粒子射流耦合冲击破岩实验

Experiment of rock breaking by particle-jet coupling impact

为研究高速金属粒子和流体耦合冲击作用下岩石破碎的特性和规律,利用自主研制的粒子射流耦合冲击破岩实验装置,开展了射流速度、粒子直径与破岩效率实验,粒子体积分数与破岩效率实验,射流角度与破岩效率实验和粒子射流破岩与钻压比例关系等实验。研究表明:含有一定动能的高频粒子冲击更有利于提高破岩效率,粒子在钻井液中所占的体积分数直接反映了粒子破岩效果的好坏,实际钻井时可以利用单个粒子的冲击动能和单位岩石面积上受到粒子的冲击频率来确定粒子的掺入比例;研制粒子射流冲击钻头时,可以不采用0°入射角的射流喷嘴,而采用1个入射角为8°和3~4个入射角为20°喷嘴的组合设计,其更有利于提高粒子动能的利用率。

To study the characteristics and laws of rock breaking under the high-speed metal particle and fluid coupling impact,the self-developed experimental device for rock breaking by particle-jet coupling impact was utilized to carry out a series of experiments on jet velocity,particle diameter and rock breaking efficiency,particle volume percentage and rock breaking efficiency,jet angle and rock breaking efficiency and the proportional relations between drilling pressure and the rock breaking by particle jet.The results show that the impact of high-frequency particle with certain kinetic energy is more beneficial to improve the rock breaking efficiency.The volume fraction of particles in drilling fluid directly reflects the effect of rock breaking via particles.In practical drilling,the mixing ratio of particles can be determined by two parameters,i.e.,the impact kinetic energy of a single particle and the impact frequency of particle per unit area.When the particle jet impact bit is developed,it is suggested to adopt the combined design of one nozzle with the incident angle of 8° and 3-4 nozzles with the incident angle of 20°,rather than jet nozzles with the incident angle of 0°,which is more beneficial to improve the utilization rate of particle kinetic energy.