Well kill: kill mud weight and circulating pressures
Kill mud weight from the shut-in drill pipe pressure, and the initial and final circulating pressures for the driller's and the wait-and-weight methods.
ρ_kill = ρ + P_dp / (g · H) + ΔρP_ic = P_scr + P_dpP_fc = P_scr · ρ_kill / ρThe kill mud balances the formation pressure: ρ_kill · g · H = ρ · g · H + P_dp. Add the margin Δρ your rig's procedures require; the casing pressure is not part of the calculation.
Source: IWCF/IADC well control: driller's method, wait-and-weight method
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
The stabilised standpipe pressure after the well is shut in.
Recorded in advance at the kill rate (usually 1/3–1/2 of the drilling rate).
As the well control plan requires; 0 balances the formation pressure exactly.
Unit converter for this formulaDensity and °API · Pressure · Length
- kg/m³850
- g/cm³0.85
- t/m³0.85
- rel. (water 4 °C)0.850024
- lb/ft³53.0638
- lb/gal (ppg)7.09359
- SG (60/60 °F)0.850837
- °API34.8068
°API and SG refer to the density at 60 °F (15.6 °C) relative to water at 60 °F, relative density to water at 4 °C. The oil's thermal expansion between the measurement temperatures is not included. °API = 141.5 / SG − 131.5.
- P_ic — Initial circulating pressure (ICP)–
- P_fc — Final circulating pressure (FCP)–
- P_p — Formation pressure–
More in Pressures and drilling fluid
Pressure of a column of drilling or kill fluid at a true vertical depth, and its gradient (equivalent density).
Equivalent density of the pore pressure and the mud weight that keeps the hydrostatic pressure above it by the margin of the Kazakhstan industrial safety rules (item 85-2), with the depth-dependent cap on the overbalance.
The density equivalent to the bottomhole (or shoe) pressure while circulating: the static mud column plus the annular friction loss above that point.
Fracture (leak-off) equivalent density and pressure at the shoe from a LOT or FIT, and the maximum allowable annular surface pressure (MAASP) for the current mud weight.
How much weighting material (barite, hematite, calcium carbonate), water or another fluid to add to bring the mud to the required density, and the final volume.
Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.