Synthesis and properties of poly(acrylamide-co-N-vinylpyrrolidone-co-sodium p-styrene sulfonate) as an anionic fluid loss additive

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The P(AM‐co‐AMPS)/SA DN hydrogel was synthesized through aqueous polymerization in this study. It formed a crosslinking network with hydrophobic associations between acrylamide (AM) and lauryl methacrylate (LMA), as well as an ionic bond network involving sodium alginate and Ca2+. To enhance its high‐temperature resistance, 2‐acrylamide‐2‐methylpropane sulfonic acid (AMPS) was incorporated into the hydrogel formulation. The structure of the hydrogel was characterized using Fourier transform infrared spectrometer (FTIR), thermogravimetric analyzer (TGA), and scanning electron microscopy (SEM) techniques. Results demonstrated that the hydrogel exhibited excellent temperature resistance and possessed a porous structure. Mechanical testing revealed a high tensile strength of 110 kPa, elongation at break of 995.31%, along with good fatigue resistance and self‐recovery performance during multiple cyclic stretching. Healing experiments indicated that the healing strength of the hydrogel was influenced by temperature variations. Furthermore, pressure plugging tests were conducted on steel models with crack widths of 0.5 and 1 mm, respectively; it was found that the 0.8%P(AM‐co‐AMPS)/SA DN hydrogel could withstand pressures up to 4.5 MPa at a temperature of 70°C. This novel hydrogel material exhibits remarkable mechanical properties along with certain self‐healing capabilities, making it suitable for leak control applications.

“…The test data encompass apparent viscosity (AV), plastic viscosity (PV), and yield point (YP). 39 The calculation formula is as follows:…”

Section: Api Filtering and Rheological Evaluationmentioning

confidence: 99%

Synthesis and properties of self‐healing hydrogel plugging agent

Bai,

Wang,

Chen

et al. 2023

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Synthesis of novel zwitterionic polymers and their properties as filtrate reducer for water‐based drilling fluid

Bai,

Wu,

Zhang

et al. 2023

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The development of high‐temperature and salt‐resistant filtrate reducer is of great significance to the exploitation of deep and ultra‐deep wells. In this study, Zwitterionic copolymer PANDS was synthesized by free radical polymerization using acrylamide (AM), N‐vinylpyrrolidone (NVP), methacryloxyethyl trimethyl ammonium chloride (DMC) and sodium p‐styrene sulfonate (SSS) as monomers. Through orthogonal test, the optimum synthesis conditions were determined as follows: n (AM): n (NVP): n (SSS): n (DMC) = 3.5:2:0.5:0.5, the reaction temperature is 50°C, the initiator concentration is 0.4 wt%. The structure and thermal stability of the copolymers were analyzed by Fourier transform infrared spectroscopy (FT‐IR), nuclear magnetic resonance spectroscopy (1H‐NMR) and thermogravimetry (TG). In addition, the filtration reduction performance of PANDS was evaluated according to the American Petroleum Institute (API) standard. The mechanism of reducing filtration loss was studied by laser particle size analysis, Zeta potential and scanning electron microscope analysis of mud cake. The results show that PANDS has good temperature resistance and good filtrate loss reduction. With the addition of 1.5%PANDS, the filtrate loss of drilling fluid is 8.7 mL after aging at 160°C for 16 h, and can resist 6 wt% NaCl and 1 wt% CaCl2.

Preparation and performance evaluation of intelligent plugging agent for thermo‐sensitive water‐based drilling fluid

Luo,

Wu,

Yan

et al. 2024

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In the process of unconventional oil and gas exploitation, the invasion of a large amount of drilling fluid into the formation is one of the most critical reasons leading to wellbore instability. A temperature‐sensitive polymer (AOS) was synthesized from acrylamide, oligo (ethylene glycol) methyl ether methacrylate (OEGMA), and sodium p‐styrene sulfonate by emulsion polymerization. The material is a solid‐free fluid with good fluidity at room temperature, after injection into the formation, the fluid is gradually transformed into hard gel above the lower critical solution temperature (LCST) (90°C), thus blocking micro‐fractures and improving wellbore stability. Infrared and NMR characterization confirmed the successful preparation of the target product. The transmittance of AOS with ambient temperature was measured by UV–vis spectrophotometer, and the LCST behavior of AOS was verified by rheological and viscoelastic measurements. The interaction mechanism between AOS and sodium bentonite was evaluated according to the American Petroleum Institute standard. The results show that after aging at 180°C, the filtration loss is reduced by 93%, and the medium permeability (100, 200 mD) formation is effectively plugged, with a plugging efficiency is as high as 74.7%.