Analysis And Experiment Of Breaking Rock Process Under Two-way Rotary Condition

Shallow resources are becoming increasingly scarce,and energy exploration and exploitation are gradually moving deeper and deeper,which is the future development trend.In the process of drilling,the length of the drill string increases with the depth of the hole,and the rotating torque increases.The probability of early damage increases,which easily leads to accidents in the well.For this reason,the research group puts forward the principle of self-balancing drilling.The drilling tool adopts the "double-bit" drilling mode,eliminating the ground drill and the drill pipe in the hole,thereby eliminating the reverse torque produced by the rotary drilling of the drill string and its harm.The two-way rotary rock fragmentation of the double-bit can reduce the disturbance of the drill bit to the hole wall,thereby improving the comprehensive efficiency of drilling.On the basis of previous research,this paper studies the rock breaking process of single bit and double bit,studies how to improve the performance of double bit from bit tooth structure and matrix material,and compares the disturbance of single bit and double bit to formation.The main research contents and conclusions are as follows:(1)The rock fragmentation process of the bit under the condition of bidirectional rotation is analyzed.The rock contacted with the bit and the bottom of the hole is taken as the research object,and the theoretical calculation and simulation analysis are carried out.It is concluded that the twin bits rotate inversely with balanced torque near the bit,and the upper drill tool does not rotate,and is only subject to tension and pressure,thus avoiding the continuous disturbance of the drill tool to the hole wall.(2)The influence of teeth structure of impregnated diamond bit on its rock fragmentation performance was studied.The influence of teeth width and thickness of impregnated diamond bit on its rock fragmentation performance was mainly studied by means of software simulation and experiment.It is concluded that when the average tooth width of impregnated diamond bits is 14.42 mm and the tooth thickness is 5 mm,the rock-breaking effect of impregnated diamond bits is better through specific matrix matrix material formula for hard granite.(3)The influence of low temperature impregnating metal formula on the comprehensive performance of drill bit was studied.By preparing low temperature impregnating metal formula containing Sn and Ga,the low temperature impregnating formula which can reduce the sintering temperature of drill bit,improve the control ability of matrix material to diamond and improve the overall performance of drill bit was optimized.The results of experimental study and morphology observation show that the sintering temperature of low temperature impregnated alloys made of low temperature metals and conventional copper alloys decreases by 120 C when the low temperature metals account for 3 wt% of the mass of copper alloys,and the comprehensive properties of the matrix are greatly improved.The hardness,flexural strength and wear resistance of the matrix are increased by 36%,28% and 41%.At the same time,the wettability of impregnated metal to skeleton materials and diamond particles is increased,and the control ability of matrix to diamond is improved.The drill bit's penetration rate and service life are increased by 5% and 5% respectively.(4)The experiment of rock breaking process with inner and outer double drill bits was carried out.Through the laboratory test of single and double bit drilling in the complex artificial formation,the surface morphology of the hole wall was observed,and the preliminary conclusion was drawn: the double-bit bidirectional rotary drilling caused less disturbance to the formation than the single bit.Through the single and double bit tests and the study of matrix materials,this paper clarifies the two-way rotary rock breaking process,effectively improves the drilling speed and working life of the bit,and lays a solid theoretical foundation for further research and application of the follow-up self-balancing double-bit drilling system.