| 摘要 |
An annulus pressure responsive tool of the type which contains lateral circulation ports and a ball valve, each operable between open and closed positions to configure the tool into different modes of operation. These modes include a well test position in which the ball valve is open and the circulation ports are closed, a blank position in which the ball valve and circulation ports are both closed, and a circulating position in which the ball valve is closed and the circulating ports are open. Through manipulation of annulus pressure, the tool mode can be changed during the annulus pressure release to move out of the well test position and into the blank and circulating positions. An operating mandrel assembly is described which is slidably disposed within the exterior housing of the tool and whose movement dictates the positions of both the circulation ports and the ball valve. The operating mandrel is moveable by means of an annulus pressure conducting channel which is capable of receiving, storing and releasing annulus pressure increases. A ratchet assembly associates the operating mandrel assembly and housing and functions as an overrideable position controller to dictate response of the operating mandrel assembly to annulus pressure changes. The ratchet assembly contains a pair of ratchet balls which travel in ratchet slots on a ratchet slot sleeve. The ratchet slots feature a well test travel path within which the ratchet balls are maintained during normal operation of the tool in its well test position. The ratchet balls may be redirected into a secondary ratchet path and moved to ratchet ball positions which permit the operating mandrel assembly to be moved to positions corresponding to blank and circulating modes for the tool. A fluid metering assembly is featured which includes a flow path towards the fluid spring during annulus pressurization permits relatively unrestricted fluid flow. A flow path is provided away from the fluid spring during a release of annulus pressure provides metered flow to provide an operator sufficient time to generate an annulus pressure increase to move the ratchet balls out of the well test travel path and into the secondary path. A hydraulic bypass assembly selectively reduces the time required for portions of the metered transmission of stored fluid pressure away from the fluid spring. It includes a bypass mandrel and fluid communication bypass grooves which increase the flow of fluid during portions of the pressure release.
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