Research On Hydraulic Pulsed Driving Axial Vibration Drilling Method And Test

Improving rate of penetration and reducing cost are always essential to drilling practice.With the proportion of deep wells,extended reach wells and horizontal wells increasing,the low weight transfer efficiency can greatly reduce ROP.Extra impact force can be exerted on drill bit with the combination of hydraulic pulsed jet and downholeaxial vibration effect.In this way,friction force during drilling extended reach wells and horizontal wells can be reduced effectively.A new drilling method using hydraulic pulsed pressure to drive the drill pipe’s axial vibration is proposed.The hydraulic pulsed jet technique and axial vibration friction reduction technology are combined in order to improve drilling speed and weight transfer,thus increasing the extension of horizontal well limit.Hydraulic pulsed jet driving axial vibration drilling tool is designed and studied through CFD numerical simulation.The tool’s pulsed pressure fluctuation characteristics are analyzed,and the effects of flow rate on pulsed pressure amplitude,pressure drop,etc.are obtained.Also,important factors including the number of impeller blades,the through-hole area of pressure-bearing surface are analyzed.Transfer function model and state space model for calculating tool’s axial vibration displacement are established.Moreover,the attenuation characteristics of pressure fluctuation amplitude are analyzed.Additionally,hydraulic parameters design for hydraulic pulsed jet driving axial vibration drilling technique is put forward.Based on the structural design and numerical simulation,Φ127 mm and Φ178 mm experimental prototypes are manufactured and tested.The effects of flow rate on pulsed pressure frequency,pressure fluctuation amplitude,pressure drop,axial vibration displacement,etc.are obtained.Preliminary field test shows that the tool functions well and is capable of enhancing the ROP.The test results provide basis for the optimization of hydraulic pulsed jet driving axial vibration drilling tool and subsequent field application.