| 摘要 |
<p>A description of a cable for connection to sensors permanently downhole is provided, the cable comprising a plurality of elongate conductors capable of operative connection to sensors, a sheath surrounding the elongate conductors and holding the conductors so as to extend substantially parallel to an elongate axis, wherein the sheath has a cross-section, perpendicular to the direction of the elongate axis, which has a major dimension and a minor dimension. The cross-section of the cable is thus flattened and can be in the shape of an ellipse, a crescent or comprise a circle with wing-like portions attached on opposite sides of the circle. The sheath is made from a resilient material, so as to provide a robust outer surface of the cable which ensures the cable can be placed downhole without breaking. A number of the elongate conductors are grouped together and interweaved in a helical arrangement, so as to reduce electrical cross-talk between the conductors. Strengthening cords are included in the sheath which can be hollow to allow passage of fibre optic cables within the wire cords. A method of cementing a well is also provided, comprising forming a borehole, placing elongate tubing within the borehole to form an annulus in the borehole, and placing within the annulus a cable with a cross-section which has a major and a minor dimension, such that the minor dimension extends along a radius of the borehole, and passing cement, or thixotropic fluid, downhole to secure the cable in the annulus.</p> |
