| 摘要 |
PCT No. PCT/NO94/00216 Sec. 371 Date Aug. 9, 1995 Sec. 102(e) Date Aug. 9, 1995 PCT Filed Dec. 30, 1994 PCT Pub. No. WO95/18288 PCT Pub. Date Jul. 6, 1995A downhole tool for pressure testing of oil and gas wells comprises a generally tubular main tool (1), which is provided with an internal passage (2) and is arranged for attachment at the lower end of a drill pipe string. The main tool (1) is on its outside provided with an inflatable packing element (10), which may be supplied with and relieved of inflating medium via an annular slide valve (5) arranged inside the main tool (1). The slide valve has two active positions, one on each side of a closing initial position, and the slide valve is brought to the active positions by an auxiliary tool (18) which may be run into the passage (2) of the main tool and attached releasably in the slide valve (5). By pressure on the upper side of the auxiliary tool (18), the slide valve may be moved to one of its active positions against the action of a valve spring (6), and by traction in a cable attached to the auxiliary tool (18) the slide valve (5) may be moved to its other position against the action of the same valve spring (6). Upon completed pressure testing and relieving of the packing element (10), the auxiliary tool (18) may be freed from the slide valve (5) by varying the traction in the cable in order to release and free a locking mechanism (36-39) in the auxiliary tool (18), whereupon the latter may be pulled up to the surface.
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