Patent ID: 7451819

Claim:
An apparatus for use in an openhole well extending from a well surface, comprising: a closure member adapted to be positioned in the openhole well, the closure member defining a chamber therein, the chamber having a pressure lower than pressure in the wellbore at a selected wellbore interval; and at least one port selectively openable to establish communication between the chamber and the wellbore interval in the openhole well, wherein the at least one port when opened creating a fluid surge into the chamber to generate a transient underbalance pressure condition in the wellbore interval, the fluid surge to remove filtercake from the wellbore interval; wherein the closure member and at least one port are configured based on the transient underbalance pressure condition derived according to one of empirical data and modeling software for characteristics of an interval of the openhole well in which the transient underbalance pressure condition is to be created.