SoMe feaTureS of DrillinG TeChnoloGY wiTh PDC BiTS Purpose. Improving the technology of drilling wells with blade bits by establishing patterns of interaction in a pair of "cutter rock" to find out the causes the "hanging" blade bits over the central part of the bottom hole and develop recommendations for eliminating. Methodology. The tasks were solved by a comprehensive research method, which includes analysis and synthesis of literature and patent sources, analytical studies of existing rotary drilling models to solve the problem of "hanging" of the blade bit. findings. It has been established that the distribution of axial load on rock cutting elements depending on the distance from the center of the blade bits is extremely uneven: the incisors located on the periphery of the bit edges experience the smallest load, and the incisors located in the central part of the bit are the most stressed. originality. It was shown for the first time that the "hanging" of the bit over the central part of the face is caused by the redis tribution of axial load along the bit blades from the minimum value at the periphery of the blades to its sharp increase to the bit axis to compensate for the decrease in the path travelled by the bit in this zone. For the first time, it was proposed to perform blade bits with sharpened blades along a radius, and to destroy the resulting core with a special device. Practical value. As a result of the research, recommendations have been developed for the design of a fundamentally new design of the blade bit, which will not "hang" over the central part of the face during the drilling process. This design of the blade bit can reduce the energy intensity of drilling.
The work is devoted to the calculation of the main technological parameters of a bit of a new patented design, the essence of which is to replace worn out working elements (carbide cutters or diamond-containing matrices) during drilling with a new, not blunt tool right at the bottom of the well. The need to correct the calculation method is associated with the design feature of the new crown, which consists in the fact that when using it, an annular bottom of a larger width is formed compared to serial crowns of the same outer diameter. Therefore, the known formulas for carbide and diamond drilling have been supplemented with appropriate correction values so that the ROPs when using new and serial bits are the same during full development. So, when using carbide cutters as rock-cutting elements, a correction factor is introduced that increases the number of main cutters in the crown sectors of the first and second stages. In diamond cutting, it is necessary to increase the maximum speed of the tool, taking into account the mining technical conditions of penetration. Refined formulas for calculating the parameters of the drilling mode allow preserving the advantages of bits with extendable working elements and increasing the drilling speed by 1.7-1.8 times compared to existing serial bits.
The work is devoted to the study of the effect of powdered WC monocarbide of different grain sizes, introduced into the composition of the binder of diamond grains of the composition 94 WC + 6Co + Cu in the manufacture of a diamond-bearing matrix of BS�NQ drill bits with a diameter of 75.6 mm, designed by ISM (Ukraine). The effectiveness of the mentioned crowns was evaluated according to the proposed indicator F= ( - mechanical drilling speed; h � the value of the deepening per single experience, � � linear wear of the matrix in height). Experimental drilling on granite blocks showed that with an increase in grain size from 80/63 to 200/600, the efficiency index increased by 1.9 times, and an increase in the percentage of monocarbide from 6% to 12% increased the F value by 10-12%. A further increase in grain size up to 250/200 caused a sharp decrease in the mentioned F index.
It has been theoretically and experimentally shown that the use of a "comb" profile of the working end of the matrix in the design significantly (by 2 times) increases the rate of destruction of the face in comparison with a rectangular end.
To further increase the efficiency of working on the destruction of the face, it is necessary to create diamond crowns, the matrix of which in height consists of several impregnated layers with a comb profile, separated from each other by layers of material of lower hardness (for example, VK-20).
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