In spite of the certain success in ice drilling technology, there are enough accident examples of the deep coring in so-called warm ice, which is characterized by the increasing of ice crystals and has temperatures closed to the pressure melting point. The generally accepted recommendations for choosing of rational drilling parameters in such ice don’t exist. The low reliability of the drilling process as often as not resulted to the one of the most severe accident in the hole – sticking of the core drills. The effective accident elimination is possible due to the ice dissolving in the sticking zone by the delivery in this zone of the solvent active to ice, for example, ethylene glycol or its aqueous solution.
In order to drill "dry" wells in snow-firn and ice strata, the SPbSMI (TU) Department of Drilling Technology and Technology is developing a technology of mechanical drilling with bottom-hole air circulation to remove cuttings. The electromechanical drilling tool for drilling with bottom-hole air blowout is similar to the previously developed KEMS-112* drilling tool for drilling deep wells filled with filling fluid.
The primary results of the research and engineering work of the Department of Technology and Technique of Well Drilling, carried out and completed in 2000, are presented. The main result of drilling long wells in the ice of Antarctica is the development of the project of environmentally safe opening of the subglacial Lake Vostok, a unique natural phenomenon, the complex study of which is of the greatest interest to the world scientific community. A 505 m long well with full core recovery was drilled on the Academy of Sciences glacier (Severnaya Zemlya archipelago) in the framework of the international environmental program PEGAIS. Geophysical measurements were carried out in the well. A new method of tubeless casing and sealing of anomalous intervals using a fusible binding material and a thermal plugging penetrator was developed. Basic theoretical and technological principles of liquidation plugging of hydrogeological wells with the use of economical and environmentally safe cementing mortar based on cheap mineral waste were developed. Effectively conducted research and experimental developments on the combined heat and hydrodynamic effects on low-productive sands to increase oil and gas production wells, clarified the laws of the hydro and foam core. New applied programs for PC were formed, allowing to increase adequacy of data and to expand the field of application in evaluation of regulation and stabilization of circulation and heat exchange processes during well sinking and development.
