The article discusses researches performed in the Well Drilling Department of the St. Petersburg Mining University. The directions of development of the department are shown. Special attention in this article is paid to research in the field of developing drilling fluids for drilling wells in various mining and geological conditions. It is shown that the gas-liquid mixtures studied by the department will be effective for under balanced drilling under conditions of abnormally low reservoir pressures when using a binary mixture of sodium lauryl sulfate 0.5% + linear sodium alkyl benzene sulfate 0.5% as a surfactant and polyacrylamide FP complex 107 (0.05%) as a forming and stabilizing additive + carboxymethyl starch BUR-2 (1%). Studies in the field of development of inhibitory fluids have shown that an increase in the concentration of polar compounds in the drilling fluid compared to their concentration in the rock Cp> Cn by 0.25 mol/L makes it possible to increase the stability of the rocks around the wellbore compared to the initial conditions. Studies of lubricating additives showed that introducing 1.5-2.0% of FRW additive reduces the friction coefficient of the metal-metal pair in a clay solution by 70-75% and in an aqueous solution up to 65%. The findings suggest that drilling fluids developed at the Well Drilling Department of the St. Petersburg Mining University have a high potential for their application in oil and gas fields in order to improve the efficiency of drilling and completion of wells. It is also noted that the scientific and technical potential of the department allows for input control of reagents in drilling fluids, as well as the development and research of various compositions not only for drilling and completion of wells, but also for development and repair, which are applicable in real field conditions.