It is necessary to organize production of low-solid-point base oils with good viscosity and temperature properties -a high viscosity index (VI) and low solid point -for obtaining lube oils with a high level of performance properties. These properties are ensured by rational selection of the feedstock (crude oil) and highly efficient technology, including a combination of hydrocatalytic processes.In many sectors, synthetic oils with better low-temperature properties, alkylbenzene and ester oils in particular, are used due to the limited possibilities of crude oils. However, due to the expensiveness, toxicity, and unsatisfactory anticorrosion properties, synthetic oils are preferably used as components of petroleum oils, limiting their content to 10-25%. Mixed (semisynthetic) base oils have fewer drawbacks than petroleum and synthetic oils.Poly-a-olefin oils have been most investigated and are the most common as a component of semisynthetic oils. They are much (by 4-5 times) more expensive than mineral oils, but in comparison to mineral oils obtained with hydrocatalytic processes, they have good viscosity-temperature and antioxidant properties. Despite the drawbacks, basically due to the surface properties and manifested during use, base oils from ethylene oligomers have been manufactured by such well-known companies as Mobil, Chevron, Gulf, etc., since the 1970s.The following must be organized for production of oils from a mixture of mineral and poly-a-olefin oils: