Abstract: A downhole tool for use in a cased or lined well bore (40), the tool including a barrier (36) arranged on an outer surface of the tool. The barrier may be of a resilient material so that it can be deformed on actuation to control the passage of fluid between the tool and the casing or liner. Fluid flow is thus selectively diverted through flow paths (22) in the tool. Embodiments are described for actuating the barrier by hydraulic means and for filtering the fluid within the flow paths.

Abstract: A control sub for use with a hydraulically operated downhole tool. In an embodiment, the sub comprises an outer sleeve connected to a work string and an inner sleeve slidably engaged to the outer sleeve by matching hex profiles, connected to the downhole tool. Radial ports in the outer sleeve provide selective circulation of fluid from the tool and by closing these ports with the sleeve fluid pressure in to the downhole tool can be controlled. Closure is effected by setting down weight on the sub against the tool. An indexing mechanism is also described to keep the tool in a configuration, which maintains pressure on the tool. The sub is suitable for use with an expander tool.

Abstract: A downhole tool for use in the removal of burrs or other unwanted material from an inner surface of a pipeline, well casing or other tubular. The tool has a plurality of milling elements, which may be biased against the surface or retracted from the surface to disengage the tool from the tubular. A drop ball mechanism with a fluid by-pass is described for disengaging the milling elements.

Abstract: A downhole tool (10) for selectively circulating fluid in a borehole is disclosed. The tool operates via the use of a combination of deformable drop balls (36) and smaller hard drop balls (40). In use a deformable drop ball (36) moves a sleeve (20) exposing a radial port (30,32) to provide fluid circulation radially from the tool. The smaller drop ball (40) can then obstruct the radial port (32,30) and by the increased pressure the deformable drop ball (36) is extruded through the tool. The resulting pressure differential as the drop ball (36) moves causes the sleeve (20) to rise, releasing the smaller drop (40) ball and closing the radial port (32,30). The process can be repeated to selectively circulate fluid through the tool.