Patent attributes
A downhole tool (10) for use in isolating a formation in a well bore from fluid pressure introduced from the surface. Mounted in a work string, the tool provides an axial throughbore (18) and radial outlets (40, 42) above and below a permanent sealing element (26), such as a diverter cup. Valve members (44, 50) which may be nested sleeves located within the axial bore are manipulated by activation through the work string, to move sequentially such that (a) a first circulation path is created around the seal, via the radial outlets and independent of the axial throughbore; (b) the axial throughbore is obstructed and a second circulation path is estate fished between the axial throughbore and the upper radial outlet; and (c) flow is re-established through the axial bore while maintaining the second flow path.
