Devices and methods to reduce the effects of the annulus of a downhole tool

A method for reducing the effects of the annulus of a downhole tool comprises placing the downhole tool in a borehole, wherein the downhole tool comprises at least a movable section positioned between a source energy and a receiver on the downhole tool; and activating the at least one movable section to reduce a thickness of at least one of a layer of sludge, a sludge deposit, or both, between the downhole tool and a borehole wall. A downhole tool comprises a power source and a receiver placed on the downhole tool; at least a movable section provided between the power source and the receiver; and an activation mechanism for reducing a thickness of at least one of a layer of sludge, a sludge deposit, or both, between the downhole tool and a wall of a survey.