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.

Ecologically safe penetration into the subglacial Lake Vostok discovered in the depth of 3,700 m in East Antarctica (more than 10,000 km2 , hypothetically freshwater and containing relict life forms) requires development of new methods, technologies and technical means of drilling.

Born in ancient times, drilling wells until the second half of the 19th century remained mostly percussive on rope or rods. Rotary drilling was only manual and was used for sinking shallow wells in weakly cohesive rocks. As far back as 600 years B.C. Confucius wrote of thousands of wells as deep as 500 m and even as deep as 1,200 m drilled in China for water and salt. Over the centuries this ancient invention of the Chinese has hardly changed. French travelers of the 19th century described Chinese drilling technology as it was more than 2.5 thousand years ago.

The energy intensity of fusion ice drilling is many times higher than that of mechanical destruction. A significant advantage of the fusion ice drilling method is the simplicity of design and reliability of thermoelectric drilling shells on a load-carrying cable, so they have been widely used in the domestic practice of studying glaciers and ice sheets with the help of deep boreholes and allowed to achieve record results.

Deep drilling of ice deposits in the Arctic and Antarctic is carried out mainly by electromechanical and electrothermal drilling shells on a load-carrying cable.

At present, a variety of physical methods of breaking or de-strengthening rocks are increasingly being introduced into the practice of drilling.

The fruitful activity of Academician D. V. Nalivkin is inextricably linked with such a milestone event in the history of the Soviet geological service as the creation of the geological map of the USSR. Although this did not exhaust the tasks of geological mapping, still the problem of erasing "blank spots" began to lose its acuteness. In the foreground came the tasks of improving the efficiency of geological exploration, in the solution of which the geological map has acquired the role of a kind of compass, helping to determine the direction of prospecting and exploration work.

Flushing fluid flow rate is as important a parameter of the drilling mode as axial load and rotational speed of the drilling tool.

The development of diamond drilling technology based on the use of high-speed modes, new rock-destroying tools and the use of low-heat-capacity cleaning agents (gas-liquid systems) makes increased demands on the performance and, first of all, on the normalization of the temperature regime of diamond rock-destroying tools.

The main indicator characterizing the drilling-melting process is the drilling speed. At thermal method of drilling speed is a generalizing indicator, depending on the power supplied to the crown-heater, axial load, geometric shape of the crown, the conditions of removal of fracture products, from the thermophysical properties of the material from which the crown is made, and the properties of the melted rock (ice) ...

Foam is one of the varieties of flushing agents, especially promising when drilling wells in complicated conditions. Practical development of this affective technological means requires a well-founded by calculations selection of pumping and compressor equipment, design of rational modes of circulation ...

Development of a high-performance thermodrill for high-speed sinking of "dry" wells with coring in snow and firn and ice deposits, based on the use of water vapor as an intermediate coolant on the principle of "open" steam tube, causes the necessity to find an analytical expression of the complex heat exchange between condensing steam and the ice face taking into account the shielding effect of the condensate film with thickness e inside the hollow annular condenser and the layer of melt water with thickness S, continuously formed under its working face during the drilling-melting process...

Thermal method of drilling through snow and firn and ice deposits in hard-to-reach areas has a number of advantages over conventional mechanical drilling methods. It does not require heavy equipment and large energy costs, provides high quality and 100% core yield, which can be used for a wide range of studies: glaciological, petrographic, crystallomorphological, geochemical, etc. ....

With the increase of drilling depths at present up to 6-7 thousand meters, and in the foreseeable future up to 10-15 thousand meters, the temperature factor becomes more and more serious. ...

The first solutions to the problem of drilling with simultaneous freezing of passable rocks, which is reduced to finding the relationship between the depth of the freezing front and the mechanical speed of drilling, are approximate and contain parameters determined from “experience" or arbitrarily.

The regularities of the temperature regime of boreholes and mine workings, especially in conditions of changes in the aggregate state of the surrounding rocks, are described by extremely complex analytical expressions. The concepts of the coefficient of unsteady heat exchange k_τ and the coefficient of heat exchange intensification at the aggregate transition k_agr.

Permafrost is spread on the area of about 49.7% of the USSR territory. Drilling of boreholes in frozen rocks is connected with a number of specific difficulties. Weakly bound loose Quaternary sediments, as well as destroyed bedrock cemented in the frozen state by ice, are very sensitive to violation of their temperature state. When ice thaws, such rocks lose cohesion and stability and may become fluid. Any frozen rocks, including monolithic and stable rocks, are accumulators of huge reserves of cold, which also significantly complicates the processes of conducting wells.

The purpose of simultaneous with the drilling process of freezing of passed melted rocks is to ensure their monolithicity and strength, which makes it possible to avoid complications associated with the instability of loose wet rocks, and to obtain a high core yield.

Due to increasing depths and intensification of drilling processes there is a practical necessity to take into account thermal phenomena in drilling wells. The temperature of the flushing medium becomes one of the main factors determining the success of drilling operations.

The most important task of exploratory core drilling is to ensure high yield and quality of core - source material for geological and engineering-geological sampling. Analysis of production data of a number of organizations engaged in drilling in permafrost rocks shows that when drilling with flushing the core yield is 60-70% for bedrock with moisture content of 2 - 5% and 20-30% in rocks with moisture content of 15% and more. In production conditions very often in order to increase the core yield one switches to “dry” drilling. However, the core quality deteriorates sharply. Partial or complete thawing of the core takes place with violation of its structural characteristicsю

Quantitative determination of the free fall velocity of a gel in a liquid or gaseous medium is of paramount importance in the theory of hydraulic and pneumatic transport, gravitational methods of enrichment, for the calculation of a number of apparatuses, machines, technological processes and, in particular, is the basis for calculating the required flow rate of liquid or gaseous flushing agent for the removal of cuttings when drilling wells.At free fall in the medium, the body reaches a finite velocity when the resistance force of the medium becomes equal to the driving force of the weight of the body in the medium.