Hematite, in the context of drilling fluid, is a high-density weighting agent used in drilling fluid in the oil and gas industry. Hematite is an iron oxide with the chemical composition Fe2O3 and is abundant on the earth’s surface and in the shallow crust. Pure hematite consists of 70% iron and 30% oxygen by weight, and the high-density ore has a mica-like crystal structure. For use in drilling fluids, the hematite is ground into a suitable particle size.
Trenchlesspedia Explains Hematite
Hematite and barite are the most commonly used weighting agents in the drilling industry that meet specifications by the American Petroleum Institute (API) and the International Organization for Standardization (ISO). Weighting agents are added to the drilling mud to maintain sufficient bottomhole pressure (BHP) and prevent the undesired influx of formation fluid, also known as a kick.
Hematite is denser than barite, with a minimum specific gravity of 5.05 g/cm3. Hematite also occupies less space than an equal mass of barite, reducing the interaction of the solids in the fluid. Drilling fluid weighted with hematite will, therefore, have fewer solids by volume, improving its rheological properties, increasing the penetration rate and reducing the mud cost.