Abstract: A method of locating bore-lining tubing, such as a liner (120), in a drilled bore (106) comprises selecting a buoyant material, such as air (138), having a density lower than the density of an ambient fluid, such as well fluid (180, 182). The buoyant material (138) and an inner tubing (140) are located within the bore-lining tubing (120) with the inner tubing (140) extending from a distal end of the bore-lining tubing to a proximal end of the bore-lining tubing. The inner tubing (140) is sealed to the distal end of the bore-lining tubing (120) and to a portion of the bore-lining tubing (120) spaced from the distal end to define an inner annulus (152) between the inner tubing (140) and the bore-lining tubing (120). A volume of the buoyant material (138) is retained within the inner annulus (152). An assembly (168) comprising the inner tubing (140) and the bore-lining tubing (120) and containing the volume of buoyant material (138) is run into a drilled bore (106).

Abstract: A method of conditioning a well bore featuring an annulus (50) between a bore-lining tubing (20) and a surrounding bore wall (110) comprises pumping conditioning fluid through an inner tubing (10) located within the bore-lining tubing (20) and into a portion of the well bore containing the bore-lining tubing to affect the temperature of the portion of the well bore containing the bore-lining tubing. The annulus (50) between the bore-lining tubing (20) and the surrounding bore wall (110) is at least partially filled with settable material (54). The affected temperature of the portion of the well bore containing the bore-lining tubing influences the setting of the settable material. For example, heating the bore may accelerate setting of the material, while cooling the bore may retard setting of the material.

Abstract: A well construction method, and corresponding apparatus, in which a drilled bore (106) is lined with a plurality of successively smaller diameter sections of bore-lining tubing includes at least one casing (108, 110, 112) and at least one liner (120). The well construction method comprises: drilling a final section of a bore (106) to intersect a hydrocarbon-bearing formation (130); providing a shoe (134) at a distal end of a liner and a running tool (150) at a proximal end of the liner, and coupling an inner string (140) between the shoe (134) and the miming tool (150); running the liner (120) into the final section of the bore (106) such that the liner extends into the hydrocarbon-bearing formation (130); pumping a settable material (116) from surface (104), through the inner string (140), and through the shoe (134) to at least partially fill an outer annulus (114) surrounding the liner (120); and retrieving the inner string (140) and the running tool (150).

Abstract: Downhole apparatus comprises: a tubular body for mounting on an inner tubing string (10); a first flow port (24); a second flow port (12a); and a connector (68) associated with the tubular body (10) and operable to at least one of engage with and disengage from a lower end (22) of a bore-lining tubing string (20). The apparatus has a first configuration in which the first flow port (24) is open and the second flow port (12a) is closed, whereby a settable material (54) may be pumped in a first direction (56) downwards through the tubular body, through the connector, and through the first flow port, and a second configuration in which the first flow port (24) is closed and the second flow port (12a) is open, whereby a fluid may be pumped in the first direction (58) downwards through the tubular body (10), exit the tubular body through the second flow port (12a), and then flow in a second direction upwards and externally of the tubular body.

Abstract: A system for facilitating the transmission of rotational torque through a tool when the tool is in tension but allowing free rotation without torque transmission when the tool is in compression and stroked partially or fully closed.