Downhole apparatus and method for operations involving delivery and hardening of settable materials

A method of controlling a transition of a settable material in a downhole location from a fluid form to a solid form, the method comprising:

• providing a settable material having a temperature-related setting rate at which the settable material transitions from a fluid form to a solid form;
• delivering the settable material in the fluid form to at least partially fill an annulus of a bore;
• determining an axial thermal gradient profile of the bore and determining a related axial setting profile for the settable material in the annulus;
• and
• modifying the axial thermal gradient profile of the bore and thereby modifying the axial setting profile for the settable material in the annulus to provide different setting rates of the settable material at different axial locations in the annulus,
• wherein the delivering the settable material in the fluid form comprises delivering the settable material to first and second axial portions of the annulus in the bore;
• and wherein the modifying the axial thermal gradient profile of the bore comprises controlling the axial setting profile for the settable material in the annulus whereby the settable material in the first axial portion of the annulus transitions from the fluid form to the solid form at a different rate than the settable material in the second axial portion.

A method of controlling a transition of a settable material in a downhole location from a fluid form to a solid form, the method comprising:

• providing a settable material having a temperature-related setting rate at which the settable material transitions from a fluid form to a solid form;
• determining an optimal setting rate for the settable material to provide set material having optimal characteristics;
• delivering the settable material in the fluid form to at least partially fill an annulus of a bore;
• determining an axial thermal gradient profile of the bore and determining a related axial setting profile for the settable material in the annulus;
• and
• modifying the axial thermal gradient profile of the bore and thereby modifying the axial setting profile for the settable material in the annulus to provide the optimal setting for the settable material in the annulus,
• wherein the delivering the settable material in the fluid form comprises delivering the settable material to first and second axial portions of the annulus in the bore;
• and wherein the modifying the axial thermal gradient profile of the bore comprises controlling the axial setting profile for the settable material in the annulus whereby the settable material in the first axial portion of the annulus transitions from the fluid form to the solid form at a different rate than the settable material in the second axial portion.