Patent attributes
A wiper plug that includes an elongated body member having a forward end, a rearward end, and an open central bore; spaced radially outwardly projecting wiping flanges made of flexible material and configured to extend beyond the inner diameter of the pipe to be cleaned but that deform to apply contact wiping pressure to the inner diameter of the pipe as the wiper plug travels through the pipe; and shearing elements that extend from the rearward end of the elongated body member by a distance that is greater than the inner diameter of the pipe to be cleaned. The shearing elements hold the wiper plug in position in between two connected pipe sections while the open central bore allows cement to flow therethrough. Also, a carrier pipe for the wiper plug and method of use thereof for cleaning cement from the wellbore annulus of long casing strings.
