RHEOLOGICAL PROPERTIES

This study investigates the effect of increasing temperature on the rheological properties of water based drilling mud, which is critical for optimizing drilling operations. The rheological properties analyzed include plastic viscosity (PV), yield point (YP), and gel strength (GS), which play a vital role in the performance and efficiency of drilling fluids. As temperature can significantly influence the flow behavior and stability of the drilling mud, understanding these changes is essential for ensuring the mud’s ability to suspend drill cuttings, maintain wellbore stability, and reduce friction during drilling operations. The study examines a temperature range from 100°F to 160°F, reflecting typical downhole temperature conditions encountered during drilling operations. To achieve this, laboratory experiments were conducted on formulated WBM samples subjected to a controlled temperature range. Rheological measurements were taken using a viscometer at various rotational speeds (600, 300, 200, 100, 6, and 3 RPM) to calculate PV, YP, and gel strengths. The results were analyzed using regression analysis in Microsoft Excel to assess the relationship between temperature and each rheological parameter. Data trends and correlation coefficients were used to determine the degree of influence temperature has on each property. The results revealed that increasing temperature had a notable effect on the rheological behavior of the mud. Plastic viscosity showed a decreasing trend with rising temperature, indicating reduced fluid resistance, while the yield point and gel strengths generally declined, suggesting weakened structural integrity of the mud. The regression models demonstrated strong correlations, supporting the reliability of the findings. The study concluded that temperature significantly influences WBM rheology, which must be accounted for in high-temperature drilling environments to maintain mud performance and ensure operational efficiency.

This research examines how Sodium Hydroxide (NaOH) influences the flow characteristics of purified gum Arabic-based drilling mud formulations, positioning them as eco-friendly substitutes for conventional synthetic additives. The experiment involved developing seven initial formulations combining bentonite with different polymer systems: xanthan gum, gum Arabic, and mixtures of gum Arabic with either cocoyam starch or ginger extract in proportions of 50/50 and 75/25. Subsequently, selected formulations underwent alkaline modification using NaOH at measurements of 3.0g, 7.5g, and 15.0g to replicate varying pH environments. Flow behavior parameters encompassing plastic viscosity (PV), yield point (YP), gel strength, and mud weight were determined through Fann viscometer measurements and evaluated against three mathematical model frameworks: Bingham Plastic, Power Law, and Herschel- Bulkley models. Experimental findings demonstrated that 50g of gum Arabic delivered comparable rheological characteristics to 1g of xanthan gum under neutral conditions. The introduction of alkaline treatment produced substantial modifications in fluid behavior, with response patterns dependent on both the specific polymer-starch pairing and alkalinity level. The most remarkable transformation occurred in the gum Arabic-cocoyam (50/50) formulation treated with 7.5g NaOH, which demonstrated PV of 65 cp and YP of 180 lb/100ft² corresponding to increases of 261% and 1025% respectively relative to the 3.0g NaOH variant. The gum Arabic-ginger combination displayed considerable viscosity nhancement (PV = 108 cp with 7.5g NaOH) yet revealed temporal degradation of gel structure at elevated alkalinity levels. Every alkaline-treated system manifested pseudoplastic (shear-thinning) characteristics with flow behavior indices (n) spanning 0.3 to 0.948, validating their appropriateness for drilling fluid applications. Comparative model analysis indicated that the Herschel-Bulkley model most accurately characterized the behavior of alkaline-modified natural polymer systems, whereas both Bingham Plastic and Power Law models exhibited substantial prediction errors, especially under high-alkalinity conditions. These results established that purified gum Arabic, when strategically combined with indigenous starches, (cocoyam & ginger) and subjected to pH optimization, represents a viable, environmentally degradable, and economically advantageous alternative to synthetic drilling fluid components, delivering ecological v advantages while preserving operational performance standards required for petroleum drilling activities.

Background: The stability of pharmaceutical suspensions depends on their rheological properties, which are influenced by the type and concentration of suspending agents. This study evaluated and compared the rheological properties and performance of various suspending agents in ibuprofen suspension formulations. Methodology: Ten suspending agents Chitosan, Sodium Alginate, NaCMC, HPMC, HEC, Carbopol, CMEC, MC, Eudragit L-100, and PVP, were prepared using appropriate solvents. Eudragit L-100 was dissolved in ethanol, HEC, HPMC, and Carbopol in hot water, Chitosan in 1% H₂SO₄, while others were dispersed in distilled water. Each was evaluated for pH,
density, and viscosity. Six agents (NaCMC, CMEC, Sodium Alginate, MC, HPMC, and Carbopol) were selected to formulate ibuprofen suspensions, assessed for pH, viscosity, and sedimentation rate at ambient temperature. Results: All suspending agents produced formulations with acceptable pH (4.1–5.9). Viscosity increased with polymer concentration; Carbopol and NaCMC at 1.0% formed gel like systems, while0.5%gave smooth, pourable suspensions. Sedimentation tests showed the control settled rapidly, whereas Carbopol and NaCMC formulations exhibited the highest stability with uniform sedimentation over seven days. Conclusion: All agents improved suspension stability, though performance varied with concentration. Carbopol and NaCMC at 0.5% provided the best balance between viscosity and pourability, making them most suitable for ibuprofen suspensions