Rock hardness gradients across layer interfaces strongly affectDTHdrill efficiency. From f=3 shale to f=9 quartzite, speed drops from 50 to 8cm/min in 10 seconds.
Drill pipe torque surges from 1500 to 3200N·m, risking tool jamming. Soft rock’s 350 impacts/min face 2-3s “frequency loss” at hard interfaces.
Hydraulic pressure needs over 22MPa to regain stability. 梯度 (>4f/m) cuts efficiency by 28% vs homogeneous rock.
Drill pipe fatigue damage risk triples here. Inspections should shorten to every 50 米.
邦欣钻机
