Gauge for remotely indicating the pressure of a subterranean formation

Abstract

An apparatus particularly adaptable for recording pressure of subterranean formations in a downhole pressure gauge by providing a variable capacitance in response to changes in ambient pressure. The apparatus comprising a closed tubular housing having a deformable conductive end with an interior and exterior surface, the deformable end forming a diaphragm subject to the pressure in which the housing is positioned, increased pressure deflecting the deformable end inwardly. The deformable end has an axial boss portion extending inwardly from the inner surface. A stator having a central hub is positioned within the housing, the hub having an opening therein which receives the boss portion. The stator has a planar portion positioned adjacent to and spaced from the interior surface of the housing deformable end, the portion of the planar surface of the stator adjacent the housing deformable and interior surface being of conductive material forming a capacitive relationship between the housing deformable end so that when the deformable end is concaved inwardly by increased ambient pressure of the fluid environment in which the apparatus is positioned, the capacitive relationship between the stator and the deformable end changes to provide an indication of the amount of ambient pressure applied to the exterior of the housing.