Patent attributes
A lead impression system having a downhole tool and a lead impression assembly assembled radially around the downhole tool is landed on a previously installed host casing hanger or a casing hanger being installed in the current/same trip to obtain a lead impression from the bore of the wellhead housing and indicate where the host casing hanger is located axially within the wellhead housing with respect to a feature on the bore of the wellhead housing from which the lead impression is obtained. Lead impression modules in the assembly have a lead pad that protrudes radially outward through a window on an outer sleeve according to a pressure differential between an internal and an external pressure of the lead impression assembly. The lead pad retracts to its pre-set position when the pressure differential exceeds a preset burst pressure.
