Abstract: A surfactant composition is used to repel down-hole fluids such as crude oil and water to prevent their adherence to a down-hole instrument for an extended period of time. A down-hole fluid repelling surfactant, preferably in the form of a liquid solution, is applied to an exterior surface of the instrument, dried, and polished to prevent down-hole fluids from adhering to the surface. A preferred liquid surfactant solution contains as an active ingredient an amount of tricresyl phosphate effective to repel down-hole fluids such as oil and water.

Abstract: A downhole power supply system having a variable voltage surface power supply and a downhole shunt voltage regulator between which is disposed in series an energy transducing device. The shunt voltage regulator comprises a current control device which controls the amount of current shunted to the power return line between the series connected energy transducing device and the input to the voltage regulator to maintain a selected voltage at the voltage regulator. The shunt regulator senses the voltage on the power line, compares the sensed voltage to the selected voltage, and controls the shunt current control device to conduct more or less current in the event that the two voltages are not equal. As a result, changing the voltage at the remote power source will change the voltage across the transducing device and the amount of current conducted through it thus changing its output.

Abstract: The down-hole instrument cable includes a hermetically sealed optical fiber surrounded by a protective buffer layer and a protective gel within a protective tube. A layer of electrical conductors between an inner insulator and outer insulator layer surrounds the protective tube, and electrically conductive strength member strands surround the outer insulator layer. The cable includes an electrically conductive cable head body electrically connected to the strength member strands, and an electrically conductive contact subassembly, through which the optical fiber and electrical conductors extend. The contact subassembly provides a first electrical terminal for connection to the down-hole instrument, the layer of electrical conductors provides a second electrical terminal, and the optical fiber provides an optical signal pathway for the down-hole instrument.

Abstract: A surfactant composition is used to repel down-hole fluids such as crude oil and water to prevent remote viewing cameras from being obscured by such fluids, for extended periods of time. An effective amount of a down-hole fluid repelling surfactant, preferably in the form of a liquid solution, is applied to an exterior surface of an optical element of the viewing instrument, dried, and polished to prevent down-hole fluids from adhering to the surface of the optical element. A preferred liquid surfactant solution contains as an active ingredient an amount of tricresyl phosphate effective to repel down-hole fluids such as oil and water.

Abstract: A lighting system for a logging instrument probe for inspecting a passageway having different diameters. The lighting system has a light assembly of a plurality of light sources arranged in tandem. The light assembly is mounted under the sensor to selectively illuminate that part of the passageway lying within the sensor's field of view. Three extension legs are used to rigidly mount the light assembly forward of the sensor camera and at least one leg provides a conduit for the electrical wires used for powering the lights. The first light source is reverse facing. The length of the legs is selected to position a first light source at a particular distance away from the camera for inspection of the part of the passageway having the smaller size. A second light source is mounted in the light assembly and is forward facing. Connected between the first light source and the second light source is a spacer.

Abstract: An instrument probe contains a video camera and light source which is positioned in front of the camera for illuminating the passage being inspected, such as a bore or a casing. The power source for the instrument probe is located at the surface. A support cable contains an optical fiber for conducting camera signals to the surface and electrical conductors for conducting power from the surface to the instrument probe. The outer electrical conductor includes strands of copper alternating with and in electrical contact with strength member strands. The cable is enclosed in a stainless steel outer sheath. The support cable is coupled to the instrument probe by three fluid seals. The first seals the outer sheath in the probe. The second seals at the breakaway connection and the third seals at the probe bulkhead. The second and third seals include the use of adhesive caulking.

Abstract: A cable containing an optical fiber for conducting communication signals and electrical conductors for conducting power. The optical fiber is centrally located. An inner layer includes electrical conductors and an outer layer includes electrical conductors interspaced with strength members. The interspaced strength members are in electrical contact with the electrical conductors and lower the loop resistance so that a power source may be used at one end of the cable and the equipment to be powered at the other without requiring an excessively large voltage at the power source. In one embodiment, the strength members are formed of steel and are interspaced such that there is one strength member per two electrical conductors. The cable is enclosed in a smooth and continuous stainless steel outer sheath.

Abstract: An instrument probe contains a video camera and light source which is positioned in front of the camera for illuminating the passage being inspected, such as a bore or a casing. The power source for the instrument probe is located at the surface. A support cable contains an optical fiber for conducting camera signals to the surface and electrical conductors for conducting power from the surface to the instrument probe. The outer electrical conductor includes strands of copper alternating with and in electrical contact with strength member strands. The cable is enclosed in a stainless steel outer sheath. The support cable is coupled to the instrument probe by three fluid seals. The first seals the outer sheath in the probe. The second seals at the breakaway connection and the third seals at the probe bulkhead. The second and third seals include the use of adhesive caulking.