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Line 90: − − [[file:pressure-detection_fig3.png|thumb|left|{{figure number|3}}Electric logs of two wells offshore Louisiana. Well A had normal pressure. Well B, 2000 ft away and across a growth fault, showed a sudden decrease in resistivity of shale (increase in conductivity) at about 11,100 ft. Shortly thereafter, the well showed indications of an impending blowout. (After <ref name=Wallace_1965>Wallace, W. E., 1965, Abnormal subsurface pressures measured from conductivity or resistivity logs: The Log Analyst, v. 6, p. 26-38.</ref>.)]]
→Detection of overpressure while drilling
A rising level of mud in the tanks indicates that more mud is coming out of the hole than is going in. This is called a “kick.” This happens because formation fluids are entering the hole and the well is threatening to blow out. The situation is extremely serious, and proper steps must be taken to get the gas, oil, or water out of the hole. The most common method is to close the blowout preventers and stop the pumps. After a few minutes, the pressure at the top of the drill pipe will equal the pressure in the formation minus the weight of the column of mud. This is the excess pressure that must be balanced by increasing the mud weight. The pumps are then started to circulate the extraneous fluid out of the hole. The drill pipe pressure is carefully controlled with the choke. If the equilibrium drill pipe pressure is exceeded, the well may lose circulation, and if it is too low, the well will blow out.
A rising level of mud in the tanks indicates that more mud is coming out of the hole than is going in. This is called a “kick.” This happens because formation fluids are entering the hole and the well is threatening to blow out. The situation is extremely serious, and proper steps must be taken to get the gas, oil, or water out of the hole. The most common method is to close the blowout preventers and stop the pumps. After a few minutes, the pressure at the top of the drill pipe will equal the pressure in the formation minus the weight of the column of mud. This is the excess pressure that must be balanced by increasing the mud weight. The pumps are then started to circulate the extraneous fluid out of the hole. The drill pipe pressure is carefully controlled with the choke. If the equilibrium drill pipe pressure is exceeded, the well may lose circulation, and if it is too low, the well will blow out.
===Delayed indications===
===Delayed indications===