Result

All of these relations assume true vertical depth, not measured depth — using along-hole depth in a deviated well overstates hydrostatic pressure and is a classic and dangerous error. Kill mud weight from shut-in drill pipe pressure assumes a stabilised reading with the drill string full of known-weight mud; a plugged float, trapped pressure or gas in the string invalidates it. The barite formula assumes barite of about 4.2 specific gravity and ignores any dilution or chemical treatment, so pit space and mud properties should be checked before weighting up. Equivalent circulating density here uses only annular friction and excludes cuttings loading and surge or swab effects, all of which raise downhole pressure further. The leak-off-derived maximum is the pressure the formation took at the shoe on that day and does not guarantee the same strength later or elsewhere in the open hole. Treat the drilling window as an indication and always work from the well-specific kill sheet, current pressure data and your certified well-control procedures.