Deep Eutectic Solvents for Enhancing the Rheological Behavior of Polymers and Clays in Polymeric Water-Based Drilling Fluids

Abstract

Drilling fluids with high suspending capacity without high viscosity are required in drilling operations, such as horizontal wells and highly deviated wells, with the “cutting bed”. Non-viscosifying rheological modifiers that can enhance the rheological properties of polymer drilling fluids are urgently needed. This study reports the application of a choline-chloride-based deep eutectic solvent (Gly-DES) as a rheological modifier for polymeric water-based drilling fluids. The rheological effects of Gly-DES on bentonite/polymer fluids were evaluated by high-temperature rheological testing, rheological model fitting, and rheological parameter (yield point, fluidity index, gel strength, etc.) analysis. The results showed that 2–4 wt % Gly-DES can improve the rheological properties of polymer drilling fluid in the temperature range of 150 °C. The addition of Gly-DES significantly improved the rheological parameters of drilling fluids, such as the yield point, gel strength, low shear rate viscosity, etc. At the same time, the viscosity of drilling fluids was always stable at different temperatures, which means that Gly-DES can help improve the suspension and cutting carrying capacity of drilling fluids without significantly increasing the viscosity of drilling fluids. Mechanistic analysis revealed that Gly-DES was connected to the polymer and bentonite through hydrogen bonds and ionic bonds, which enhanced the cross-linked network structure of the polymer at high temperatures and promoted the formation of weak gels in Na bentonite suspensions. Gly-DES can simultaneously enhance rheology, inhibit clay hydration, and improve filter cake lubricity and has the potential to be a multifunctional drilling fluid treatment agent.

Deep Eutectic Solvents: Comprehensive Review and Future Directions on Synthesis and Oilfield Applications

“…Nevertheless, in underground formations, nearly all of these additives showed instability when exposed to the extreme conditions of elevated temperature and pressure. Recently, DESs have been propose as drilling fluid additives. − Due to their thermal stability and ability to generate viscous fluids, these environmentally friendly chemicals are seen as viable substitutes for conventional surfactants that are ineffective in severe environments. Research on the use of DESs in drilling engineering can be categorized into two groups: (i) DESs as shale inhibition agents (ii) DESs as mud loss control agents and (iii) DESs as Oil-based drill cuttings.…”

“…Shale consists mostly of clay minerals, making it vulnerable to water. 121,122 The shale becomes hydrated as a result of physical and chemical reactions between the drilling fluid and the shale. This causes the shale to swell, resulting in many complex issues such as sinking, tight holes, bit balling, blocked pipe, sloughing, and, in the most severe cases, the loss of wells.…”

The Phase Inversion Mechanism of the pH-Sensitive Reversible Invert Emulsion

“…In light of the current main use of reversible emulsion, organic clay is required to be added to the reversible emulsion drilling fluid system to adjust the rheological properties and stability of the reversible emulsion drilling fluid [31,32], so as to improve the cuttingcarrying performance of the reversible emulsion drilling fluid [33]. Therefore, studying the influence of organic clay on reversible emulsions is beneficial for the promotion and application of homemade reversible emulsion systems in oil fields.…”

Nano-Grafted Acrylamide Copolymer as an Anti-Temperature and Anti-Calcium Fluid Loss Agent for Water-Based Drilling Fluids

“…Drilling fluids are essential to drilling operations in the same way as blood is to the human body. − Water-based drilling fluids (WBDFs) are prioritized despite the fact that oil-based drilling fluids perform better than they do in terms of performance because of the high cost of oil-based drilling fluids and their poor environmental performance. − Water, bentonite, and other treatment agents are the main ingredients of WBDFs, which are still the most frequently used drilling fluids in drilling operations. , Free water in the drilling fluid intrudes into the formation as a result of the pressure differential between the formation and the borehole . Yet, significant water loss results in drilling that is extremely stuck, wellbore collapses, damages to the formation, and even reduces drilling efficiency. , …”

“…5−7 Water, bentonite, and other treatment agents are the main ingredients of WBDFs, which are still the most frequently used drilling fluids in drilling operations. 8,9 Free water in the drilling fluid intrudes into the formation as a result of the pressure differential between the formation and the borehole. 10 Yet, significant water loss results in drilling that is extremely stuck, wellbore collapses, damages to the formation, and even reduces drilling efficiency.…”