Abstract: One or more pup joints are provided in a tubular string at one or more predetermined locations. The seal bores are recessed to protect them from passing tool until needed as a sealing location for a packer or bridge plug having a metal-to-metal seal that is radially extended into sealing contact with the seal bore surface. The seal surface can be recessed to protect it from passing tools. A coating or sleeve can be fit to the sealing surface that is penetrated by the sealing element of the packer or bridge plug for the metal to metal seal. The presence of the protective sleeve can also enhance the metal to metal seal by abutting the sealing element on opposed sides after the sealing element penetrates through the sleeve.

Abstract: A communication system is disclosed enabling communication from a surface location to a downhole location where instructions communicated are executed. The system employs accelerometers to sense vibrations traveling within the annulus fluid or the tubing string. The accelerators provide signals representative of the vibration generated at the surface of the well to a microcontroller. The microcontroller is programmed to energize a nichrome element to actuate the downhole tool in response to a user-defined vibration sequence. The vibration sequence includes a defined number of vibration cycles. Each cycle includes alternating periods of vibration and no vibrations with each period lasting for a defined length of time. The user may program the parameters of the sequence and arm the vibration receiving unit on site through a handheld terminal that interfaces with the microcontroller.

Abstract: A communication system is disclosed enabling communication from a surface location to a downhole location where instructions communicated are executed. The system employs accelerometers to sense vibrations traveling within the annulus fluid or the tubing string. The accelerators provide signals representative of the vibration generated at the surface of the well to a microcontroller. The microcontroller is programmed to energize a nichrome element to actuate the downhole tool in response to a user-defined vibration sequence. The vibration sequence includes a defined number of vibration cycles. Each cycle includes alternating periods of vibration and no vibrations with each period lasting for a defined length of time. The user may program the parameters of the sequence and arm the vibration receiving unit on site through a handheld terminal that interfaces with the microcontroller.