| 摘要 |
A debris screen, sealingly and releasably latched to the top of a polished bore of a downhole tool for preventing the ingress of debris into the polished bore. Typically the debris screen is connected to a tieback receptacle of a liner hanger assembly. The debris screen is connected to a setting tool and is axially moveable on the setting tool permitting the setting tool to be stroked inside the liner hanger assembly during normal operations, such as cementing while retaining the debris screen at the top of the tieback receptacle at all times except during the final stages of retrieval. The debris screen has a tubular sleeve having a plurality of ports, covered by a wedge wire screen through which fluids can flow. Further, the latching mechanism has a plurality of ports to permit the flow of debris-free fluids from the wellbore into the annulus between the setting tool and the downhole tool.
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