An Improvement in Thermal and Rheological Properties of Water-based Drilling Fluids Using Multiwall Carbon Nanotube (MWCNT)

Designing drilling fluids for drilling in deep gas reservoirs and geothermal wells is a majorchallenge. Cooling drilling fluids and preparing stable mud with high thermal conductivity are ofgreat concern. Drilling nanofluids, i.e. a low fraction of carbon nanotube (CNT) well dispersed inmud, may enhance the mixture thermal conductivity compared to the base fluids. Thus, they arepotentially useful for advanced designing high temperature and high pressure (HTHP) drillingfluids. In the present study, the impacts of CNT volume fraction, ball milling time, functionalization,temperature, and dispersion quality (by means of scanning electron microscopy, SEM) on thethermal and rheological properties of water-based mud are experimentally investigated. The thermalconductivities of the nano-based drilling fluid are measured with a transient hot wire method. Theexperimental results show that the thermal conductivity of the water-based drilling fluid is enhancedby 23.2% in the presence of 1 vol% functionalized CNT at room temperature; it increases by 31.8%by raising the mud temperature to 50 °C. Furthermore, significant improvements are seen in therheological properties—such as yield point, filtration properties, and annular viscosity—of the CNTmodifieddrilling fluid compared to the base mud, which pushes forward their future development.

Keywords:

Carbon Nanotube , Thermal Conductivity , Water-based Fluid , Mud Viscosity