
3. Tail-In Stage: This stage is the final high-concentration proppant phase of the treatment schedule. In this stage, a specialized high-viscosity slug is required to manage maximum solid loading. Though, do ensure that your materials have high resistance to corrosive environments.

Step 5 – Select and Optimize Fracturing Fluid Additives

In the hydraulic fracturing process, matching chemical properties to reservoir parameters, focusing on friction reducers, crosslinkers, breakers, surfactants, clay stabilizers, biocides, scale inhibitors and corrosion inhibitors. In this, the core performance is entirely dependent on the temperature limits, water compatibility, and shear stability.

• Friction Reducers: These are long-chain polymers that minimize turbulent drag pressure during high-rate slickwater pumping.
• Crosslinkers: These metal complexes lock the polymer chain to sustain high-temperature viscosity and ensure fluid flow.
• Breakers: These oxidizes or enzymes degrade the gel post-treatment to protect fracture conductivity. Moreover, they liquify the liquid to ensure complete clean-up without leaving residue that plugs the rock pores.
• Surfactants: These surface-active agents lower the tension between the fracturing fluid and reservoir rocks. As a result, surfactants improve fluid penetration into rock pores.
• Clay Stabilizers: Also often referred to as formation protectors, clay stabilizers include chemical salts (KCI) or choline chloride and safeguard the natural permeability of the reservoir against water-induced damage.
• Biocides: These are fast-acting antimicrobials that kill downhole sulfate-reducing bacteria.
• Scale Inhibitors: These inhibitors block minerals like calcium carbonate from precipitating out of solution. As a result, they shield the metal from the flow-restricting crust from fluid injection.
• Corrosion Inhibitors: These inhibitors include an amine-based compound that forms a protective molecular film over the steel wellbore casing. Due to this, it effectively shields the metal from acidic fluids and dissolved oxygen degradation during high-pressure pumping in oil and gas wells. 

Fracture height, width, and length are crucial for optimization. Moreover, Fracture azimuth determines optimal well placement in tight formations. From crosslinkers to surfactants, Sunita USA offers a comprehensive range of fracturing fluid products that ensure complete optimization.

Step 6 – Model, Pilot, and Iterate the Fracturing Fluid Design

Modeling, piloting, and iterating are all continuous optimization process that aims to maximize well production while minimizing formation damage along with operational cost. Below, we have thoroughly explained them to help you understand what they are, how they work, and their importance in the fracturing fluid design.

• Modeling: This process involves gathering data on temperature, mineralogy, permeability, and closure stress to define the properties of the reservoir. Through this, you can check clay swelling or scale formation and evaluate the damage potential.
• Piloting: This process runs break tests, rheology profiles and fluid-loss control measurements to check fluid composition. In this process, the fluid is pumped through the actual reservoir core samples to measure permeability recovery. Moreover, you can also use the leak-off data to calibrate and update your initial model.
• Iterating: Proactively track treating pressures, rate changes and blender performance. Moreover, you will also need to analyze and optimize flowback water chemistry and breaker schedules, friction reducers, or crosslinker concentrations. You can later use this data as a new baseline for the asset.

Step 7 – Optimization, Cost–Performance Tradeoffs, and Custom Formulation

Hydraulic fracturing fluid design requires balancing high conductivity with low fluid cost and minimal formation damage. Therefore, you must consider these factors when optimizing the chemistry of the fracturing fluid design. The tradeoff of not considering these factors can be rather dire, as they may directly impact the performance of the fracturing fluid.

In order to avoid the cost of soaring, you must ensure that there are no stones left unturned in your custom formulation. For this, you can choose Sunita USA for complete custom formulations and blending services.

Environmental, Safety, and Regulatory Considerations in Fluid Design

Hydraulic fracturing fluid designs are required to manage groundwater protection, chemical toxicity, and surface safety through strict adherence to water management, casing integrity standards, and chemical disclosure laws. These laws aim to prevent any and all hydrocarbon flow in the environment from the target rock formation.

In order to adhere to environmental, safety, and regulatory compliance, the use of lower-toxicity, biodegradable additives and dry powder forms is ideal. This shift reduces environmental liabilities, all the while improving workers’ safety and simplifying site logistics.

Sunite USA accelerates compliance and environmental stewardship through custom green formulations. By engineering biodegradable additives and dust-free dry powders, we minimize toxicity and simplify FracFocus reporting. This proactive approach ensures absolute aquifer protection, reduces logistical hazards, and secures seamless regulatory approvals.

Why Partner with Sunita USA Inc. for Fracturing Fluid Design

In the industry of oilfield chemistry, Sunity USA is a highly renowned name. With deep experience in fracturing fluids and acid gelling agents, we were also recognized as the best chemical company of 2022 in El Reno, Oklahoma. From guar gum polymers to friction reducers, we offer the highest quality products to fulfill your hydraulic fracturing requirements.

Contact us today and create your hydraulic fracturing fluid design with state-of-the-art quality products

Shivam Vaajpayi