Abstract: Apparatus and method for noninvasive surface or remote monitoring of activity downhole in a cased bore hole wherein vibrations transmitted through the casing are detected by a vibration transducer coupled to the casing to obtain information about the activity occurring downhole in the cased bore hole. In one embodiment, an acoustic wave or vibration detector is coupled to the wellhead of an existing well or wells. The detector detects the acoustic waves or vibrations transmitted through the existing well that are caused by the drilling of the new well in close proximity to the existing well casing. When the monitored vibrations meet a predeterminedd criteria indicating a closely approaching drill bit or the drill bit striking the casing of an existing well, an alarm signal is produced to warn of the close approach or impact so that appropriate responsive action may be taken.

Abstract: In a safety system for controlling the closing of a primary valve in response to an indication of an undesirable condition from a monitoring device, the system including a valve arrangement which supplies operating fluid to the primary valve and an operator connected between the monitoring device and the valve arrangement for controlling the operation of the latter in response to the indication produced by the monitoring device, the speed and reliability of the system is improved by providing a direct fluid connection between the output of the monitoring device and the operator, whereby the system is directly controlled by the fluid pressure variations at the output of the monitoring device. Preferably, the system includes an hydraulic subsystem and a pneumatic subsystem.

Abstract: In a safety system for controlling the closing of a primary valve in response to an indication of an undesirable condition from a monitoring device, the system including a valve arrangement which supplies operating fluid to the primary valve and an operator connected between the monitoring device and the valve arrangement for controlling the operation of the latter in response to the indication produced by the monitoring device, the speed and reliability of the system is improved by providing a direct fluid connection between the output of the monitoring device and the operator, whereby the system is directly controlled by the fluid pressure variations at the output of the monitoring device. Preferably, the system includes an hydraulic subsystem and a pneumatic subsystem.