Abstract: A cable for recording conditions in a well bore, the cable including a tube having a generally smooth outer surface and an inner surface defining an elongated, uninterrupted opening extending throughout the length of the tube, at least one fiber optic, disposed within the opening of the tube, the fiber optic extending the length of the tube, an electrical conductor disposed within the opening of the tube, the electrical conductor extending the length of the tube, and insulating material disposed within the tube, the insulating material encapsulating the fiber optic and electrical conductor so as to form a core, wherein the core is of substantially smaller diameter than the opening to permit thermal expansion of the fiber optic, the conductor and the insulating material. The size of the tube and the core may be selected such that there is an annulus between the inside surface of the tube and the outside surface of the core, the annulus providing a flowpath extending the length of the tube.

Abstract: The present invention generally pertains to apparatus and a method for continuously injecting a tracer in a borehole to thereby enable continuously measuring the flow of effluents in the borehole, i.e. either in an injection well or production well, of an oil, gas or geothermal field. The apparatus and method comprises positioning capillary tubing within the borehole, the tubing having a flowpath extending continuously from the surface to a desired depth, the capillary tubing having at least one sensor suspended in the borehole at the desired depth, injecting a tracer element into the tube from a pressurized source at the surface, releasing the tracer element at the desired depth and detecting the presence of the tracer.