Synthesis and Characterization of Sodium Carboxymethyl Starch‐Graft Acrylamide/1‐Vinyl‐2‐Pyrrolidone Copolymers via Central Composite Design and Using as Filtration Loss Agent in Drilling Muds

Abstract

A graft copolymer is synthesized with graft copolymerization of acrylamide (AM) and 1‐vinyl‐2‐pyrrolidone (NVP) grafting onto sodium carboxymethyl starch (CMS) via central composite design (CCD). The initiation system consists of potassium persulfate (KPS) and sodium hydrogen sulfite (SBS). The copolymer is confirmed by infrared spectroscopy, nuclear magnetic resonance hydrogen spectroscopy, scanning electron microscopy, thermogravimetric experiment, and elemental analysis. The rheological performance, filtration loss, cake thickness, and cake fictional coefficient of the drilling mud containing copolymer are evaluated. The results show that copolymers have ability to thicken and reduce filtration volume and have no obvious influence on the thickness and fictional coefficient of the mud cake. Response surface methodology (RSM) is exerted for variable evaluation and optimization. The results indicate that initiator concentration is the main contributing factor to decrease filtration volume and the optimum results are 1.5 wt% (initiator concentration), 1.82 (mole ratio of monomer to starch [AGU]), 66.02 °C (reaction temperature), 3.87 h (reaction time). The predicted value and the actual experimental value are 8.64 and 9 mL respectively with an error of 4.01%. The small error indicates that there is a small deviation between the actual and the predicted values, which also shows that the model is reasonable.

Study of a novel cross linked graft copolymer starch in water-based drilling fluid

“…The FT-IR spectrum analysis of the SAANM is presented in figure 2. The spectrum exhibited characteristic absorption peaks of the -OH group in the main chain of the starch and the stretching vibrations of N-H in amide groups at 3327 cm −1 [49]. Additionally, the peak at 2930 cm −1 corresponded to the characteristic vibration absorption peak of C-H on the backbone of the polymer molecule, and 1016 cm −1 was attributed to the asymmetric stretching vibration of C-O-C in starch [49].…”

Effective Modified Xanthan Gum Fluid Loss Agent for High-Temperature Water-Based Drilling Fluid and the Filtration Control Mechanism

“…Results show that the product has the most excellent performance in reducing filtration volume, and the rheological performance is similar to that of CMS and better than CMC-LVT. 21 A graft copolymer KH570-AM-starch is synthesized by cassava starch (CSt), AM, and γ-methacryloxypropyl trimethoxysilane (KH570) that can be used as a fluid loss agent at 140 °C. 28 It is worth noting that KH570-AM-starch must be compounded with other agents to achieve a temperature resistance of 180 °C.…”

“…Numerous studies have shown that modification is an effective method to improve or obtain polymers. − Some modified polymers have been used as high-performance treatment agents. − For instance, Xiaodong Bai et al. graft acrylamide (AM) and 1-vinyl-2-pyrrolidone (NVP) onto sodium carboxymethyl starch (CMS).…”

“…graft acrylamide (AM) and 1-vinyl-2-pyrrolidone (NVP) onto sodium carboxymethyl starch (CMS). Results show that the product has the most excellent performance in reducing filtration volume, and the rheological performance is similar to that of CMS and better than CMC-LVT . A graft copolymer KH570-AM-starch is synthesized by cassava starch (CSt), AM, and γ-methacryloxypropyl trimethoxysilane (KH570) that can be used as a fluid loss agent at 140 °C .…”

Experimental Study of Bentonite-Free Water Based Mud Reinforced with Carboxymethylated Tapioca Starch: Rheological Modeling and Optimization Using Response Surface Methodology (RSM)

“…The modification could affect the crystallinity, morphology, thermal stability, and hydrophobicity of the starch. Therefore, physical, chemical, enzymatic, or dual modifications are the promising approaches for developing new products, retaining petrochemical resources and enhancing specific starch properties [ 12 ]. Chemical modification is the most widely accepted approach and contributes to the emergence of new functionality to the starch.…”