Systems and methods for storing materials in earthen subterranean formations

A method for storing materials in an earthen subterranean formation, the method comprising:

• (a) forming a wellbore extending vertically from a terranean surface into the subterranean formation, the wellbore extending from an uphole end at the terranean surface to a longitudinally opposing downhole end;
• (b) installing a casing string in the wellbore whereby the casing string is cemented in place in the wellbore;
• (c) installing tubing within a central passage of the casing string whereby an annulus is formed between the casing string and the tubing;
• (d) injecting a solvent from the terranean surface into the wellbore through a central passage of the tubing;
• and
• (e) circulating salt from the wellbore to the terranean surface through the annulus in response to (d) to form a subterranean storage chamber in a salt deposit of the subterranean formation that is fluidically connected to the wellbore, the storage chamber at least partially filled with brine and having a lateral width that exceeds a vertical height of the storage chamber.

A method for storing materials in an earthen subterranean formation, the method comprising:

• (a) forming a wellbore extending vertically from a terranean surface into the subterranean formation, the wellbore extending from an uphole end at the terranean surface to a longitudinally opposing downhole end;
• (b) installing a casing string in the wellbore whereby the casing string is cemented in place in the wellbore;
• (c) installing an outer tubing within a central passage of the casing string whereby an outer annulus is formed between the casing string and the outer tubing;
• (d) installing an inner tubing within a central passage of the outer tubing whereby an inner annulus is formed between the outer tubing and the inner tubing;
• (e) injecting a solvent from the terranean surface into the wellbore through a central passage of the inner tubing;
• (f) circulating salt from the wellbore to the terranean surface through the inner annulus in response to (d) to form a subterranean storage chamber in a salt deposit of the subterranean formation that is fluidically connected to the wellbore, the storage chamber being at least partially filled with brine;
• (g) injecting a protective fluid from the terranean surface into the wellbore through the outer annulus to form a protective blanket of the protective fluid over a surface of the solvent contained in the storage chamber thereby preventing contact between the brine and the casing string;
• and
• (h) controlling a ratio of a volume of the solvent and a volume of the protective fluid injected into the wellbore to form the storage chamber with a predefined form factor.