| 摘要 |
<p>Wireline operation depth control in cased wells (12) can be substantially improved by attaching a combined magnetic and radioactive marker (15) to the casing (12) in the vicinity of the zone of interest. A cased hole log is then performed, such as a perforation depth control (PDC) log, using both a casing collar locator (32) and a gamma ray sensor (34). The marker (15) produces distinctive spikes (56 and 61) on the logs (51 and 41) from both sensors (32 and 34). The casing collar log (51) is tied in to the gamma ray log (41) simply by aligning these distinctive spikes (56 and 61) on both logs. This helps to ensure that subsequent cased hole wireline operations, such as perforating, that rely solely on a collar locator (22) for depth control are performed at the correct depth.</p> |
