Cable used for geophysical measurement in oil and gas exploration, has interlocking Z-wire reinforcement forming smooth outer surface resisting ingress

摘要

Z-wire reinforcement (2.1) forms a smooth outer surface (2.2) resisting the ingress of media. The wires are wound around a core (3) in spiral formation, interlocking their shapes together with a frictional grip. The cable includes insulated conductors (4, 5) for current supply, and separately-insulated measurement and control lines (6-8). These connect to the remote measurement head at the far end of the cable, and where appropriate, to a mobile extraction unit. The conductors (4-8) are combined into a bundle. - To raise the torsional stiffness of the cable (1), the bundle is encased in plastic-impregnated glass fibers. Cable axial stiffness measured by the flexure length, is a function of mechanical properties of the Z-wires, including their ultimate tensile strength, impact length and cross-sectional geometry. A measurement fiber optic (8) cable is included. The Z-wires are so formed and distributed, that they enclose the core mechanically and media-tight, as well as forming a closed running surface (2.2). They are plated, e.g. galvanized, to prevent corrosion and leakage. There are 16 Z-wires with a Z-limb measurement of 4.5 mm. The core enclosed is 9 mm in diameter. The base of each Z wire is specially profiled to match the core casing (3.1) profile.