Near-Bit Torsion Impactor and Its Testing Applications in Jinyue 7-1 Well

In order to solve the problems of slow speed and high cost in deep well drilling, the influence of the "stick-slip vibration" on the PDC bit should be suppressed and the efficiency of rock breaking in deep formation should be improved. Based on the analysis of drilling condition of PDC bit, Near-bit Torsion Impactor as a new drilling speed tool is proposed. The tool can transform part of the hydraulic energy of the drilling fluid into high-frequency and circumferential vibration, and acts on the PDC bit directly, which can make the BHA move smoothly and suppress the impact that the "stick-slip vibration" have on the PDC bit effectively. At the same time, the high-frequency vibration shock can increase the rock breaking efficiency of the PDC bit. In the test of Jinyue7-1 well in the Tarim Oilfield, Near-bit Torsion Impactor operates stably, and the speed effect reaches international advanced level. Compared with the screw drill, the average ROP is increased by 42%. And it is more obvious in hard mudstone, where the ROP is increased by 88%. The experimental results show that the Near-bit Torsion Impactor has a good effect on the acceleration of speed in the deep well drilling.