Abstract: A wireline logging assembly includes a cable having primary conductors, secondary conductors, and a central conductor. A first power source excites the primary conductors using a first propagation mode. A first telemetry transceiver excites the primary conductors using a second propagation mode orthogonal to the first mode. A second power source excites the secondary conductors and a second telemetry transceiver excites the central conductor. In one embodiment, the diameter of the primary conductors is greater than a diameter of the secondary conductors. The primary conductor includes four primary conductors symmetrically positioned around the center conductor and the secondary conductors include a secondary conductor positioned in the interstice between each pair of adjacent primary conductors.

Abstract: A downhole tractor is provided that may be used in open or cased wells, and is also designed for use in open holes having a variety of soil/formation consistencies (e.g., soft, firm, rigid, etc.), varying diameters and non-uniform and irregular bore profiles. The tractor may include a track assembly including a plurality of idler wheels and a continuous track rotatably disposed around the idler wheels. A motor may be adapted to rotate the track around the idler wheels. Upper and lower arms may be pivotally connected to opposite ends of the track assembly and pivotally connected to a tractor housing. An actuator arm or link assembly may be provided to impart an outward force to the track assembly to move the track assembly outwardly into an open position and a retracting force to retract the track assembly into a closed position. A rotatable screw may be connected to a second motor, or a rod may be connected to a hydraulic system, to actuate the actuator arm or link assembly.