Effect of zinc titanate nanoparticles on rheological and filtration properties of water based drilling fluids

The aim of this work is to evaluate the effect of laboratory synthesized ZnTiO3 nanoparticles on rheological and filtration characteristics and their response to heating in a drilling fluid. This work is the first study where the use of zinc titanate (ZnTiO3) nanoparticles is reported to improve the rheological and filtrate loss properties of water based drilling fluid (WBDF). The role of nanoparticles is examined by performing a comparative study on drilling fluid properties by incorporating the ZnTiO3 nanoparticles from 0.05 to 0.30 w/v% in mud formulations. The nanoparticles are obtained by two different synthesis approaches: (a) sol-gel bulk polymerization method (SNP), and (b) sol-electrospinning technique (ENP). These two methods yield nanoparticles with different mean sizes and size distributions. The experimental work has been carried out to investigate the influence of concentration of ZnTiO3 nanoparticles on fluid rheology at 20 degrees C and 70 degrees C and API filtrate at normal temperature and 100 psi pressure according to American Petroleum Institute (API) methodology. The mud samples are subjected to ageing process in hot rolling oven at 110 degrees C for 16 h to study thermal stability and the effect of ageing on rheological and filtration properties. The experimental results show that ZnTiO3 nanoparticles significantly affect to the drilling fluid properties and considerably decrease the filtrate loss and improve thermal stability and rheological properties. Apparent viscosity (AV) for base mud indicated similar to 27% decrease on heating up to 70 degrees C, however, this decrease due to temperature rise is reduced by the addition of 0.30 w/v% nanoparticles (only 6% for SNP and 10% for ENP). It is also found that ageing of base mud at 110 degrees C caused similar to 17.3% reduction in AV at 20 degrees C and similar to 31.5% reduction at 70 degrees C. However, this decrease in AV due to hot rolling ageing was reduced by addition of 0.30w/v% nanoparticles (similar to 6% for SNP and similar to 12% for ENP) at 20 degrees C. AV was found to initially decrease and then increase with increasing concentration of nanoparticles. On addition of 0.30 w/v% nanoparticles, the AV of the hot rolled base mud increased by similar to 9.3% (21.5-23.5) for SNP, and by similar to 20.9% (21.5-26) for ENP. API filtrate of base mud, after hot rolling, reduced by 33% and 35.86% on using 0.30% (w/v) nanoparticle concentration of SNP and ENP, respectively which is a remarkable influence of NP as a fluid loss reducer. This effect can arise due to size, shape and surface area of the added nanoparticles.