Effect of pH on Rheological and Filtration Properties of Water-Based Drilling Fluid Based on Bentonite

Abstract

The design of drilling fluids is very important for the drilling operation success. The rheological properties play a key role in the performance of the drilling fluid. Therefore, studying the mud rheological properties of the water-based drilling fluid based on bentonite is essential. The main objectives of this study are to address the effect of pH changes on the rheological and filtration properties of the water-based drilling fluid based on bentonite and to provide a recommended pH range for this drilling fluid for a safe and high-performance drilling operation. Different samples of the water-based drilling fluid based on bentonite with different pH values were prepared, and the rheological properties such as plastic viscosity, yield point, and gel strength were measured. After that, the filtration test was performed under 300 psi differential pressure and 200 °F. The pH for the water-based drilling fluid based on bentonite significantly affects the mud rheology. The shear stress and shear rate relation were varying with the change in the pH. Increasing the pH from 8 to 12 resulted in decreasing the plastic viscosity by 53% and the yield point by 82%, respectively. The ratio of yield point / plastic viscosity was 1.4 for pH of 8 while it decreased to 0.5 for a pH of 11 and 12. There was a significant decrease in the gel strength readings by increasing the pH. The filtrate volume and filter cake thickness increased by increasing pH. The filtration volume increased from 9.5 cm3 to 12.6 cm3 by increasing the pH from 9 to 12. The filter cake thickness was 2 mm at 9 pH, while it was increased to 3.6 mm for 12 pH. It is recommended from the results to keep the pH of water-based drilling fluid based on bentonite in the range of 9 to 10 as it provides the optimum mud rheological and filtration properties. The findings of this study illustrated that keeping the pH in the range of 9 to 10 will reduce the plastic viscosity that will help in increasing the rate of penetration and reducing the required pump pressure to circulate the mud to the surface which will help to sustain the drilling operation. In addition, reducing the filtrate volume will produce a thin filter cake which will help in avoiding the pipe sticking and protect the environment. In general, optimizing the pH of the water-based drilling fluid based on bentonite in the range of 9 to 10 will improve the drilling operation and minimize the total cost.

Improvement of rheological and filtration characteristics of water-based drilling fluids using naturally derived henna leaf and hibiscus leaf extracts

“…For the HLE product, the pH of the WBDF system at 9.3 decreased with an increase in HLE concentration (between 4.86 and 4.72), while the reverse was the case when HBLE (between 5.84 and 7.47) was introduced into the WBDF system. The data of the pH of A-0 = Base fluid 50 g/L KCl + 100 g/L + NaCl + 7.0 g/L PAC LV + 2.0 g/L PHPA A-1 = A-0 + 25 g/L HLE 320 ml distilled water + 50 g/L KCl + 100 g/L + NaCl + 7.0 g/L PAC LV + 2.0 g/L PHPA + 25 g HBLE A-2 = A-0 + 25 g/L HBLE 320 ml distilled water + 50 g/L KCl + 100 g/L + NaCl + 7.0 g/L PAC LV + 2.0 g/L PHPA + 25 g/L HBLE the HLE product corroborated the reports of Moslemizadeh et al (2015) in that Henna leaf extracts are acidic in aqueous solution, while Hibiscus leaf is slightly acidic between the pH of 5.5 and 7.5 (Gamal et al 2019). It is generally believed that Henna extracts solution in water removes the hydrogen atoms from the chemical structure of its constituents, resulting in a consequent reduction of the pH of the solution (Gamal et al 2019).…”

“…Drilling fluid additives are developed to be mixed with water with a pH level from 8.5 to 10 for the needed chemical reaction to occur and to provide a proper yield (Gamal et al 2019). After mixing and preparing the WBDF system, the mud pH was measured at 78 °F and the results are presented in Fig.…”

Functional properties of syrup from malted and unmalted rice of different varieties: A comparative study

“…Syrup from centrifuged group obtained significantly higher ( P < 0.05) TA compared to filtered group. Plausibly, fluid acidity might affect both filter cake formation rate and filtrate volume (Gamal, Elkatatny, Basfar, & Al‐Majed, 2019), but not in centrifugation that seemed unaffected in this current study.…”

Formulation of cellulose using groundnut husk as an environment-friendly fluid loss retarder additive and rheological modifier comparable to PAC for WBM

“…A desirable drilling fluid is alkaline in nature and has a pH range of 9-10 as it ensures that the drilling fluid shows optimum rheological and filtration properties (Li et al 2018;Gamal et al 2019). This helps decrease the plastic viscosity which leads to an increase in the Rate of Penetration (ROP) thereby reducing the required pump pressure to circulate the mud to the surface, effectively reducing time, and helps in sustaining the drilling operations.…”