Processes · 2023 · 25 citations · 40 references
EngineeringPetroleum EngineeringDrillingDrilling EngineeringReservoir EngineeringDrilling FluidsDrilling OperationsWellbore StabilityCholine Chloride-based SolventsDeep Eutectic SolventsDrilling Fluid AdditivesDrilling Fluid InhibitionDrilling Fluid PropertiesDrilling Fluid RheologyShale InhibitionWater-based Drilling Fluids
Shale formations cause about 70 % of wellbore instability, and while salts, silicates, polymers, ionic liquids, and DES have been used as shale inhibitors, their limitations and waning popularity have prompted interest in natural deep eutectic solvents (NADES). This study evaluates an in‑house Ascorbic acid–glycerine NADES as a drilling‑fluid additive for shale inhibition and compares its performance to KCl, an imidazolium ionic liquid, and a choline chloride DES. The authors used surface‑tension measurements, d‑spacing analysis, zeta‑potential, and FESEM imaging to elucidate how the NADES stabilizes clay and improves fluid properties. At 3 % concentration, the NADES reduced mud‑cake thickness by 39.7 %, filtrate volume by 28 %, achieved 77.8 % shale inhibition and 87 % shale recovery, and improved the yield‑point to plastic‑viscosity ratio, making it a promising non‑toxic, inexpensive additive.
During drilling, almost 70% of wellbore instability issues result from the encountering of shale formations. Various additives such as salts, silicates, and polymers are used in water-based mud to enhance its shale-inhibition capability; however, such additives have certain limitations. Lately, ionic liquids and deep eutectic solvents (DES) have been used by various research groups as shale inhibitors in drilling fluid due to their biodegradability and efficacy. However, their popularity faded when a natural derivative of DES, i.e., Natural Deep Eutectic solvent (NADES), came into the picture. This research utilizes the in-house-prepared Ascorbic acid and Glycerine (AA:Gly)-based NADES as a drilling fluid additive for shale inhibition and compares its efficacy with counterpart inhibitors such as KCl, imidazolium-based ionic liquid, and Choline Chloride-based DES. The results show that 3% NADES improved the overall Yield point to Plastic viscosity ratio, with a 39.69% decline in mud cake thickness and a 28% decline in the filtrate volume of drilling mud. Along with improved drilling fluid properties, 3% NADES resulted in 77.77% shale inhibition and 87% shale recovery. Surface tension, d-spacing, zeta potential, and FESEM have been conducted to justify and elucidate the inherent mechanism behind the working of NADES as a drilling fluid additive and clay stabilizer. Thus, Ascorbic acid-based NADES is recommended as a potential non-toxic and cheap drilling fluid additive to improve drilling fluid properties and clay stability.
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Laboratory characterisation of shale properties
Matthew Josh, Lionel Esteban, Claudio Delle Piane et al. · Journal of Petroleum Science and Engineering · 2012 · 601 citations · Full text
Engineering, Earth Sciences, Geology +17