Down hole tool and method

摘要

A down hole tool and apparatus is described for logging and/or remedial operations in a wellbore in a hydrocarbon reservoir. The tool comprises an autonomous unit for measuring down hole conditions, preferably flow conditions. The autonomous unit comprises locomotion means for providing a motion along the wellbore; means for detecting the down hole conditions; and logic means for controlling the unit, the logic means being capable of making decisions based on at least two input parameters. It can be separably attached to a wireline unit connected to the surface or launched from the surface. The connection system between both units can be repeatedly operated under down hole conditions and preferably includes an active component for closing and/or breaking the connection.