Abstract: A method and apparatus for transmitting information to the surface from down hole in a well in which a pulser is incorporated into the bottom hole assembly of a drill string that generates pressure pulses encoded to contain information concerning the drilling operation. The pressure pulses travel to the surface where they are decoded so as to decipher the information. The pulser includes a stator forming passages through which drilling fluid flows on its way to the drill bit. The rotor has blades that obstruct the flow of drilling fluid through the passages when the rotor is rotated into a first orientation and that relieve the obstruction when rotated into a second orientation, so that oscillation of the rotor generates the encoded pressure pulses. An electric motor, under the operation of a controller, drives a drive train that oscillates the rotor between the first and second orientations.

Abstract: A method of making a stator for a helicoidal pump/motor formed by a network of fibers encapsulated in an elastomer. The core is formed by laying up elastomeric preforms into helical grooves formed in a mandrel and wrapping an elastomeric sheet around helical projections formed in the mandrel. Successive strips of calendered rubber/wire cloth are then laid up into the grooves so as to fill the grooves, which are then wrapped in another layer of calendered rubber/wire cloth. The assembly is then filament wound with reinforcing cords and compression cured so as to bond the elastomeric components into a unitary element. The assembly is then placed in the stator housing and additional elastomer injected into the annular passage between the stator housing and the assembly. The completed assembly is then further cured so that the injected and previously cured elastomers bond to form a unitary structure having good strength and heat transfer capabilities.

Abstract: A system for cooling electronic components in the downhole assembly of a drill string through which a drilling fluid flows. The cooling system includes a thermoelectric cooler that conducts heat from the electronic component to a first heat transfer surface of a thermal conductor. The heat received by the first heat transfer surface is transferred within the thermal conductor to a second heat transfer surface that then transfers the heat to a housing. The housing transfers the heat to the drilling fluid flowing over the housing. To ensure good conductive heat transfer between the electronic component, the thermoelectric cooler, the thermal conductor and the housing, and to absorb shock, vibration and differential thermal expansion, these components are supported on a spring mechanism that generates a force that biases the electronic component against the thermoelectric cooler, the thermoelectric cooler against the thermal conductor and the thermal conductor against the housing.

Abstract: A system for cooling electronic components in the downhole assembly of a drill string through which a drilling fluid flows. The cooling system includes a thermoelectric cooler that conducts heat from the electronic component to a first heat transfer surface of a thermally conductive chassis. The heat received by the first heat transfer surface is transferred within the chassis to a second heat transfer surface that then transfers the heat to a housing. The housing transfers the heat to the drilling fluid flowing over the housing. To ensure good conductive heat transfer between the chassis and the housing, the chassis portions are urged outwardly toward the housing surface. A conformable thermal interface material preferably forms the chassis second heat transfer surface.