Abstract: An apparatus for detecting a connection between adjacent vertical panels having a first contact element positioned adjacent a bottom of one of the panels, a second contact element positioned adjacent a bottom of an adjacent panel, a first conductive line extending from the first contact element, a second conductive line extending from the second contact element, an electrical source for passing a current to at least one of the first and second conductive lines, and a detector connected to one of the first and second conductive lines for ascertaining the existence of a connection between the first contact element and the second contact element. The second contact element is positioned in proximity to the first contact element when the panels are connected together. The first contact element is affixed to a connector member of the panel. The second contact element is affixed in a channel of an adjacent panel. The connector member is a T-shaped member.

Abstract: This invention relates to a method of cementing a cylinder in a bore, such as a casing in a wellbore, which method involves the use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement which is utilized in a water slurry, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.