Potential of co-precipitated synthesized iron oxide nanoparticles on the rheological properties and filtration loss control of water-based drilling fluids at high temperature and high pressure conditions

Article history: Received 02 April 2019 Accepted 16 July 2019 The antagonistic conditions such as high temperature and pressures encountered as drilling operations cut deeper into formations require powerful drilling mud formulae that would provide the thermal stabilization of the drilling fluids while maintaining their rheological integrity. The present work investigates the synthesis of hematite (Fe2O3) nanoparticles through a simple chemical precipitation method to be used as failure resistance modifier for water-based drilling fluids (WBFs) at high temperature/high pressure (HTHP) conditions. The surface morphology revealed by transmission electron microscopy (TEM) strategy suggested that the employed iron oxide nanoparticles (IONPs) are mainly present as big spherical shaped particles and are well crystallize in nature with an average diameter less than 50 nm. Scanning electron microscopy (SEM) technique confirmed the shape and size of the produced nanoparticles. The chemical composition of the synthesized Fe2O3 nanoparticles was confirmed by energy dispersive analysis of X-rays (EDX). Three water-based drilling fluids (WBFs) samples; blank unmodified, surface modified 1 g iron oxide nanoparticles (IONPs-A) and modified 2 g (IONPs-B) were prepared and studied. The rheological properties and filtration ability were investigated for the utilized samples at both 500 psi and 350°F (HTHP). The results of this study demonstrated that the addition of 1 g of IONPs to the drilling fluid sample displayed that the plastic viscosity (PV) was recorded at 8 cP and thixotropy at 2 lb/100 ft2 under HTHP conditions without mud failure due to establishing highly stable multiple bentonite-IONPs bridging effect. Also, filtration for IONPs-1 sample showed enhanced sturdy filter mud cake and confirmed the resistance of this modified sample to the failure occurred for the blank drilling mud at these harsh thermal conditions.