DRILL STRING ROTATION ENCODING

摘要

A method for communicating with a downhole device is provided. The meth od includes predefining an encoding language including codes understandable to the device, the codes represented in the language as predefined value combinations of drill string rotation variables such as rotation rate or duration. The method further includes rotating a drill string at first and second rates and measuring the rotation rates downhole. The first measured rotation rate is processed downhole in combination with the second measured rotation rate to acquire a code in the language at the downhole device. Embodiments of the invention are useful, for example, for transmitting commands from the surface to a downhole device such as a directional drilling tool. Exemplary embodiments o f this invention advantageously provide for quick and accurate communication with a downhole device without substantially interrupting the drilling process.