Design of Individuation PDC Bit and its Application in Santanghu Basin Vocanics

Niudong and Malang area in Santanghu Basin is a typical reservoir of volcanics, there are basalt layers with the thickness from hundreds to thousands meters under Permian, so the drill ability of which was bad, choice of bit was limited, and the drilling speed was very low, these factors constrainted premium and rapid drilling seriously. The core samples and well log information were used to analyze the formation litho logy of this area, the results demonstrated that the average drill ability level of the layer was 6, the highest was 8, and the layer was belong to medium hard rock. JP169-9M432 81/2"PDC bit was designed by using minor diameter and thick cutting tooth which were Φ13.44 × 10 mm and the thickness of diamond was 2 mm, with the disposition of nine asymmetry spiral blades, superficial inner cone, and three stops type of crown profile and high density mode, optimizing the hydraulic compositions of bits through hydraulic wash mechanisation and hydraulic recoil mechanics about PDC bits adopting gage gauge figure. Field application of the new bit demonstrated that the penetration rate (ROP) has been increased by about 16 percents compared with the average ROP in volcanic layer of Malang area, increased by about 56 percents compared with the cone bit, and increased by more than 5 percents compared with the earlier test PDC bits.