M-I, known as M-I SWACO, supplies drilling and completion fluids and additives to oil and gas companies in more than 75 countries worldwide. Its fluids cool and lubricate drill bits, remove rock cuttings, and maintain the stability of the wellbore. Through M-I's SWACO division, the company provides pressure control, rig instrumentation, and drilling waste management products and services. It is also a worldwide producer of barite and bentonite used by the oil and gas and industrial markets. Drilling fluids provide the company with more than half of its sales. M-I SWACO is owned by Schlumberger Limited.