Organically modified layered magnesium silicates to improve rheology of reservoir drilling fluids

The Effects of Organically Modified Lithium Magnesium Silicate on the Rheological Properties of Water-Based Drilling Fluids

To address the problem of insufficient temperature and salt resistance of existing polymer viscosity enhancers, we designed an organic-inorganic hybrid composite as a viscosity enhancer for water-based drilling fluids, named LAZ, and it was prepared by combining a water-soluble monomer and lithium magnesium silicate (LMS) using an intercalation polymerization method. The composite LAZ was characterized using Fourier transform infrared spectroscopy, transformed target X-ray diffractometry, scanning electron microscopy, and thermogravimetric analysis. The rheological properties of the composite LAZ were evaluated. The composite LAZ was used as a water-based drilling fluid viscosity enhancer, and the temperature and salt resistance of the drilling fluid were evaluated. The results showed that the composite LAZ presented a complex reticulation structure in an aqueous solution. This reticulation structure intertwined with each other exhibited viscosity-enhancing properties, which can enhance the suspension properties of water-based drilling fluids. The aqueous solution of the composite LAZ has shear dilution properties. As shear rate increases, shear stress becomes larger. The yield stress value of the aqueous solution increases as the composite LAZ's concentration increases. The aqueous solution of the composite LAZ exhibits strong elastic characteristics with weak gel properties. The addition of the composite LAZ to 4% sodium bentonite-based slurry significantly increased the apparent viscosity and dynamic shear of the drilling fluid. The drilling fluids containing the composite LAZ had good temperature resistance at 150 °C and below. The rheological properties of brine drilling fluids containing the composite LAZ changed slightly before and after high-temperature aging at 150 °C.

Evaluating the Effect of Claytone-EM on the Performance of Oil-Based Drilling Fluids

This study provides a detailed characterization and evaluation of Claytone-EM as a rheological additive to enhance the performance of oil-based drilling fluids (OBDFs) under high-pressure, high-temperature (HPHT) conditions. It also offers a comparative evaluation of the effectiveness of Claytone-EM with an existing organoclay, analyzing their mineral and chemical compositions, morphologies, and particle sizes. A series of experiments are performed to evaluate Claytone-EM's influence on crucial drilling mud properties, such as mud density, electrical stability, sagging tendency, rheology, viscoelastic properties, and filtration properties, to formulate a stable and high-performing OBDF. Results indicated that Claytone-EM had no significant impact on mud density but remarkably enhanced emulsion stability. Claytone-EM effectively mitigated sagging issues under both static and dynamic conditions, leading to improvements in the plastic viscosity (PV), yield point (YP), apparent viscosity (AV), and YP/PV ratio. The PV, YP, AV, and YP/PV ratios were improved by 11, 85, 28, and 66% increments, respectively, compared with those of the drilling fluid formulated with MC-TONE. The addition of Claytone-EM resulted in enhancing gel strength and improving the filtration properties of the drilling fluid. The filtration volume was reduced by 2% from 5.0 to 4.9 cm3, and the filter cake thickness had a 13% reduction from 2.60 to 2.26 mm. These findings highlight Claytone-EM as a valuable additive for enhancing OBDF performance, particularly under challenging HPHT conditions. Its ability to provide emulsion stability, reduce static and dynamic sag, and control filtration holds the potential to enhance drilling operations, minimize downtime, and bolster wellbore stability. This study acknowledges certain limitations, including its temperature range, which could benefit from exploration at extreme temperatures. Additionally, the absence of flow experiments limits a comprehensive understanding of sag effects, and further research and field-scale evaluations are recommended to validate and optimize the application of Claytone-EM in OBDFs.