Preparation of High Temperature Resistant High Strength Supramolecular Gels Based on Hydrophobic Association and Hydrogen Bonding and its Application in Formation Pluggingg

Abstract

The traditional chemical cross-linking method is based on the formation of covalent bonds between molecules to connect three-dimensional networks to enhance the strength of hydrogels. Although this method can significantly improve the mechanical properties, it also has many problems, such as irreversibility and fatigue. Therefore, the design and preparation of supramolecular hydrogels with high mechanical properties and good temperature resistance have very important research significance and practical value. This paper prepared a supramolecular gel with both temperature resistance and mechanical properties through hydrophobic association and hydrogen bonding, and evaluated its thermal stability, rheology, temperature resistance and pressure plugging ability. The results showed that the supramolecular gel had excellent thermal stability, and there was strong physical entanglement between its three-dimensional network structures, which made it difficult to be destroyed by increasing temperature. The excellent rheological properties of supramolecular gels enable them to maintain good viscoelastic changes in the linear viscoelastic region within the strain range of 0.1-30%. When the strain was greater than 30%, the supramolecular gel began to undergo different degrees of sol-gel phase transition, which showed that the energy storage modulus of supramolecular gel decreased. In addition, the energy storage modulus of supramolecular gel was always greater than the loss modulus in the whole frequency scanning range, and there was no intersection between the two gel and the gel always showed high elasticity. Meanwhile, the supramolecular gel still had good structure and strength after high temperature aging. Its tensile and compressive properties did not change significantly, but the color of the gel surface changed slightly, which could maintain good structural stability under high temperature environment. Supramolecular gel particles could be used as plugging materials for drilling fluid, and had excellent plugging ability of formation fractures and pores. The plugging ability of 1mm aperture plate model was up to 6.3MPa, and the plugging ability of 1mm seam width was up to 4.9MPa. Therefore, the development and application of supramolecular gel plays an important supporting role in drilling fluid plugging.

Multiple Hydrogen Bonding-Assisted High-Strength Hydrogel of Silica/Polyacrylamide Nanocomposite Cross-Linked with Polyethylenimine

“…Besides, another problem that gel can address is lost circulation (LC), which is a common issue during drilling operations . Lost circulation is prone to happen in formations including pore throats, induced or natural fractures, and caverns . Events such as a blowout may take place in severe situations.…”

“…14 Lost circulation is prone to happen in formations including pore throats, induced or natural fractures, and caverns. 15 Events such as a blowout may take place in severe situations. Cross-linked polymers can seal a large scale of pore space or fracture and offer an efficient solution to deal with severe lost circulation events.…”