Comparative study of using Water-Based mud containing Multiwall Carbon Nanotubes versus Oil-Based mud in HPHT fields

Water-Based mud (WBM) and Oil-Based mud (OBM) are the most common drilling fluids currently used and both have several characteristics that qualify them for High Pressure High Temperature (HPHT) purposes. This paper compares the different characteristics of WBM containing Multiwall Carbon Nanotubes (MWCNTs) and OBM to help decide the most suitable mud type for HPHT drilling by considering mud properties through several laboratory tests to generate some engineering guidelines. The tests were formulated at temperatures from 120 °F up to 500 °F and pressures from 14.7 psi to 25,000 psi. The comparison will mainly consider the rheological properties of the two mud types and will also take into account the environmental feasibility of using them. The results showing that the Water-Based offers a more environmental friendly choice yet some of additives that are used to enhance its performance at (HPHT) conditions, such as (MWCNTs), thus it is necessary to develop new formulas for (HPHT) Water-Based muds that could act like Oil-Based mud but cause less harm to the environment.