| 摘要 |
A dual acting hydraulic jarring tool which includes dual acting metering devices and is particularly well suited for coiled tubing application. A common annular chamber is formed between reciprocating cylindrical assemblies and dual engaging and metering devices are used to engage and meter hydraulic fluid at a predetermined rate flowing from one chamber to another chamber defined within the annular space. An improved retarding and metering mechanism is also disclosed which serves to retard relative telescoping movement of one cylindrical assembly relative to the other cylindrical assembly and meter the hydraulic fluid at the predetermined rate. The present invention is particularly well suited for coiled tubing application due to its low load requirements, minimal overall length and enlarged interior bore for the passage of downhole tools; however, the present invention is well suited for use with conventional drilling strings as well.
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