As sensitive and electro-chemically active additives, anionic nanoparticles can be used to develop various water-based mud designs to fulfill different drilling conditions with less costs. For an optimum performance, however, they must be carefully selected and formulated. The objective of this study was to compare and evaluate various properties of water-based nanomuds. This was achieved by investigating the impact of very low concentrations of commercially affordable three types of negatively charged nanoparticles on the rheological, hydraulic and filtration properties of a high pH "flocculated" water-based mud. Simultaneously, the superior and insufficient types and concentrations were explored.
In this research, four concentrations of each of anionic nanosilica, nanotitanium, and nanoaluminum were used to treat the high pH (11.5-12) water-based mud. Sequences of API experimental tests were conducted by using standard Low Pressure Low Temperature (LPLT) filtration and rheological devices for all samples. For the hydraulic evaluation, a commercially available software was used to simulate the impact of the nanoparticles on the equivalent circulation density (ECD) and the drillpipe circulation pressure in a typical directional well.
The results show significant improvements in the rheological and hydraulics properties of the flocculated water-based muds treated by 0.1% wt. or less of nanosilica and 0.3% wt. or less of nanotitanium and nanoaluminum. For the higher concentrations, no more improvements were obtained. Further, the results show the ability of nanosilica and nanotitanium to reduce the filtration volume and no filtration reduction based on nanoaluminum. However, all the nanoparticles enhance the mudcake structure, but differently, and prevent the spurt water loss completely.
The current nanoparticle types can be used to develop a qualified mud design, thereby reducing drilling problems, such as stuck pipe, formation damage, wellbore instability, downhole equipment failure, mud circulation loss, and shale swelling if they are properly formulated. Thus, the more complicated wells can be drilled by using water-based nano muds and by eliminating the high costs and bad environmental impacts of using oil-based muds.