Abstract: Embodiments of a method for detecting well integrity failure are disclosed herein. In general, embodiments of the method utilize seismic signals for detection. In particular, embodiments of the method may use recording of passive or active seismic signals. Further details and advantages of various embodiments of the method are described in more detail in the application.

Abstract: Embodiments of a method for detecting well integrity failure are disclosed herein. In general, embodiments of the method utilize seismic signals for detection. In particular, embodiments of the method may use recording of passive or active seismic signals. Further details and advantages of various embodiments of the method are described in more detail in the application.

Abstract: An image intensifier includes a photocathode (11) with a face plate (22). A conductive layer (24) is disposed outwardly from the face plate (22). A grounded conductor (16) is electrically coupled to the conductive layer (24) and grounds the conductive layer (24).

Abstract: An image intensifier includes a photocathode (11) with a face plate (22). A conductive layer (24) is disposed outwardly from the face plate (22). A grounded conductor (16) is electrically coupled to the conductive layer (24) and grounds the conductive layer (24).

Abstract: A mechanism for locking and unlocking a reciprocating shaft includes a plate fixed to the shaft having an inclined surface. A housing surrounds the shaft and plate having a wall surrounding the inclined surface. A set of balls is located between the inclined surface and the housing wall. An assembly is translatable relative to the shaft and is biased by a spring to jam the balls between the inclined surface and the housing wall to lock the shaft against reciprocation. The assembly is movable against the force of the spring by a fluid pressure actuated cylinder to move the balls away from the inclined surface to unlock the shaft.

Abstract: An isolation valve includes a housing having a port and a seal plate for sealing the port. The seal plate is linked to a shaft which carries a guide frame. To close the port, a drive mechanism drives the shaft linearly in one direction. The seal plate first moves linearly with the shaft until the guide frame stops against the housing. The seal plate then moves linearly in a direction perpendicular to a surface of the housing containing the port until it seals the port. Motion of the drive shaft in the opposite direction causes the seal plate to retrace its path. In one embodiment, the valve includes a second seal plate for sealing a second port. A spring between the guide means and the shaft provides pre-load which maintains the seal plates in a retracted position until the frame stops against the housing. An extension spring between the first and second seal plates eliminates play in the link mechanism and extends valve life.