IWCF Level 2 Drilling cheat sheet

Hydrostatic pressure: HP (psi) = 0.052 × mud weight (ppg) × true vertical depth (ft). Use TVD, never measured depth, for pressure calculations.

Formation pressure is balanced when mud hydrostatic pressure equals pore pressure; overbalance means HP exceeds pore pressure, underbalance means HP is less and influx can enter.

Kill mud weight (ppg) = current mud weight + (SIDPP ÷ (0.052 × TVD)). SIDPP is shut-in drill pipe pressure read after stabilization.

Slow circulating rate pressure (SCR) is recorded with the bit off bottom at a low pump rate; it is the reference for all kill-sheet pressure calculations.

Initial circulating pressure (ICP) = SIDPP + SCR. Final circulating pressure (FCP) = kill mud weight ÷ old mud weight × SCR.

MAASP = (formation fracture pressure equivalent − current mud weight) × 0.052 × shoe TVD; it is the maximum surface pressure allowed with the well shut in.

Shut-in procedure: stop rotation, lift string off bottom, stop pumps, close BOP, then read and record SIDPP and SITP once pressures stabilize.

Kick indicators while drilling: flow with pumps off, pit volume gain, increase in flow rate or pump pressure drop, gas or oil shows, and reduced drill rate.

BOP stack components: annular preventer for stripping and closing on any shape, pipe rams for specific pipe sizes, blind/shear rams to close the open hole and shear pipe, and choke manifold for controlled flow.

Well intervention workover operations must maintain two independent barriers at all times; a single barrier is never acceptable during intervention.

Wireline lubricator length must exceed the maximum length of the toolstring so the tools can be fully housed before the well is opened.

Snubbing is used when wellbore pressure would push the pipe out of the hole; stripping is moving pipe through the BOP with pressure contained but not requiring snubbing force.

Coiled tubing fatigue is tracked by accumulated bending cycles; the string is retired when remaining life reaches the operator's limit.

Bullheading pumps fluid into the formation to displace wellbore fluids; it is used when circulation is impossible or when killing a gas well with a safe formation.

BOP test frequency for intervention: function test weekly, pressure test at specified intervals (commonly 14 or 21 days depending on operator policy) and after any seal repair.

Kill fluid density for intervention = current density + (SITHP ÷ (0.052 × TVD)); SITHP is shut-in tubing head pressure.

Hydraulic workover units use slips and a traveling snubbing jack to move pipe under pressure; the BOP stack must be rated above the maximum anticipated surface pressure.

Pressure testing of lubricator and intervention stack is done to the lower of MAASP or the rated working pressure of the weakest component.