| 摘要 |
<p>An apparatus and method for circulating fluid in a borehole is described. The apparatus comprises a tubular assembly (1; 40; 60) which has an axial through passage (21, 18; 47; 19) between a fluid inlet (21) and first fluid outlet (19). The fluid inlet (21) and the first fluid outlet (19) are connected (13, 20) in a work string which is supported from the surface above the borehole. There is a second outlet (16; 42, 48) which extends generally tansversely of the assembly (1; 40; 60). An obturating member (9) is moveable between a first position in which the second fluid outlet (16; 42, 48) is closed an a second position which permits fluid flow through the second outlet (16; 42, 48). An engagement mechanism (12, 6, 7; 68, 69) is moveable between an engaged configuration in which the obturating member (9) is maintained in one of the first and second positions, and a disengaged configuration in which the obturating member (9) is in the other of the first and second positions. The tubular assembly (1; 40; 60) is coupled to a shoulder which is engageable with the formation in the borehole to engage or disengage the engagement mechanism (12, 6, 7; 68, 69). Setting down weight on the work string may cause a formation of the borehole to exert a force on the shoulder which may result in the second outlet (16; 42, 48) being opened.</p> |
