Controlling Shale Swelling and Fluid Loss Properties of Water-Based Drilling Mud via Ultrasonic Impregnated SWCNTs/PVP Nanocomposites

Abstract

Wellbore instability due to shale swelling and fluid loss of drilling mud is the main challenge faced by the oil and gas industry. Herein, we successfully demonstrated the positive impact of newly developed single-walled carbon nanotubes/ polyvinylpyrrolidone (SWCNTs/PVP) nanocomposites on the drilling efficiency of water-based muds (WBMs). By adopting a standardized sonication technique, we achieved highly dispersed and uniform distribution of single-walled carbon nanotubes (SWCNTs) within the matrix of polyvinylpyrrolidone (PVP). SWCNTs provided the required mechanical strength and hydrophobicity, while PVP acted as a binder, filler, and dispersion medium. The surface morphology of shales was compared before and after modification with SWCNTs/PVP nanocomposites. The moisture adsorption/repellent characteristics of the shales were predicted by Fourier transform infrared (FTIR) spectroscopy. The dispersion stability of synthesized SWCNTs/PVP nanocomposite with bentonite clay in the presence of water was also recorded for 24 h. The drilling mud modified with 5-SWCNTs/PVP nanocomposite demonstrates 23% reduction in fluid loss. The inhibition stability and swelling rate of shales were systematically investigated and compared with water, KCl, unmodified mud, and commercial shale inhibitor. The comparison indicates that the modified drilling mud having 5-SWCNTs/PVP composite showed the highest dispersion recovery (89.5%) and the lowest swelling rate (21.6%). The synthesized nanocomposite not only forms a protective layer on the shale surface to hinder the access of water but also offers structural stability to the drilling mud. Improved swelling inhibition, fluid loss control, and long-term stability of shale against reactive fluid, suggested that the modified WBM can be effectively utilized to control wellbore instability during drilling operations.

Advances in Carbon Nanostructures and Nanocellulose as Additives for Efficient Drilling Fluids: Trends and Future Perspective—A Review

“…The highly stable dispersion of SWCNTs/PVP enhanced the shale dispersion recovery up to 89.5% and the swelling rate dropped down to 21.6%. Additionally, a prominent drop in the filtration loss was observed due to nanopores plugging and the hydrophobic nature of the nanocomposite …”

“…Additionally, a prominent drop in the filtration loss was observed due to nanopores plugging and the hydrophobic nature of the nanocomposite. 124 Borehole stability, as well as rheological and filtration characteristics, of the drilling mud systems should be tuned properly for HTHP drilling operations to achieve reasonable recovery on an industrial scale. As mentioned earlier, CNTfilled polymers could be an excellent substitute for this purpose.…”

Experimental investigation of a low-molecular-weight polymer coating agent for deep-sea oil and gas drilling

“…The shale expansion experiment is used to analyse the hydration swelling property of shale samples in drilling fluids. The shale expansion experiments were conducted using a NP-2 expansion instrument to test the variations of the height of the shale sample to determine its linear expansion rate after immersed in pure water and coating agent solutions (Rana et al 2020). Bentonite which was crushed and sifted through a 100-mesh screen, was used to prepare the core sample.…”

Experimental Study on the Polymer/Graphene Oxide Composite as a Fluid Loss Agent for Water-Based Drilling Fluids

“… 38 The single-walled carbon nanotubes/poly(vinylpyrrolidone) (SWCNTs/PVP) nanocomposites developed by Rana et al can significantly improve the instability of shales. 39 The polypropylene–silica nanocomposite (PP–SiO 2 NC) studied by Oseh et al is superior to partially hydrolyzed polyacrylamide in terms of controlling rheology and fluid loss. 40 It can be seen that polymer/nanocomposites can combine the toughness of polymers and the rigidity of inorganic materials, making them more suitable for applications in drilling fluids in complex environments.…”