Evaluation of the viability of nanoparticles in drilling fluids as additive for fluid loss and wellbore stability

Abstract

Wellbore instability is an issue that, if left untreated, can cause wells to collapse, resulting in human, environmental, equipment, and revenue losses. Drilling fluids have been used to enhance the drilling process by lubricating and cooling the drill bit, eliminating cuttings, and most importantly, by improving the stability of the well by preventing fluid loss. However, there has been an increase in operational demands and challenges that call for drilling fluids to be more effective, economical, sustainable, and environmentally friendly. With shales that have infinitesimally small pores, nanoparticle additives in drilling fluids can be crucial in providing the properties that are necessary to prevent fluid loss and provide wellbore stability while meeting the operational demands of the present day. Therefore, this paper examines the use of nanoparticle additives including copper (II) oxide (CuO), magnesium oxide (MgO), and aluminum oxide (Al₂O₃) where they are tested under three conditions using the permeable plugging tester (PPT), high-temperature high-pressure (HTHP) fluid loss apparatus, and API low-temperature – low-pressure (LTLP) fluid loss apparatus under concentrations of 0.03% and 0.10%. Finally, based on the results, each nanoparticle sample (particle sizes between one and 100 nm) performed well in contributing to the aim of this project. CuO is the most effective inhibitor across all concentrations and under the three different conditions. It contributed to reducing the fluid loss from 37.6 mL to 18.2 and 13.2 mL, which is between 52% and 65% of fluid reduction. For MgO, it contributed to fluid loss reduction to 23.8 mL and 15 mL, which translated to 37%–60% of fluid loss reduction. The use of Al₂O₃ nanoparticles resulted in a fluid loss reduction to 33.6 mL and 17.8 mL, reducing the fluid loss up to 11%, at HTHP and up to 53% at LTLP. Unlike CuO and MgO, Al₂O₃ was less effective under HTHP conditions when compared to LTLP conditions. Al₂O₃ did not suffer as a significant diminishing benefit with increasing concentration in LTLP conditions however which means that at a higher concentration, it may begin to be more effective. Each material used in this study has its own specific and technical characteristics that will help create a progressive amount of property, such as providing stability and withstanding the high-temperature and high-pressure condition downhole.