RESUMEN
The application of cellulose derivatives including carboxymethyl cellulose (CMC), polyanionic cellulose (PAC), hydroxyethyl cellulose (HEC), cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) has gained enormous interest, especially as environmentally friendly additives for water-based drilling fluids (WBDFs). This is due to their sustainable, biodegradable, and biocompatible nature. Furthermore, cellulose nanomaterials (CNMs), which include both CNFs and CNCs, possess unique properties such as nanoscale dimensions, a large surface area, as well as unique mechanical, thermal, and rheological performance that makes them stand out as compared to other additives used in WBDFs. The high surface hydration capacity, strong interaction with bentonite, and the presence of a complex network within the structure of CNMs enable them to act as efficient rheological modifiers in WBDFs. Moreover, the nano-size dimension and facilely tunable surface chemistry of CNMs make them suitable as effective fluid loss reducers as well as shale inhibitors as they have the ability to penetrate, absorb, and plug the nanopores within the exposed formation and prevent further penetration of water into the formation. This review provides an overview of recent progress in the application of cellulose derivatives, including CMC, PAC, HEC, CNFs, and CNCs, as additives in WBDFs. It begins with a discussion of the structure and synthesis of cellulose derivatives, followed by their specific application as rheological, fluid loss reducer, and shale inhibition additives in WBDFs. Finally, the challenges and future perspectives are outlined to guide further research and development in the effective utilization of cellulose derivatives as additives in WBDFs.
RESUMEN
Shale hydration dispersion and swelling are primary causes of wellbore instability in oil and gas reservoir exploration. In this study, inulin, a fructo-oligosaccharide extracted from Jerusalem artichoke roots, was modified by acylation with three acyl chlorides, and the products (C10-, C12-, and C14-inulin) were investigated for their use as novel shale hydration inhibitors. The inhibition properties were evaluated through the shale cuttings hot-rolling dispersion test, the sodium-based bentonite hydration test, and capillary suction. The three acylated inulins exhibited superb hydration-inhibiting performance at low concentrations, compared to the commonly used inhibitors of KCl and poly (ester amine). An inhibition mechanism was proposed based on surface tension measurements, contact angle measurements, Fourier-transform infrared analysis, and scanning electron microscopy. The acylated inulin reduced the water surface tension significantly, thus, retarding the invasion of water into the shale formation. Then, the acylated inulin was adsorbed onto the shale surface by hydrogen bonding to form a compact, sealed, hydrophobic membrane. Furthermore, the acylated inulins are non-toxic and biodegradable, which meet the increasingly stringent environmental regulations in this field. This method might provide a new avenue for developing high-performance and ecofriendly shale hydration inhibitors.
RESUMEN
Hydrogel actuators with anisotropic structures exhibit reversible responsiveness upon the trigger of various external stimuli, rendering them promising for applications in many fields including artificial muscles and soft robotics. However, their effective operation across multiple environments remains a persistent challenge, even for widely studied thermo-responsive polymers like poly(N-isopropyl acrylamide) (PNIPAm). Current attempts to address this issue are hindered by complex synthetic procedures or specific substrates. This study introduces a straightforward methodology to grow a thin, dense PNIPAm nanoparticle layer on diverse hydrogel surfaces, creating a highly temperature-sensitive hydrogel actuator. This actuator demonstrates adaptability across various environments, including water, oil, and open air, owing to its distinct structure facilitating self-water circulation during actuation. The thin PNIPAm layer consists of interconnected PNIPAm nanoparticles synthesized via in situ interfacial precipitation polymerization, seamlessly bonded to the hydrogel substrate through an interfacial layer containing hybrid hydrogel/PNIPAm nanoparticles. This unique anisotropic structure ensures exceptional structural stability without interfacial delamination, even enduring harsh treatments such as freezing, ultrasonic irradiation, and prolonged water immersion. Remarkably, PNIPAm films on hydrogel surfaces which enable programmable 3D actuation can also be precisely patterned. This synthetic approach opens a novel pathway for fabricating advanced hydrogel actuators with broad-ranging applications.
