Academic literature on the topic 'Vibratory-Rotary drilling'

Abstract The article presents the design of the heading set of equipment for drivage of development galleries in rocks prone to gas-dynamic phenomena. This equipment can carry out the full technological cycle of rock excavation. The use of the P-110 roadheader of Ukrainian PJSC “Novokramatorskyi Machine Building Plant” with an operating device on a telescopic boom is offered for the aggregation of the heading set of equipment for underground development galleries drivage in emission-hazardous rocks. The device for mechanized boreholes drilling in an emission-hazardous coal seam has been devised based on the EBGP-1 M drilling machine of the Ukrainian SPA “Chervonyi Metalist Co Ltd”. This device is placed on the telescopic boom of the roadheader. For mechanized drilling of explosive, degassing, unloading and injection boreholes, a rock-breaking tool has been proposed that can perform an effective vibratory and rotary loading method of drilling in medium-hard and hard rocks. Safe methods for underground development galleries drivage in gas-bearing emissionhazardous rocks have been worked out. The effectiveness of these methods was determined in industrial conditions. It is possible to conclude that this new heading set of equipment and technology can be recommended for implementation in the mining coal industry.

Stick—slip-induced vibration in drilling has a detrimental effect on the drilling system and may lead to the failure of the drill string. This study is a further development of a friction-driven vibro-impact system which was investigated previously. The system used the stick—slip properties to generate a vibratory motion of a hammer that collides with the bit. The previous study focused on the influence of the friction on the response of the system without impacts. This paper investigates the full dynamic response of the model including friction and impact. Numerical bifurcation analysis of the system is undertaken to establish various motions and dynamical changes. This study focuses on the system performance outside the stable interval identified in the earlier investigation. The response of the system is illustrated along with the phase portraits.

Reducing vibrations in well drilling has a significant effect on improving the overall performance of the drilling process. Vibrations may affect the drilling process in different ways, i.e., reducing durability of the drillstring’s elements, reducing the rate of penetration, and deviating the drilling direction. In rotary drilling, which is used to open mine and oil wells, torsional vibration of the drillstring is an important component of the overall system’s vibration that has received less attention in the literature. In this paper, we propose a finite element model for a sample blasthole drillstring used to open mine wells to investigate its torsional vibrations. Boundary conditions and elements’ specifications are applied to this model. In the model, the interaction between the insert and the rock is represented by a set of repetitive impulses according to the insert pattern. The steady-state response of the system to the repetitive impulses is found and natural frequencies, kinetic energy, and potential energy of the drillstring are calculated. The root mean square (RMS) of the total energy can be used as the measure for reducing the torsional vibration of the system. Finally, an optimum combination of inserts on the cone’s rows was found based on minimizing the total vibratory energy of the drillstring. The optimum design can reduce the torsional vibrations of the drillstring and improve the drilling performance.