Experimental investigation of rheological behaviour and stability of mud system using novel image processing application in presence of activated carbon and silica-coated iron oxide nanoparticles

The success of any drilling activity is mainly dependent on the behaviour of the drilling fluid. These fluids not only act as a primary barrier but are also responsible for maintaining hole integrity, carrying and lifting the drilled cutting and preventing the fluid loss. All these characteristics can be achieved by the help of desired rheological properties. Silica-coated iron oxide nanoparticles (0.25 and 0.5 wt. %) and activated carbon (0.25 and 0.5 wt. %) are being utilised in this study to formulate stable and high-performance water-base drilling fluids. The rheological characteristics of the mud system were investigated using different rheological parameters that consist of plastic viscosity, yield point, apparent viscosity and gel strength. On the other hand, the stability of the mud systems was observed with the help of intensity profile plots and interactive 3D surface plots using image processing technique. It is a novel method of spotting the changes in mud stability under no circulation condition. The results of the study reveal that all the muds showed pseudo-plastic shear thinning behaviour with flow index < 1. No substantial changes in mud density were recorded after the addition of these particles. The maximum mud weight of 8.8 ppg was recorded in activated carbon samples. All the rheological properties were obtained at ambient conditions of 27 °C. It was observed that samples 1 and 4 demonstrate rheological characteristics in the desired operating range with optimum yield point-to-plastic viscosity ratio in range of 0.75–1 \(\frac{{{\raise0.7ex\hbox{${lb}$} \!\mathord{\left/ {\vphantom {{lb} {100ft^{2} }}}\right.\kern-0pt} \!\lower0.7ex\hbox{${100ft^{2} }$}}}}{cP}\). This ratio indicates that the concentration of both the particles is the key factor in achieving desire cutting carrying capacity. Moreover, according to intensity profile plots for the determination of mud stability, the sample with least concentration of activated carbon was the most stable sample. No substantial change in stability was recorded in that sample after two days of experimentation. On the contrary, silica-coated iron oxide nanoparticles start to de-phase on Day 1, and separation was quite visible on Day 2. On Day 5 of the stability test, it was perceived with the help of 3D surface plots that each sample was undergoing either solid settling phenomenon or dephasing. Based on the findings of the study, it can be concluded that activated carbon because of its high surface area and nontoxic behaviour can act as an efficient additive in terms of maintaining the rheological properties and stability of water-based mud system.