Synthesis and mechanism research of a new low molecular weight shale inhibitor on swelling of sodium montmorillonite

Abstract

Shale gas as green and clean energy is attracting more interest. However, shale hydration and swelling have become the major challenges using water‐based drilling fluids, replacing oil‐based drilling fluids, for developing shale gas. In this work, a low molecular weight branched polyamine (NETS) as clay swelling inhibitor was synthesized. The NETS performed excellent inhibition property by linear expansion experiments and cuttings hot‐rolling recovery. The inhibition mechanism of NETS was investigated using X‐ray diffraction, fourier transform infrared spectroscopy, cation exchange capacity, X‐ray photoelectron spectroscopy, scanning electron microscopy, and zeta potential. The results show that the NETS can adsorb on Na‐Mt, decrease the basal spacing of wet Na‐Mt from 1.91 to 1.43 nm, and replace majority sodium ions from interlayer of Na‐Mt. However, replaceability of sodium ions and inhibition of water molecules of ethylenediamine are worse than NETS. These indicate that the primary amines of NETS had strong interaction with Na‐Mt, tensed clay layers and decrease the basal spacing. The combination of long hydrophobic chain and primary amines makes NETS to adsorb on surface of Na‐Mt, intercalate into interlayer of Na‐Mt with tilted monolayer arrangement, and replace sodium ions. The more the number of primary amine groups, the better the inhibition performance. Therefore, NETS has a great potential to be an outstanding shale inhibitor of water‐based drilling fluids in the future.

The role of molecular modelling and simulation in the discovery and deployment of metal-organic frameworks for gas storage and separation

“…Note that in the high-throughput screenings below, natural gas is approximated as methane. As a caveat, a computational study by Zhang et al found that, when considering the influence of larger hydrocarbons contained in natural gas, the ranking of MOFs for natural gas storage could differ from when approximating natural gas as pure methane [212].…”

Novel Deep Eutectic Solvents for Stabilizing Clay and Inhibiting Shale Hydration

“…However, the high cost and high environmental load of OBDF greatly limit its application. 11,12 The new generation of SBDF has greatly improved compared with OBDF in terms of performance and environmental protection. For example, ester-based drilling fluid (EBDF) with biodiesel (monoalkyl ester) as the base oil has a higher flash point than OBDF, and most importantly, it has a huge advantage in environmental protection.…”

“…Among them, the action of shale and water in the drilling fluid can easily cause the well wall to collapse and trap drills. , Oil-based drilling fluids (OBDF) and synthetic-based drilling fluids (SBDF) are the best choice for reducing shale hydration and swelling problems, because the oil phase in them is generally considered to have an extremely low coefficient of friction. However, the high cost and high environmental load of OBDF greatly limit its application. , The new generation of SBDF has greatly improved compared with OBDF in terms of performance and environmental protection. For example, ester-based drilling fluid (EBDF) with biodiesel (monoalkyl ester) as the base oil has a higher flash point than OBDF, and most importantly, it has a huge advantage in environmental protection. − However, the upper temperature limit of the biodiesel invert emulsion for applications is 135 °C, which indicates that its application at high and ultrahigh temperatures needs further research .…”

Inhibition Impact of Amino Acids on Swelling Clays: An Experimental and COSMO-RS Simulation Evaluation

“…30 Recently, the use of ultra-low-molecularweight organic clay stabilizers in WBFs has been suggested as the best choice for all types of shale formation. 31,32 Again, the move toward compounds that leave little or no environmental footprints is increasing due to the stringent rules from environmental agencies. 33,34 The search for monomeric organic compounds from natural extracts, with shale inhibition potentials similar to or better than the conventional clay stabilizers, like KCl, is on the rise.…”

“…Furthermore, in cases where the smectite composition in the shale formation is higher, KCl exhibits limited performance . Recently, the use of ultra-low-molecular-weight organic clay stabilizers in WBFs has been suggested as the best choice for all types of shale formation. , …”