HE^® or "Hostile Environment" polymers 100 and 300 are a family of synthetic, water soluble polymers of varying composition and molecular weight developed for high-temperature oilfield applications. These polymers are generally available as either powders or invert emulsion.

HE^® Polymer 100 Emulsion is an efficient thickener for a wide variety of fluid types, including fresh water, seawater, brines and acids.  It is an invert (oil-outside phase) emulsion, with the polymer contained in the water phase. 

Advantages of HE^® Polymer 100 Emulsion

• Hydrates rapidly in most aqueous systems
• Resists thermally induced hydrolysis
• Maintains solubility at high temperatures
• Provides excellent friction reduction
• Thickens brines of various compositions
• Improves carrying capacity of fluids
• Crosslinkable with transition metal ions or organics
• High tolerance to changes in pH 

Invert Emulsion: Clear to opaque liquid, this emulsion contains 2.6 lbs of HE^® 100 polymer in each gallon, or 309 kg/m³.

The emulsion polymer is available in 55-gallon drums.

Useful as a thickener or friction reducer in the following brines, or mixtures:

· Fresh Water
· Seawater
· Potassium Chloride
· Potassium Bromide
· Sodium Chloride
· Sodium Chloride – Sodium Carbonate
· Sodium Bromide
· Alkali Metal Formates
· Calcium Chloride
· Calcium Bromide (up to 250º F)

Applications

HE^® Polymer 100 Emulsion has historically been used in a wide variety of oilfield applications.  Because of its excellent friction reduction capabilities, it has been widely used in coiled tubing workover operations and in fracture acidizing.

In conformance control applications, the HE^® Polymer 100 provides flexibility in treatment design and superior high temperature stability. At low to intermediate temperatures, it can be readily crosslinked with chromium, aluminum and zirconium ions to produce gels for profile modification or water shutoff. At high temperatures, it can be readily crosslinked with various organic systems, including phenol-formaldehyde, resorcinol-formaldehyde, phenyl acetate-HMTA or hydroquinone-HMTA.

The HE^® Polymer 100 has been utilized as a thickener for brines in drilling and completions applications. The HE^® Polymer 100 Emulsion is readily inverted in most brines, with moderate shear, yielding rheological properties similar to that shown in Figure 1, which describes the polymer’s performance in a 10.7 ppg calcium chloride brine at 70°F.

In the very light brines, such as 1% KCl, efficient inversion of the emulsion may require the addition of a small amount of demulsifying surfactant.

Stability

The composition of the HE^® Polymer 100 provides protection against thermal hydrolysis, which allows the polymer to maintain its solubility in high temperature use and to resist precipitation in the presence of multivalent cations. In this Fann 50 test (Figure 2), the thickened calcium chloride brine was heated incrementally to 300º F. The fluid was kept at each temperature for one hour before proceeding to the next stage. There was very little change in viscosity during that one-hour period, which demonstrates the polymer stability at high temperatures. Almost all of the original viscosity was regained upon cool-down, again indicating no polymer degradation, hydrolysis or loss due to precipitation. In most high temperature brine applications, the polymer may benefit from the use of oxygen scavengers (e.g., sodium thiosulfate) and pH buffers (e.g., sodium bicarbonate)

Polymer Cleanup

The HE^® Polymer 100 Emulsion is an inherently clean thickener, posing very little risk of formation damage under normal usage conditions. The HE^® Polymer 100 is readily soluble in normal wellbore cleanup type acids. The polymer is degradable using oxidizing agents, such as sodium hypochlorite (bleach) or ammonium persulfate. The activity of the oxidizer is generally enhanced by using fluid with a basic pH. Degradation by oxidizers is also enhanced at temperatures above 125º F.