Crosslinking of Guar and HPG Based Fracturing Fluids Using ZrO2 Nanoparticles

Abstract

Hydraulic fracturing requires the use of highly viscous gels which are achieved by crosslinking guar gum or its derivatives with boron, zirconium and titanium compounds. Commonly used zirconium complexes contain chelate ligands such as e.g. triethanolamine or lactate. While many different Zr crosslinkers have been developed, their working mechanism has not received much attention. In our study, we focused on the crosslinking of guar and hydroxypropyl guar gum (HPG) with Zr(IV) triethanolamine and lactate complexes. Their interaction with the polysaccharides was studied via particle size measurements, spectroscopic methods and transmission electron microscopy (TEM). It is commonly perceived by the industry that the crosslinking effect of Zr complexes is based on a ligand exchange reaction involving the cis-hydroxyl groups present in guar and HPG. To investigate on this concept, HPG and zirconium lactate were chosen as model system. The polysaccharide and the crosslinker were mixed at low pH where no crosslinking occurred and at higher pH values (> 7) where crosslinking took place. When crosslinking had occurred, IR spectroscopy confirmed that the Zr complexes had hydrolyzed and the lactate ligand had been released suggesting that potentially a ligand exchange reaction had taken place. However, TEM images clearly evidenced the formation of almost monodisperse ZrO2 nanoparticles. Numerous such nanoparticles were found within the gelled HPG. In contrast, when no crosslinking had occurred, almost no ZrO2 nanoparticles could be detected. Based on the observation that the nanoparticles are responsible for the crosslinking of guar, zirconia nanoparticles were synthesized separately and added to guar solutions. Their crosslinking performance was comparable to that of the Zr lactate complex, thus proving that the nanoparticles induce the crosslinking effect. Additional tests revealed that the size of the ZrO2 nanoparticles is a key factor for their crosslinking effectiveness. Particularly small particles (d ~ 3 nm) are most effective while larger particles (d ≥ 10 nm) no longer can crosslink guar.

The gelation of hydroxypropyl guar gum by nano‐ZrO2

“…Because of strong activation performance and small‐sized effect, it is found that Nano‐ZrO 2 can react with HPG through hydrogen bonds and form HPG gel. Based on previous studies, the cross‐linking model of HPG with Nano‐ZrO 2 is proposed (Figure ).…”

Experimental research of stability of emulsion systems with SiO2 nanoparticles

“…На сегодняшний день исследовательские группы по всему миру ве-дут лабораторные тестирования технологических жидкостей с содер-жанием наночастиц различных минералов [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] для их применения в МУН и ИДН. Разработанные технологические жидкости с новыми фи-зико-химическими свойствами должны отвечать следующим основным требованиям: экологичность, селективность и экономическая эффек-тивность.…”

Comparative Studies on Hydraulic Fracturing Fluids for High-Temperature and High-Salt Oil Reservoirs: Synthetic Polymer versus Guar Gum

“…Scheme 1 shows the molecular structure of P3A and guar gum. 25,26 Results suggested that both P3A and guar gum systems exhibit good rheological performance. Nevertheless, many residues of guar gum solutions after gel breaking have impeded the further application.…”

“…Therefore, in this study, for the first time, the rheological performances of P3A solutions were investigated in high-temperature and high-salt conditions and compared with guar gum solutions, whose rheological properties are also absent in the same conditions. Scheme shows the molecular structure of P3A and guar gum. , Results suggested that both P3A and guar gum systems exhibit good rheological performance. Nevertheless, many residues of guar gum solutions after gel breaking have impeded the further application.…”