Drilling Experiments of Teeth-shaped PDC Bit in Shenjingzi Oil Shale Mining Area of Song Liao Basin

Abstract:

There are often dozens of layers of dolomite body or bands embedded in oil shale formation in Qingshankou and Nenjiang group at Song Liao basin. While drilling in above mentioned oil shale formations, dolomite interlayers with relatively high hardness were often encountered. If ordinary tungsten carbide cutter drilling bit was used, not only the footage was too slow in drilling process, but also the bit was seriously damaged. To solve above drilling problems, the development of new drilling bit with high wear resistance and high penetration ability was eagerly needed. In this paper, a new type of teeth-shaped PDC bit was designed and manufactured. Field drilling experiments using these teeth-shaped PDC bits were conducted and their drilling performances were compared with those of tungsten carbide bits. The results indicated that the new teeth-shaped PDC bit demonstrated high rate of penetration, high wear resistance and long service life while drilling in oil shale formation containing dolomite interlayer. The technical and economical index of teeth-shaped PDC drill bit was better than that of conventional tungsten carbide cutter bits.