Development and Field Test of a Non-Planar Cutter PDC Bit with Convex Ridges

When conventional PDC bits are used to drill into the massive gravel layer at the Kuqa Piedmont, challenges such as low rock breaking efficiency, low ROP and long drilling cycle are encountered. A deeper analysis concluded that the large impact of gravels on the planar tooth of conventional PDC bits, as well as the further tooth breakage or severe wear are the main reasons of low penetration rate. Therefore, a convex ridge non-planar cutter was designed, and the matched PDC bit was developed to transform the traditional face cutting into linear fracturing and face crushing methods, which greatly improves the rock breaking efficiency of bit. The lab tests suggest that the convex ridge non-planar cutter had good impact resistance and anti-abrasive performance, and the impact resistance was 10 times that of the planar tooth. Two convex ridge non-planar tooth PDC bits have been tested in the gravel interval of a well in the Bozi Block, creating a record of the highest ROP and the longest single bit footage in this block. Compared with the conventional PDC bits in adjacent wells, the footage was increased by more than 1.5 times, and the average ROP increased over 64%, with obvious effect of raising the penetration rate. Research and tests indicated that the ridge non-planar cutter PDC bit could meet the requirements of drilling in the massive gravel layer of Kuqa Piedmont effectively, and provide technical supports for the efficient exploration & development of deep natural gas in this area.