Abstract: 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.

Abstract: 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.

Abstract: 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 said wellbore; means for detecting said down hole conditions; and logic means for controlling said unit, said 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 correction 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.

Abstract: A downhole tool and apparatus is described for logging and/or remedial operations in a wellbore in a hydrocarbon reservoir. The tool comprises an autonomous unit (1) for measuring downhole conditions, preferably flow conditions. The autonomous unit comprises locomotion means (12) for providing a motion along said wellbore; means (14) for detecting said downhole conditions; and logic means (113) for controlling said unit, said logic means being capable of making decisions based on at least two input parameters. It can be separately attached to a wireline unit (22) connected to the surface or launched from the surface. The connection system (31, 32) between both units can be repeatedly operated under down hole conditions and preferably includes an active component for closing and/or breaking the connection.

Abstract: Drilling conditions are analyzed by, for example, measuring the torque applied at the surface to the drill string and the effective torque acting on the drill bit. The applied torque and effective torque are compared to determine torque loss. Likewise, applied weight on the drill string and effective weight acting on the drill bit may be measured and compared to determine drag losses. These measurements and comparisons may be done in real-time to diagnose unfavorable drilling conditions. The torque or weight measurements may be used to calculate a variable coefficient of friction acting on the drilling string. Trends in the torque or weight losses, or in the value of the coefficient of friction, may be observed on a plot of these quantities as a function of depth.