Nano-Enhanced Elastomers for Oilfield Applications

Abstract

The use of elastomers in oil industry extends over a broad range of applications including seals, packing elements, reactive rubber elements, stators, and pads. These applications require a variety of property requirements that may differ for dynamic and static applications or include a need for stimuli-responsive capabilities in certain tools. This research details the effect of nanofillers on elastomer properties for oil and gas components. The effects include enhancement of mechanical properties, wear resistance, thermal conductivity and heat expansion properties. In addition, effects of nanofillers on rapid gas decompression (RGD) resistance, chemical resistance to downhole fluids, and resistance to chemical aging at downhole temperatures were investigated. Advanced rubber nanocomposites formulations, based on Hydrogenated Nitrile Butadiene Rubber (HNBR) elastomers, were designed internally. Their properties were assessed using methods and techniques to qualify elastomers for downhole applications. Mechanical properties of elastomers were evaluated at room temperature and at 325° F, which is a maximum application temperature for HNBR elastomers. RGD testing was conducted according to ISO standards. Results indicated that it is possible to control mechanical properties of elastomers with nanotechnology, including improving the abrasion resistance of the elastomers by more than 100% in dynamic, wear-intensive applications, when compared to commercial compounds typically used in the oil industry. Thermal conductivity was improved by up to 40%, while heat expansion decreased by 30%, providing more versatility for seal design in dynamic applications which are prone to localized heating. In addition, RGD resistance in nanocomposites was examined and compared it to control samples. The industrial scale feasibility for nano-enhanced elastomers was demonstrated by a scale-up study.

Effect of Engineered Nanoparticles on Enhancement of Composite Properties Relevant to Oilfield Applications

“…As the result, it was found that CNTs enable a superior wear resistance. 15,16 The HNBR reinforcement with as little as 15 phr of CNTs provided better resistance to wear than 50 phr of N234 carbon black. The difference in performance was even more drastic when compared with 50 phr of generalpurpose carbon black grades N550 and N326 (Figure 2).…”

“…Polymer chains of HNBR and XHNBR were cross-linked through reactions with peroxide, whereas carboxyl groups of XHNBR and functionalized CNTs were cross-linked by metal ions, e.g., Zn 2+ or Zr 4+ originating from zinc oxide and zirconium(IV) tert-butoxide, respectively, added to the mix. 19,20 The proposed schematics of the cross-linking reaction mechanism ultimately leading to the formation of hybrid elastomer nanocomposites suitable for high-temperature applications are shown on Figure 5.…”

“…It was also found that the elastomer nanocomposite sample C cross-linked with the zirconium tertbutoxide has further enhanced modulus and tensile properties with respect to sample B, which has been cross-linked with zinc oxide and composed of higher content of CNTs. 19 This is most likely due to the occurrence of more efficient cross-linking reaction of carboxylate groups at XHNBR and CNTs through Zr 4+ than Zn 2+ cations and resulting in a higher density of crosslinks, in accordance with the much higher coordination number of zirconium.…”

“…The key issues in elastomer nanocomposite formulations are the degree of nanoparticle dispersion within the polymer matrix and availability of the load transfer mechanism at the interface between blend components. Different reaction schemes of incorporating nanoparticles into the polymer matrix and various nanofiller surface functionalizations were considered. , A custom peroxide-cured HNBR formulation, commonly used in oilfield applications, was selected as a base recipe for this research. Furthermore, our goal was to test the hypothesis that a combination of fillers of different sizes and structures, e.g., carbon black (CB) and CNTs, can create a synergistic effect, enabling significant improvements in matrix reinforcement and helping balance the relatively high cost of CNTs compared to carbon black.…”

Click Reaction Functionalization of Hydroxylated Nanoparticles by Cyclic Azasilanes for Colloidal Stability in Oilfield Applications

“…Colloidal systems of functionalized nanoparticles have been evaluated in oil industry for enhanced oil recovery, formation damage remediation, flow assurance, and water treatment operations [1]- [8]. Surface modified nanoparticles have also been considered for applications as tracers in reservoir studies, active media in thermal management fluids, and fillers in high performance elastomers [9] [10] [11] [12] [13]. Conventional functionalization of nanoparticles, which mostly use alkoxysilanes and chlorosilanes for covalent bonding to surface, need catalytic amount of water for the reactions to proceed, require multiple hours to fully saturate the surface, and release by-products capable of interfering with the desired functional or chemical behavior of the modified surface [14].…”