A Crosslinkable Synthetic-Polymer System for High-Temperature Hydraulic-Fracturing Applications

Abstract

Summary A new hydraulic-fracturing fluid has been developed that is capable of reaching fluid service temperatures up to 232°C. This fracturing fluid technology uses a synthetic polymer that is crosslinkable with metal ions to generate high viscosity. The synthetic-polymeric fracturing gel overcomes the thermal limitations of traditional guar and derivatized guar-based fracturing fluids. Several advancements have been made in the development of this technology to maximize the efficiency of crosslinking and to give an effective breaking profile, resulting in good laboratory gel cleanup in the proppant pack. Research efforts have yielded a fracturing fluid with good fluid stability at high temperatures to create better proppant transport and placement in these most-demanding environments. An integral part of this fluid is a crosslinking system that can be "tuned" for crosslinking onset from 38 to 138°C, allowing for optimization for particular well conditions. The crosslinking system allows the treatment schedule to be tailored to the targeted well to help minimize frictional pressure loss. An efficient and effective oxidative-breaker package has been developed to give a controlled rheological break for the synthetic fluid and provide good regained conductivity data. The new, high-temperature fracturing technology provides a new tool to stimulate hotter, deeper hydrocarbon resources to help maximize hydrocarbon recovery. This fracturing-fluid system has been applied successfully in south Texas at temperatures approaching 232°C. Laboratory rheological data that demonstrate fluid stability, crosslinking performance, and controlled fluid breaks are presented. Dynamic fluid-loss and regained-conductivity data are also presented to illustrate fluid cleanup in proppant packs.

Impact of salts on polyacrylamide hydrolysis and gelation: New insights

“…These processes comprise drilling, polymer flooding and other enhanced oil recovery methods, such as alkaline and alkaline–surfactant–polymer (ASP) flooding. In improved oil recovery, PAM is used in water control, friction reduction, and more recently as a fracturing fluid . PAM can be crosslinked with different types of crosslinkers to produce polymeric gels for water control in conformance improvement treatments.…”

“…In improved oil recovery, PAM is used in water control, 1 friction reduction, 2 and more recently as a fracturing fluid. 3 PAM can be crosslinked with different types of crosslinkers to produce polymeric gels for water control in conformance improvement treatments. These include inorganic crosslinkers such as chromium [4][5][6][7][8] and organic crosslinkers such as phenol and formaldehyde 9 or polyethylenimine (PEI).…”

Preparation of a novel fracturing fluid with good heat and shear resistance

“…Moreover, synthetic polymers have the advantages of strong thickening ability, good gel stability, strong ability to carry sand, insensitivity to bacteria, less residue formation, and low damage to reservoirs. [15][16][17][18] Nevertheless, polymer-based fracturing uids are unstable at high temperatures and high shear rates. In addition, the water solubility of synthetic polymers is poor compared to viscoelastic surfactants.…”

Application of a Zwitterionic Hydrophobic Associating Polymer with High Salt and Heat Tolerance in Brine-Based Fracturing Fluid

“…Water-soluble macromolecular polymers, such as guar gum and acrylamide polymers, have been widely applied as thickeners in fracturing fluids [4]. However, conventional guar gum and acrylamide polymers can cause serious damage to the formation by blocking the pore throat and have poor salt-tolerance and temperature-tolerance [5,6]. In the process of oil and gas field development, the reservoir temperature and salinity become higher with the increase of reservoir heterogeneity.…”