4.10 A well is being drilled at a vertical depth of 12,200 ft while circulating a 12-lbm/gal mud at a rate of 9 bbl/min when the well begins to flow. Fifteen bar- rels of mud are gained in the pit over a 5-minute period before the pump is stopped and the blowout preventers are closed. After the pressures stabil- ized, an initial drillpipe pressure of 400 psia and an initial casing pressure of 550 psia were recorded. The annular capacity opposite the 5-in., 19.5-lbf/ft drillpipe is 0.0775 bbl/ft. The annular capacity op- posite the 600 ft of 3-in. ID drill collars is 0.035 bbl/ft. Assume M-16 and T-600°R. d. Compute the pressure that will be observed at the casing depth of 4,000 ft when the top of the kick zone reaches the casing if the kick is circulated from the well before increasing the mud density. Answer: 3,198 psia. e. Compute the annular pressure that will be observed at the surface when the top of the kick zone reaches the surface if the kick is circulated to the surface before increasing the mud density. The annular capacity inside the casing is also 0.0775 bbl/ft. Answer: 1,204 psia. f. Compute the surface annular pressure that would be observed at the surface when the top of the kick zone reaches the surface if the mud density is increased to the kill mud density before circula- tion of the well. Answer: 1,029 psia.