Work out drilling rate of penetration instantly with clear inputs, formula shown and shareable results.
Rate of penetration rises roughly in proportion to weight on bit and rotary speed and falls with bit diameter. Mechanical specific energy — the energy consumed per unit volume of rock removed — is the diagnostic that shows whether extra weight and speed are actually being converted into hole or wasted in vibration and bit wear.
Rate of penetration
ROP = K x WOB x RPM / bit diameter
Drilling efficiency
MSE = 4 WOB / (pi d^2) + 480 x RPM x torque / (pi d^2 x ROP)
Drilling parameters must be set within the bit manufacturer's and bottom-hole assembly limits and the well's mechanical constraints. Exceeding them risks downhole tool failure and well control incidents.
Bit tooth founder — beyond a limit the cuttings cannot clear, the bit balls up or the teeth fail. MSE rises sharply at that point, which is the signal to stop adding weight.
Bit and bottom-hole assembly vibration, particularly stick-slip and whirl, which destroy bits and downhole tools. Drilling dynamics monitoring finds the safe window.