| 摘要 |
A method of actuating a well tool includes the steps of: increasing pressure in a fluid line of a fluid metering device; closing a pilot-operated valve in response to the pressure increasing step; and discharging a predetermined volume of fluid from the metering device in response to the pressure increasing and valve closing steps. A fluid metering device for a well tool includes a piston separating chambers; and a pilot-operated valve which selectively prevents fluid communication between the chambers in response to at least a predetermined pressure being applied to a fluid line of the metering device, and which permits fluid communication through the valve between the chambers in response to pressure in the fluid line being less than the predetermined pressure. A greater pressure may be applied to the fluid line to thereby bypass the metering device and allow fluid to discharge from the line.
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