Patent ID: 8939204
Filing Date: 2015-01-27
Classification: E21B

Abstract:
1. A method of communication between a device located in a borehole and a remote sensor, comprising the steps of: providing a string of a plurality of connected components, one or more vessels running along the string to form a continuous, substantially enclosed fluid path; incorporating a device into the string so that the device is in communication with the fluid path; inserting the string into a borehole so that the device is located below a surface into which the borehole is formed and the fluid path extends from the surface to the device; providing a pressure sensor at or near the surface, the pressure sensor being adapted to sense the pressure of the fluid in the fluid path; substantially filling the fluid path with a pressurised fluid; over a communication period, venting fluid, under the control of the device, from the fluid path to an exterior of the string at or near the device on one or more occasions, so that the resulting decrease in pressure in the fluid in the fluid path can be detected by the pressure sensor; and during the communication period introducing fluid into the fluid path at a rate below 30 gallons/minute [0.113 m