IWCF Level 3 DWC cheat sheet
IWCF Level 3 DWC · Keep the key ideas within reach.
Drilling Well Control
Hydrostatic pressure (psi) = 0.052 × mud weight (ppg) × true vertical depth (ft). Use TVD, never measured depth, for all pressure calculations.
Formation pressure (psi) = hydrostatic pressure of the fluid that balances the pore pressure; pore pressure gradient in psi/ft = pressure ÷ TVD.
Kill mud weight (ppg) = original mud weight + (SIDPP ÷ (0.052 × TVD)). SIDPP is shut-in drill pipe pressure read after stabilization.
Initial circulating pressure (ICP) = slow circulating rate pressure (SCR/SCRP) + SIDPP. Final circulating pressure (FCP) = SCR × (kill mud weight ÷ original mud weight).
Slow circulating pressure must be recorded at a defined low pump rate (commonly 30–40 strokes per minute) before drilling into a zone, because it is the friction component used in every kill calculation.
MAASP (psi) = (maximum allowable mud weight − current mud weight) × 0.052 × TVD of the shoe. It falls as mud weight rises and must be recalculated after every weight-up.
Kick indicators while drilling: flow with pumps off, pit gain, increased return flow rate, rising SIDPP/SICP, reduced pump pressure with unchanged SPM, and gas or saltwater shows.
Driller's method: circulate the influx out at the original mud weight holding casing pressure constant, then weight up and circulate kill mud holding drill pipe pressure on the FCP schedule. Wait and weight: weight up first, then circulate out the influx while pumping kill mud.
Shut-in sequence for a kick: stop rotation, stop pumps, raise the kelly/string to shut-in position, close the BOP (annular or ram), then open the choke and read and record SIDPP, SICP, pit gain and pump strokes.