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US crude oil production is expected to continue rising in the face of recent events, including the resurgence of travel and the emergence of global conflicts that have led to less oil availability in the market. In the United States, over one million oil and gas wells have been completed using hydraulic fracturing, or fracking, since the 1940s. |
To this day, fracking remains a significant fixture in economic output and environmental concerns within the oil and gas industry. For this reason, optimizing the efficiency and productivity of the fracking and recovery processes is important. Tyzor® organic titanate and zirconate cross-linkers are instrumental tools that oil well service companies can use to improve these processes.
Tyzor® Organic Titanates and Zirconates
Dorf Ketal’s Tyzor® organic titanate and zirconate cross-linkers have been used for decades to increase the productivity of oil and gas wells. They are ideal for cross-linking drilling and fracturing fluids and are offered for solvent-based, solvent-free, and water-based applications. A variety of Tyzor® grades are available to provide cross-linking at various rates, pH, and temperatures, allowing oil well servicers the necessary customization to build viscosity based on the specific conditions of each well.
Most Tyzor® products used in oil and gas applications are stable chelates of zirconium that provide cross-linking of functionalized polymers containing hydroxyl and carboxyl groups by the following mechanism:
As most gelling agents used in oil and gas well production, such as guar, guar derivates, cellulosic polymers, and synthetic polymers, are functionalized polymers with hydroxyl and carboxyl group functionality, Tyzor® grades serve as effective cross-linking agents that increase polymer molecular weight and build viscosity for drilling and fracturing fluid applications. The mechanism and specific benefits of Tyzor® in these applications are explored in further detail below.
Tyzor® Titanates and Zirconates for Fracturing Fluids
The main purpose of building viscosity in fracturing fluids is to allow better delivery of the proppant into the fissures created to access tight oil reserves. These fissures, which are under high pressure, are “propped” open by the proppant so that crude oil and gas can escape into the well. The natural tendency of the proppant is to settle in the fracturing fluid since it is typically a low-viscosity liquid and proppant is typically an assortment of particles that are roughly the size and shape of sand. This causes fewer proppants to enter fissures, reducing access to the oil or gas reserve. When fracturing fluids are more viscous, proppants are suspended better and can enter fissures more effectively.
Customization with Tyzor®
Several Tyzor® grades are available for use in fracturing fluids to provide utility in varying treatment conditions. When selecting a grade, consider the conditions, such as the gelling polymer type, concentration, well temperature, brine type and strength, pH, breaker system, target viscosity, and desired cross-linking rate. The most common options used in this application are shown below.
| Grade |
Type |
ZrO2 or TiO2 Content (%) |
Description |
Application Notes |
| Tyzor® 212 |
Zirconium Chelate |
12.4 |
Zirconium chelate delayed cross-linker in alcohol for guar derivatives. Triethanolamine free. Forms high-viscosity gels at up to 162.8°C. |
Cross-linking initiates after 4 minutes at approximately 49°C in CMHPG-based fluids at pH 8.5–10. Effective in low-pH (4–5) applications up to 93.3°C. |
| Tyzor® 217 |
Zirconium Chelate |
5.4 |
Aqueous zirconium chelate delayed cross-linker for guar derivatives. Forms high-viscosity aqueous gels at up to 121.1°C. |
Cross-linking initiates after 3 minutes at approximately 27°C in CMHPG-based fluids at pH 8.5–10. |
| Tyzor® TE |
Titanium Chelate |
13.7 |
Triethanolamine titanium complex cross-linker for natural guar and HPG at up to 135°C. |
Initiates cross-linking after 30 seconds at approximately 27°C in HPG-based and natural guar-based fluids at pH 7. |
Other grades, such as Tyzor®
TEAZ,
CLA, and
AA-75, may also be used in this application. With this assortment of options, oil well servicers have the flexibility to customize and calculate gel time to each well’s needs.
Tyzor® for Modern Gelling Agents
Typically, guar derivate polymers, such as hydroxypropyl guar (HPG), carboxymethyl guar (CMG), or carboxymethyl hydroxypropyl guar (CMHPG), have been used in fracturing fluids as gelling agents along with Tyzor® to build viscosity. Recently, the usage of guar polymers has declined due to cost concerns in favor of synthetic polymers, such as polyacrylamides (PAMs), which increase viscosity at lower prices. As detailed previously, Tyzor® is an excellent cross-linking agent in a wide variety of polymers, including synthetic polymers, which cost less. Therefore, Tyzor® is ideal for servicers looking to improve oil and gas recovery while using less costly synthetic polymers.
Tyzor® versus Borate Cross-linkers
One of the major environmental concerns surrounding the oil extraction process is produced water. This waste product contains hydrocarbons, heavy metals, and high concentrations of total dissolved solids (TDS) and is extremely challenging to treat. When fracturing fluids are formulated, significant amounts of fresh water are used, creating challenges around cost and environmental friendliness. Recently, scientists and engineers have proposed using produced water or seawater to replace fresh water in fracturing fluids.
Tyzor® can provide significant benefits in this use case due to its performance in high-TDS fluids, as metal cross-linkers like Tyzor® have successfully created fracturing fluids in TDS levels as high as 280,000 mg/L. Other commonly used cross-linkers, such as relatively inexpensive borates, have only been shown to effectively cross-link at TDS levels less than half of what metal cross-linkers achieve. Thus, Tyzor® can provide a major advantage over borate cross-linkers in terms of cost and conservation of fresh water.
Tyzor® Titanates and Zirconates for Drilling Fluids
Tyzor® cross-linkers are useful in drilling fluids to form materials that function as fluid-loss additives. Tyzor® can cross-link fatty acids, such as oleic or stearic acids; metal oxides; and polymers used to thicken drilling fluids to ensure minimal loss of drilling fluids to permeable formations present when drilling a well. This is also a significant feature to help mitigate environmental contamination. For stabilization and protection against inorganic salts, Tyzor® can cross-link anionic emulsifiers, such as calcium dodecyl benzene sulfonate.
Summary
As oil and gas production in the United States continues to rise, Tyzor® titanate and zirconate cross-linkers are instrumental in optimizing the efficiency of oil well drilling and completions. Various Tyzor® grades have been developed to provide oil well servicers the flexibility to build viscosity in fracturing fluids with the necessary time delay based on the well’s operating conditions.
Tyzor® can cross-link several types of polymers used for gelling, ranging from traditional carboxymethyl hydroxypropyl guar to recently more common synthetic polymers, such as polyacrylamides. Tyzor® metal-based cross-linkers also perform better in high-TDS solutions than other cross-linkers like borates. Thus, Tyzor® can enable the use of produced water or seawater in place of fresh water to formulate fracturing fluids. In drilling fluids, Tyzor® also helps form fluid-loss additives that reduce permeation to surrounding formations.
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