PRACTICE AND KNOWLEDGE ON THE WIRE-LINE CORING FOR COAL DRILLING

Based on producing and practising,some knowledge about the question of rope coring technology,well structure,types of bits,coal cuttings coring,well protection,drill equipment matching and so on in coalfield drilling are presented in this paper.Including well diameter determination,drill stem equipment matching,well structure,protective casing; bit sizes selecting,matrix material; powder coal bits,cuttings corer,automatic-locking half-close tube;types of drilling fluids,pluging a hole with drilling or halting technology; and the use of adding the length of core barrel,pipe joint,tiltproof joint and separable fishing lance.