Abstract: A pressure pulse generator for a downhole drilling tool is provided. The pressure pulse generator includes a stator with an orifice through which a stream of fluid passes, and a rotor intended to rotate opposite the stator to allow the flow of more or less liquid exiting the orifice of the stator. The rotor is equipped with an orifice, and the two orifices present a communicating area for the passage of the stream of fluid. The rotor is capable of passing fluid therethrough. A turbine with blades rotatable in response to fluid flow through the rotor may also be provided. The turbine is operatively connected to the rotor via a drive shaft. The fluid flow through the rotor may be used to rotate the turbine and provide power usable in the downhole tool.

Abstract: A pressure pulse generator for a downhole drilling tool is provided. The pressure pulse generator includes a stator with an orifice through which a stream of fluid passes, and a rotor intended to rotate opposite the stator to allow the flow of more or less liquid exiting the orifice of the stator. The rotor is equipped with an orifice, and the two orifices present a communicating area for the passage of the stream of fluid. The rotor is capable of passing fluid therethrough. A turbine with blades rotatable in response to fluid flow through the rotor may also be provided. The turbine is operatively connected to the rotor via a drive shaft. The fluid flow through the rotor may be used to rotate the turbine and provide power usable in the downhole tool.

Abstract: An apparatus for measuring the resistivity of earth formations penetrated by a wellbore having a conductive conduit. The apparatus includes an elongated sonde mandrel, a plurality of electrodes positioned at axially spaced apart locations along the mandrel, the electrodes being electrically insulated from the mandrel and from each other, the electrodes adapted to electrically contact the conduit and positioned collinearly so that the electrodes contact the conduit when the mandrel is radially displaced towards the wall of the conduit. Some electrodes are for injecting electrical current into the conduit, other electrodes are for measuring voltage drop along the conduit at axially spaced apart locations. The mandrel includes selectively extensible locking arms for urging the mandrel into contact with the conduit. The arms are radially positioned opposite to the electrodes.