... , Oil exploration and hydrapower station grouting project ( wireline core drilling and double-tube core drilling)We produce a wide range of drilling ... (AQ-PQ) and assemblies, synthetic diamond core bits, natural diamond surface-set core bit, PDC bits (core or noncoring), casing shoes, reaming shells ... and BW, NW, HW casing tube: BW, NW, HW, HWT2.Core barrel: BQ,NQ,HQ,PQ , head assembly and assembly 3 ...