Patent ID: 7401654

Claim:
In a system comprising: a blowout preventer (BOP) having an upper end and a wellhead end, having a throughbore between the ends, and at least one valve for closing the throughbore; a cementing unit for providing pressurized fluid; and piping for connecting the output of the cementing unit to the BOP and into the throughbore of the BOP, a method comprising the steps of: a) using a pipe to install in the throughbore a test plug adjacent to the wellhead end of the BOP and in fluid communication with the interior of said pipe and the wellhead side of the valve; b) shutting the valve in the BOP against the exterior of said pipe; c) using the cementing unit and the piping to increase the pressure in the throughbore to a predetermined level; d) displaying the pressure in the piping as a function of time; and e) displaying the pressure in the piping as a function of time for the same blowout preventer system at an earlier time for which leakage was deemed to be within predetermined acceptable limits, wherein the time over which pressure is displayed in step (d) is less than the time over which pressure is displayed in step (e).