This paper is devoted to the history of exploration of sintezed and natural gas hydrate. Academic, engineering and energy periods of the history of gas hydrates studies are described. The most significant researches in this area are described. The main practical projects in the world for the study and production of gas hydrates are reviewed.

ВплиВ Витрати промиВальної рідини на контактну температуру при бурінні сВердлоВинPurpose. To establish the influence of drilling fluid circulation rate onto the contact temperature during the rotation drilling using an impregnated diamond drill bit; to verify the mathematical model of the diamond drill bit heating process in the course of boreholes drilling.Methodology. Bench experiments and theoretical analysis using methods of mathematical modeling. Findings. In the course of the bench experiments the data of influence of the drilling fluid circulation rate on the contact temperature during drilling of granite rock with a 59-mm diameter drill bit were obtained. A relevant mathematical model of the drill bit heating under the variable rate of drilling fluid was represented on the basis of a system of the heat transfer differential equations. A comparative analysis of experimental and predicted data was carried out, and its findings positively confirm the reliability of the mathematical modeling of heat transfer processes in the downhole during bore-hole drilling.Originality. The methodology of experimental measuring of the contact temperature during the bench experiment borehole drilling using resistance sensors was proposed herein. New experimental data was obtained which allowed establishing a correlation between the contact temperature and the rate of drilling fluid in the downhole area. The proposed mathematical model of the process is found to be adequate; it allows predicting the temperature mode on the working face of borehole in the course of drilling. The findings of the research make it possible to substantiate the effect of the diamond core drilling performance gaining due to transition from the fixed time operation parameters to the variable ones.Practical value. The regularities of action of the drilling fluid circulation rate on the contact temperature of the "tool -working face" system in the course of borehole drilling were established. The performed research confirmed the possibility of managing the thermal mode of drilling by variation of the drilling fluid circulation rate. The diamond core drilling performance gains, therefore, are possible to achieve by way of increasing the thermal stimulation of the mining rock. The developed mathematical model allows forecasting the contact temperature in the course of borehole drilling for various values of the drilling fluid circulation rates. Using of this model makes it possible to define the permissible diminishing of the drilling fluid circulation rate in order to prevent any abnormal thermophysical wear of the drill bit.Keywords

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Purpose. To study the impact of pulse flushing on the power consumption of rock decomposition during diamond core drilling.Methods. Theoretical analysis, processing of the obtained experimental data.Findings. The decrease in power consumption of rock decomposition process during drilling with jet pulse flushing was studied. The influence of the bottom-hole power and jet pulse flushing parameters on the efficiency of rock decomposition process was investigated. Physical mechanisms of mining rock degradation under the jet pulse flushing were considered in the article.Originality. It was established that the drilling performance is growing along with increasing of pauses between the flushing liquid supply intervals. At that, the relative reduction of energy consumption of the rock decomposition process is increasing when the bottom-hole power is decreasing. The study provides theoretical grounds for the increase in the mechanical rate of drilling during the jet pulse flushing owing to utilization of the generated frictional thermal energy in the bottom-hole. It is demonstrated that using pulse flushing intensifies the processes of thermal cycling degradation of the mining rock. Practical implications.It is demonstrated that the pulse flushing mode has a potential to improve the performance of diamond core drilling. The outcomes of the research can be useful for grounding the specifications of the jet pulse flushing method during the development of the energy saving modes of diamond core drilling processes.

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