| 主权项 |
1. A downhole isolation tool for use in providing a sealing barrier extending transversely across the bore of a pipe for isolating an upper section of the bore from fluid originating from a connected lower section of the bore, said pipe having a bore inlet at ground surface, said tool, when used in the pipe, comprising, in combination:
support means, connectable with the pipe at the bore inlet, for supporting and anchoring a plurality of downwardly extending segments of the tool; an isolation assembly for positioning lengthwise in the pipe bore at depth, said assembly comprising a linear assemblage of components including a front plate, a front seal element, a central body, a back seal element and a back plate, said seal elements being axially spaced apart, resilient, deformable and annular, each said seal element being positioned between one end of the body and a plate, whereby, when the plates and body are compressed together, the seal elements may be squeezed and deformed outwardly into sealing engagement with the pipe and may thereby combine with the outer surface of the body and the inner surface of the pipe to form a sealed annular space; a housing assembly for lowering the isolation assembly into the pipe bore and positioning it at the desired operational depth, said housing assembly being operative to be anchored at its upper end to the support means and connected at its lower end with the front plate, whereby the front plate may be held stationary and fixed in place by said housing assembly; a tubular vent rod means for connection with the back plate and extension through the isolation assembly and upper section of the pipe bore to ground surface; means, supportable by the support means, for tensioning the rod means to compress the plates and body together and deform the seal elements so that they sealably engage the pipe; monitoring means, extendable down through the upper pipe section bore and connectable with the isolation assembly, for circulating pressurized fluid from ground surface through the sealed space and back to ground surface, for providing an indication of seal leakage; whereby the isolation assembly may provide a sealing barrier having a pair of annular seal elements sealing against the pipe's inner surface at axially spaced apart intervals, the rod means may simultaneously provide a passageway for segregated venting of pipebore fluid from the pipe's lower section through the barrier to ground surface, the housing assembly may provide a means for lowering, holding and recovering the isolation assembly and the monitoring means may function to provide an indication as to whether a seal element is leaking. |
