One of the most common types of geological complications arising when drilling wells through permafrost rocks is the violation of wellbore integrity due to changes in the natural stress state of the surrounding massif. Securing the wellbore walls with casing requires switching to a smaller drilling diameter, and the use of grouting materials for grouting fractured rocks is ineffective, since cracks are usually filled with ice, preventing the penetration of grouting material into them.
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.
