| 摘要 |
<p>The present invention provides a downhole cementing apparatus (100) run into a borehole on a tubular. The apparatus is constructed on the pipe (110) in such a way that pressure surge during run-in is reduced by allowing fluid to enter the pipe and utilise the fluid pathway of the cement. In one aspect of the invention, an inner member (135) is provided that filters fluid as it enters the fluid pathway. In another aspect of the invention, various methods are provided within the cementing apparatus to loosen and displace sediment in the borehole prior to cementing, and to cause a separation of materials in the borehole by running in a tubular string. <IMAGE> <IMAGE></p> |
