Patent ID: 7256706

Claim:
A downhole communication system for transmitting signals in a hydrocarbon fluid product well, the system comprising: a control unit at or near the earth surface; a downhole signal converter a signal transmission conduit for transmitting signals between said control unit and said downhole signal converter; a downhole measuring and control assembly, which is equipped with a wireless signal transducer, and wherein; said signal converter and said signal transducer are located at different depths in the well and form a wireless communication link there between; the well is a multilateral well comprising a main wellbore and one or more wellbranches; the signal transmission conduit extends from the wellhead into the main wellbore; at least one signal converter is located at or near a downhole branchpoint; and said downhole measuring and control assembly is located in at least one wellbranch away from the branchpoint; said signal transducer and said signal converter forming a wireless link along a substantial part of the length of said wellbranch.