Annular Pressure Loss
refer to pressure drop that occurs as drilling fluid circulates through the annular space between the drill pipe and the wellbore or casing.
$$ APL = \frac{1.4327 \times 10^{-7} \times MW \times L \times V^2}{D_h - D_p} $$
Go CalculationCritical RPM
The critical RPM is the speed at limit that drill string are rotated, vibration can happen to cause failure in drilling equipment if overun the critical RPM.
$$ N_{cr} = \frac{33055 \times \sqrt{ D_{p_o}^2 + D_{p_i}^2} }{L^2} $$
Go CalculationECD Engineering
This formula is applied for complex calculation of annular pressure loss and equivalent circulating density.
$$ ECD = \frac{P_s}{0.052 \times TVD} + MW $$
Go Calculation