Coding system for use in a wellbore

摘要

A coding system for use in a wellbore formed in an earth formation is provided. The system comprises a tubular conduit (3) extending in the wellbore and being provided with at least one transmitter array, each transmitter array being arranged at a selected wellbore location and including at least one transmitter arranged in a selected pattern representative for said location. Each transmitter induces a field selected from a magnetic field and an electromagnetic field into the interior of the conduit. Further is provided a sensor (30) suitable to be lowered through the conduit and to interact with each field, and means for generating a signal representative of the interaction of the sensor with each field. <IMAGE>