A FIELD TESTING OF MEDIUM SPEED SCREW DRILL TOOL COMBINED WITH DBS PDC BIT WITH STEEL MATRIX

The field test of 5LZ172-7. 0 medium speed positive displacement drills combined with XJ-DBS PDC bit was conducted in the vertical section of well No. G 2074in Xiaoguai oil field, Karamayi, Xinjiang. The test started from depth 2391. 4m and ended at 2937. 8m with drilling time of 69. 18h and an average ROP of 7. 90m/h, 116% higher than that of roller bit. In interval 2391. 4~2485. 96m the footage was 94. 56m with drilling time of 19. 75h and an average ROP of 4. 79m/h only. To increase ROP, 3m section chosen from 419. 05m to 2428. 62m was tested for drilling with rotary table combined with positive displacement drills. Following two results were gained:it facllitates the prevention of drilling assembly from stlcking in the borehole wall and ROP can be increased significantly.While drilling in interval 2485. 96~2937. 80m, the average ROP increased from 4. 79m/hto 9. 14m/h.