Abstract: In one aspect, an apparatus for turning a corner, the apparatus being disposed adjacent to a grounded surface and comprising: a turntable platter, rotatably coupled to the grounded surface, for orienting a line-drawn trolley; a locking mechanism, disposed on the turntable platter, for preventing rotation of the turntable platter with respect to the grounded surface; a first turntable guide, removably coupled to the turntable platter, for guiding a draw line through the line-drawn trolley; a second turntable guide, removably coupled to the turntable platter, for guiding the draw line through the line-drawn trolley; a first stationary diverter, removably coupled to the grounded surface, for diverting the draw line around the line-drawn trolley; and a second stationary diverter, removably coupled to the grounded surface, for diverting the draw line around the line-drawn trolley.

Abstract: A siphon is disclosed for siphoning liquid between locations. The siphon comprises a flow duct for a liquid and a plug which is arranged to move in sealing contact within the flow duct. The siphon further comprises means for causing the plug to move along the flow duct to draw liquid along the flow duct and thus transfer liquid from the one location to another.

Abstract: An apparatus and method for minimizing the effects of a common mode voltage signal in downhole logging tools utilized to determine the resistivity of an adjacent portion of a borehole wall. Two current electrodes are energized by an excitation source to create an oscillatory electric field in a borehole wall. A voltage drop across a segment of the borehole wall is measured by two voltage electrodes, and the differential voltage is used in combination with a measured current flow to determine a resistivity value for the borehole wall. A common mode voltage in front of the two voltage electrodes is measured and minimized by controlling the excitation source, thereby reducing the resistivity measurement error.

Abstract: A power delivery system for a wireline tool includes two independent power transmission loops operating on a standard six-conductor cable. The two loops each connect directly to a respective terminals of a DC auxiliary power supply. Each loop also couples through a transformer to an AC instrument power supply. Another transformer for telemetry signals facilitates bidirectional communication between the downhole tool and an uphole computer.

Abstract: An NMR logging tool for conducting NMR measurements in a plurality of sensitive volumes ranging up to a meter from the tool. The tool comprises a magnetic assembly using one or more permanent magnets and at least one pole piece for extending a magnet pole and shaping the magnetic field to simulate a magnetic monopole in a sensitive volume within the formation. Different embodiments of a segmented antenna enable directional NMR logging. The tool embodiments and methods of their use are suitable for wireline or LWD logging, and can be used for directional drilling.

Abstract: A power delivery system for a wireline tool includes two independent power transmission loops operating on a standard six-conductor cable. The two loops each connect directly to a respective terminals of a DC auxiliary power supply. Each loop also couples through a transformer to an AC instrument power supply. Another transformer for telemetry signals facilitates bidirectional communication between the downhole tool and an uphole computer.

Abstract: A semi-conductor assembly includes a conductive stud and a semi-conductor device mounted on the stud so that a first contact area of the device is thermally and electrically connected thereto. Thermally and electrically connected to a second contact area of the device is an expanded head portion of an electrical lead. A body is shaped to define a recess in which the stud is engaged so that the device is accommodated in the space defined between the stud and the walls of the recess, the electrical lead extending through an aperture in one of said walls. Sealing means prevents ingress of foreign material through the aperture into said space, and a resilient member is trapped and deformed between the head portion of the lead and the body so that the head portion of the lead is urged into pressure contact with the device.