Patent ID: 7222681
Filing Date: 2007-05-29
Classification: E21B

Abstract:
1. A method for communicating with a downhole tool deployed in a subterranean borehole, the method comprising: (a) deploying a drill string in a subterranean borehole, the drill string including a downhole tool connected thereto, the drill string being rotatable about a longitudinal axis, the drill string including a rotation measurement device operative to measure rotation rates of the drill string about the longitudinal axis, the drill string further including a flow measurement device operative to measure flow rates of drilling fluid in the drill string; (b) predefining an encoding language comprising codes understandable to the downhole tool, the codes represented in said language as predefined value combinations of drill string rotation variables and drilling fluid flow variables, the drill string rotation variables including rotation rate, the drilling fluid flow variables including flow rate; (c) causing the drill string to rotate at a preselected rotation rate; (d) causing the drilling fluid to flow in the drill string at a preselected flow rate; (e) causing the rotation measurement device to measure the rotation rate and the flow measurement device to measure the flow rate; and (f) processing downhole the rotation rate and the flow rate measured in (e) to acquire at least one code in said language at the downhole tool.