| 摘要 |
A tracer-liner portion comprises an inner tube and an outer tube, each comprising at least one wall having an internal surface and an external surface,the walls of the inner tube and the outer tube being impermeable to fluid flow, said outer tube having an internal diameter which is larger than the outer diameter of said inner tube, said inner tube being arranged coaxially within said outer tube such that at least a portion of the external surface of said inner tube is covered by said outer tube; the internal diameter of the outer tube exceeds the outer diameter of the inner tube by an amount sufficient to form a space between the external surface of the inner tube and the internal surface of the outer tube, and a tracer material containing a tracer compound is present in said space. |
