| 摘要 |
<p>A remote cement plug launching system for use in cementing wells, comprises two or more cementing plugs (56, 58) and a dart (34) for each to seat in and occlude the respective plug, passage of a dart through one plug (56) to reach a lower plug (58) being assisted by providing guide tube means (300) extending from an upper plug to the dart seat (250) of a lower plug. The invention also includes a plug per se having dependent therefrom the guide tube means. </p> |
