Abstract: A downhole method comprises expanding a patch member. The patch member may be employed in a method of sealing a wall of a bore. The sealing method may comprise: providing the patch member with a sealing material on an exterior surface; running the patch member into the bore in a smaller diameter first configuration; heating the sealing material to render the sealing material flowable; reconfiguring the patch member to a larger diameter second configuration; and hardening the sealing material to provide a seal between the exterior surface of the patch member and an inner surface of the bore.

Abstract: A method of sealing a subsurface bore comprises: locating a volume of thermite in the bore; locating a volume of alloy in the bore with the thermite; initiating reaction of the thermite to heat the alloy; and bringing the alloy to above the melting point of the alloy whereby the alloy flows and occludes the bore. The thermite may retain its initial form during or following reaction or may partially fluidise. The thermite may react to provide a platform that at least partially occludes the bore. The alloy may flow over a surface of the thermite.

Abstract: Methods and apparatus for forming platforms and flow control features in underground wells is described, using modified thermite reactions to form a ceramic plug in place. The reactive package is engineered to expand laterally, filling the well, and may be used to form a ceramic bridge plug, porous ceramic screen sections, or mitigate lost circulation of drilling fluids. These objectives are achieved through the design of the reactive package and through use of carefully chosen reaction additives that control the molten product rheology, solidification temperature, and pore generations and sustainment.