Abstract: An electro-mechanical indicator system for signaling when a droppable object (such as, for example, a dart, plug or ball) is released during well cementing operations. A body section has first and second chambers divided by a fluid and pressure sealing barrier. A mechanical trigger mechanism is situated in the first chamber, which is exposed to elevated pressures and harsh wellbore fluids. Less robust components, such as sensor(s), power source(s), and signal device(s) located in the second chamber, remain isolated from the wellbore environment and elevated pressures.

Abstract: A remotely operated lifting top drive cement head is provided having a high tensile strength, as well as the ability to swivel or rotate about a central vertical axis. The cement head permits selective launching of darts, setting plugs, balls or other objects which can be held in place within the cement head without being damaged or washed away by slurry flow, but which can be beneficially launched into said slurry flow at desired point(s) during the cementing process. The internal components of the cement head can be easily accessed using interrupted thread connections that can be quickly and easy connected and disconnected in the field without requiring specialized equipment. The cement head can be rigged up and remotely operated without requiring the lifting of personnel off the rig floor to actuate the tool or observe tool status.