中文摘要：

射流喷嘴是径向水平井技术中的关键部件,其破岩能力直接影响水平井眼的延伸能力和钻进速度。在多孔喷嘴的基础上,设计脉冲空化多孔喷嘴,分析其脉冲空化射流的调制机制,并通过试验与多孔喷嘴的破岩效果进行对比。结果表明：脉冲空化多孔喷嘴破岩效果优于多孔喷嘴,孔眼深度是多孔喷嘴的1.02~2.18倍,破岩体积是多孔喷嘴的1.23~2.35倍;为保证喷嘴破岩形成的最小孔眼直径大于喷嘴外径,试验岩样的喷嘴压降不能小于30 MPa;射流喷嘴破岩存在最优喷距,试验条件下的最优喷距为12 mm;利用脉冲空化多孔喷嘴可增加径向井的水平延伸长度,提高钻进速度。

英文摘要：

Jet nozzle is a key device in radial horizontal well drilling technique,of which the rock breaking ability directly affects the extension of horizontal holes and drilling rate. On the basis of the multi-hole nozzle,a pulsed cavitating multi-hole nozzle was designed,and its modulation mechanism of pulsed cavitating jet was analyzed. Also,the rock breaking test was carried out to compare with the rock breaking result of pulsed cavitating multi-hole nozzle. The results indicate that the rock breaking result of pulsed cavitating multi-hole nozzle is better than that of multi-hole nozzle. The hole depth from pulsed cavitating multi-hole nozzle is 1. 02-2. 18 times than that from multi-hole nozzle. The rock breaking volume from pulsed cavitating multi-hole nozzle is 1. 23-2. 35 times than that from multi-hole nozzle. To guarantee the minimum hole diameter is bigger than nozzle diameter,jet impact pressure should not be lower than 30 MPa in the experiment. There is an optimal standoff distance in the bock breaking,which is 12 mm under the current testing conditions. The results suggest that using pulsed cavitating multi-hole nozzle can increase the extension of horizontal holes and improve drilling rate in radial drilling technique.