Impact of barite and ilmenite mixture on enhancing the drilling mud weight

It is common knowledge in the technology of drilling fluids, monitoring of the drilling mud weight is critical in developing a mud system that yields good well stability. Alternative weighting materials should be in demand to offer superior properties such as barite, available in sufficient reserves to meet field requirements and be competitively priced. A weighting material that can be sourced locally to substitute barite would be a good innovation in the drilling industry. The present work was performed for enhancement the weighting of the drilling fluids by using mixture of barite and ilmenite. Micro-sized ilmenite ore (FeTiO3) particles were obtained by a direct solid phase milling process to replace a certain percentage of barite as weighting material of the drilling mud. X-ray diffraction (XRD) analysis was carried out to underline the phase identification of the crystalline ilmenite, used drilling mud weighting agent as barite and Na-bentonite particles. The lamellar shape and the arrangement in overlapping plates of ilmenite particles, Platy-like shaped Na-bentonite grains against sub-angular and square-shaped barite particles were confirmed by scanning electron microscope (SEM) technique. Three mud samples with different densities were prepared which be made up of fresh water, sodium bentonite and weighting material. The weighting materials were added up to the mud separately to form the required mud density ranges between 8.65 and 18 lb/gal. The first sample was water-based mud with barite; second sample was water-based mud with local ilmenite ore and third sample was water-based with barite and ilmenite in which were added in parts as 50:50 by ratios. These samples were investigated at different temperatures (normal, 120, 160, 180 °F) and the employed mud density range to determine solid content, density, rheological properties and filtration losses. The study showed that the rheological properties of barite/ilmenite mixture were found to give comparable results as barite and has the potential to be used as alternative weighting material especially in a heavier drilling mud. Two significant advantages could be observed through using the mixture; it produces lower solids content and fluid loss which in turns reduces the formation damage, respectively. Keywords: Drilling mud weight, Ilmenite ore, Barite/ilmenite mixture, Rheology, XRD, SE