Structural Design and Test of ROP Improving Tool with Adjustable Impact Frequency
Rocks below the Permian are less drillable,leading to low rate of penetration(ROP),which can hardly be improved by only applying the drilling tool with single impact frequency.In this study,a ROP improving tool with adjustable impact frequency was developed.This tool uses drilling fluid as the power source to achieve im-pact function,and can change the impact frequency by changing the number of axisymmetric holes on the lower core.Based on the structural characteristics and working principle of the tool,the impact force generated during the impact process of the hammer was determined,and a single cutter rock-breaking simulation model was built for dy-namic simulation analysis.The simulation results show that as the impact frequency increases,the ROP and the maximum principal stress inside the rock tend to increase,but decrease when the impact frequency exceeds a cer-tain level.In the course of drilling hard formations such as granite,the optimal impact frequency is 18 Hz;in the course of drilling medium-hard formations such as sandstone,the optimal impact frequency is 16 Hz.Moreover,the principle of the tool was verified through field test.When the tool was used to drill in hard and medium-hard formations,the ROP was increased by 103.2%and 27.0%respectively compared with adjacent wells.The conclu-sions provide reference for further optimization and field application of the ROP improving tool with adjustable im-pact frequency.
rate of penetrationimpact frequencyPDC cutterdesign parameterfield application
NETL
NSTL
万方数据
维普
