Design and Experimental Study of Core Bit for Hard Rock Drilling in Deep-Sea

The hard rock stratum will seriously affect the efficiency of deep-sea drilling and greatly increase cost operations due to its complexity. In ocean operations, design bit is critical. Therefore, core should be able drill in a variety formations, especially stratum, with function reducing need change formation changes improving efficiency. this paper, three different bits were designed according seabed: roller bit, diamond bionic bit. According test results, it was observed that: (1) It fully proven that has characteristics stable strata, small torque high same method can realize shallow soft strata through setting parameters. (2) For field data show new formula good adaptability changing area, an average rate penetration (ROP) 4.4 m/h life 137.75 m. (3) experiment showed lithology gray green tuff, which had recovery up 100%. ROP 1.35 m/h, highest 1.88 m/h. kinds have effectively solved technical problem efficient hard-rock stratum.