System and method for a slotted liner shoe extension

1. A method comprising:

injecting a thermally degradable material at a desired depth into a liner having a plurality of openings, wherein the liner is suspended below a cemented casing in a wellbore of a well in a subterranean formation, wherein the thermally degradable material has a density about equal to or less than a density of fluid in the wellbore, and wherein the thermally degradable material extrudes through a lower portion of the liner into an annulus between the liner and the wellbore to plug an open hole interval of the well, wherein the thermally degradable material does not flow downward into a deeper part of the well; and

circulating a cement into the liner above the thermally degradable material, wherein the cement extrudes through an upper portion of the liner into the annulus between the liner and the wellbore, displacing water from the wellbore and forming a solid cemented casing string, and wherein the cement is kept from sinking down the annulus between the liner and wellbore and separated from the deeper part of the well by the thermally degradable material.

2. The method of claim 1 , further comprising removing the cement and the thermally degradable material inside of the liner.

3. The method of claim 1 , wherein the thermally degradable material includes one or more of,

(a) a thermally degradable cement,

(b) a thermally degradable foamed cement;

(c) a thermally degradable particulate material, and

(d) a thermally degradable polymer including foamed polymer resin beads.

4. The method of claim 1 , wherein the thermally degradable material is injected into the liner over an isolation device.

5. The method of claim 4 , wherein the isolation device is one of a drillable packer, a cementing basket, and a bridge plug.

6. The method of claim 1 , wherein the thermally degradable material is balanced against the weight of the fluid in the wellbore.

7. The method of claim 1 , wherein the thermally degradable material degrades thermally and is removed from the wellbore as a liquid or as a solute in a wellbore.

8. The method of claim 1 , wherein the solid cemented casing string protects a permeable zone from fracturing during subsequent injection of the well.

9. The method of claim 1 , where the cement used is foamed to increase an upward movement and penetration into the annulus between the liner and the wellbore and to reduce a downward flow of the cement into the wellbore that is capable of damaging a desirable permeable zone.

10. The method of claim 1 , where the thermally degradable material is a foamed cement that degrades thermally, and wherein the foamed cement is one or more of a calcium aluminum cement, ammonium magnesium phosphate sorel cement, magnesium phosphate sorel cement or magnesium potassium phosphate sorel cement.

11. The method of claim 1 , where the openings are enlarged with a perforating gun to improve circulation of the thermally degradable material and the cement out into the annulus.

12. The method of claim 1 , wherein the plurality of openings include one or more of slots, perforations, and mesh.

13. The method of claim 1 , where the liner is a well screen.

14. The method of claim 1 , where the solid cemented casing string allows stimulation of a zone deeper than the cemented casing string requiring a higher stimulation pressure than a shallower zone.

15. The method of claim 1 , wherein the solid cemented casing string prevents production of undesirable fluids, and wherein the undesirable fluids are cold water in a hot geothermal well, or water, steam or CO2 in an oil or gas well.

16. The method of claim 1 , wherein the thermally degradable material is a thermally degrading particulate material selected from a group consisting of polyglycolic acid, polylactic acid, polyhydroxybutyrate, co-hydroxyvalerate, polybutylene succinate, polypropylene fumarate, polycaprolactone, polyethylene terephthalate, polyhydroxyalkanoate, polycarbonate, poly-paraphenylene terephthalamide, polyoxybenzylmethylenglycolanhydride, polyethylene and polypropylene.

17. The method of claim 16 , wherein the thermally degrading particulate material is circulated up the annulus between the liner and the wellbore and into a permeable zone behind the liner.

18. The method of claim 17 , wherein the thermally degrading particulate material in a first portion of the wellbore degrades while the thermally degrading particulate material remains in place in a second portion of the wellbore having a lower temperature than the first portion, allowing production from or injection into only the first portion of the well.

19. The method of claim 17 , wherein the thermally degrading particulate material is an inorganic material and is selected from a group comprising boehmite, sorel cement, magnesium sulfate sorel cement, magnesium chloride sorel cement, calcium aluminum cement, ammonium magnesium phosphate surd cement, magnesium phosphate sorel cement or magnesium potassium phosphate sorel cement, aluminum hydroxide, and magnesium oxide.

20. The method of claim 1 , wherein the displaced water exits the well through valves at a wellhead or is displaced into cracks, fractures, or a permeable zone of the well.

21. The method of claim 1 , further comprising selecting the thermally degrading material to degrade at a temperature of a first portion of the wellbore while remaining in place at a lower temperature of a second portion of the wellbore.