ZnO-clay nanocomposites for enhance drilling at HTHP conditions

Zinc oxide (ZnO) has received lot of attention as a nanostructured material because of unique properties rendering it for various applications. Severe drilling problems like pipe sticking, formation damage and high torque and drag are common in extended reach hydrocarbon wells that limit the performance of drilling operations. Bentonite (MMT) is commonly used as a rheology modi fier, and attapulgite (ATP) has good Fann viscosity for use in drilling fluids, but both clays face the limitations of flocculation and instability at high temperature and pressure conditions (HTHP). ZnO-clay nanocomposites were formed by incorporating nano-ZnO in nano-modi fied MMT and ATP to maintain remarkable colloidal dispersion and superior rheology, thus enabling homogeneous drilling fluid recipes. ZnO-clay nanocomposites were characterized using scanning electron microscopy and X-ray diffraction. After successive laboratory investigations, drilling fluid compositions of certain proportions of water and MMT in the presence of ZnO-clay nanocomposite yielded perfect stability at high temperatures and pressure, i.e. stable drilling fluid rheology at HTHP conditions. The best-recorded results are reported in this paper, and the properties focused here are the plastic viscosity and yield point.