The volume and type of solids in a drilling mud system can adversely affect mud properties, reduce penetration rates, cause damage to drilling equipment, and increase total drilling costs. Efficiency controlling the solids content of the mud system is an important phase of an efficient and cost-effective drilling program. The three basic methods of removing solids are dilution and/or displacement of whole mud, settling and mechanical solids-control equipment.
An important problem in the oil industry is the treatment of produced water, especially in the case of offshore oil production where space and floor area, needed for the separation equipment, are extremely costly. Increased production of water occurs when an oil field matures, and the availability of efficient and cost-effective techniques partly determines the period during which economic production is possible. For the final de-oiling process several techniques are available, of which plate separation, centrifugation and the use of hydrocyclones are important ones. Common characteristics of these three techniques are that only insoluble oil components can be removed, and that the prevailing separation process is movement of the oil droplets with respect to the continuous phase, water, as a result of an external force, viz. the gravity force or the centrifugal force.
Oil-based drilling fluids have long been recognized as a sound technical answer to problems encountered in deep-hot holes and, more recently, to stabilize boreholes with thick intervals of reactive clay formations. However, oil-based mud product development was slowing down until the introduction of low toxicity base oils in the late seventies created a need for new investigations. This innovation sparked a resurgence of oil mud research and development which has resulted in oil-based mud (OBM) systems being used routinely in many active drilling areas worldwide.