Dual end firing explosive column tools and methods for selectively expanding a wall of a tubular

1. A method of selectively expanding at least a portion of a wall of a tubular via an expansion tool, comprising:

assembling the expansion tool comprising a plurality of bi-directional boosters;

arranging a predetermined number of explosive pellets in a serially-arranged column between the plurality of bi-directional boosters;

positioning said expansion tool within the tubular; and

detonating the plurality of bi-directional boosters to simultaneously ignite opposing ends of the serially-arranged column to form two shock waves that collide to create an amplified shock wave that travels radially outward to impact the tubular at a first location and expand said at least a portion of the wall of the tubular radially outward without perforating or cutting through said at least a portion of the wall, to form a protrusion of the tubular at said at least a portion of the wall,

wherein the protrusion extends into an annulus adjacent an outer surface of the wall of the tubular.

2. The method according to claim 1 , wherein formation of the protrusion causes the at least a portion of the wall that forms the protrusion to be work-hardened so that the at least a portion of the wall forming the protrusion has a greater yield strength than other portions of the wall that are adjacent the protrusion.

3. The method according to claim 1 , further comprising providing a sealant onto said protrusion.

4. The method according to claim 3 , wherein the sealant is cement.

5. The method according to claim 3 , further comprising:

expanding the tubular at a second location spaced from the first location in a direction parallel to an axis of the expansion tool to create a pocket outside the tubular between the first location and second the location, wherein the sealant is in the pocket.

6. A method of selectively expanding at least a portion of a wall of a tubular via an expansion tool, comprising:

determining a hydrostatic pressure bearing on the tubular;

assembling the expansion tool comprising a plurality of bi-directional boosters;

selecting a predetermined number of explosive pellets based at least in part on the hydrostatic pressure;

arranging the predetermined number of explosive pellets in a serially-arranged column between the plurality of bi-directional boosters;

positioning said expansion tool within the tubular; and

detonating the bi-directional boosters to simultaneously ignite opposing ends of the serially-arranged column to form two shock waves that collide to create an amplified shock wave that travels radially outward to impact the tubular at a first location and expand said at least a portion of the wall of the tubular radially outward without perforating or cutting through said at least a portion of the wall, to form a protrusion of the tubular at said at least a portion of the wall,

wherein the protrusion extends into an annulus adjacent an outer surface of the wall of the tubular.

7. The method according to claim 6 , wherein the predetermined number of explosive pellets is further based on at least one of:

a material of the tubular;

a thickness of the wall of the tubular;

an inner diameter of the tubular;

an outer diameter of the tubular; and

a size of the protrusion to be formed in the wall of the tubular.

8. The method according to claim 6 , wherein the explosive pellets are serially aligned along an axis of the expansion tool.

9. The method according to claim 6 , wherein the annulus is between an outer surface of the wall of the tubular and an inner surface of a wall of another tubular.

10. The method according to claim 6 , wherein the annulus is between an outer surface of the wall of the tubular and a formation of a wellbore containing the tubular.

11. The method according to claim 6 , wherein the expansion tool comprises a guide tube, and the guide tube comprises the plurality of bi-directional boosters and the predetermined number of explosive pellets.