A “kick” occurs when the formation pore pressure gradient (associated with the formation’s oil, water and/or gas) exceeds the mud pressure gradient. Gases tend to expand quickly as they escape from a high pressure zone.
Warning signs of an impending kick:
(1) a change in the flow rate of surface fluids including mud
(2) change (increase or decrease) in pump pressures
(3) change (increase or decrease) in the rate of drilling
(4) decrease in apparent drill pipe weight
(5) presence of gas, oil and/or water in the mud around the drill hole
(6) presence of gas in the mudlogging unit
The presence of one or more of these signs does not mean that a well kick will occur, but preventive steps still need to be taken until the operators feel that it is safe to return to drilling.
