Method for developing cavities in salt or other soluble rock

Claim 1

A METHOD OF FORMING SHAPED UNDERGROUND RESERVOIRS IN SOLUBLE-ROCK FORMATIONS, THE SAID METHOD COMPRISING: DRILLING A WELL THROUGH AN OVERBURDEN AND INTO A SOLUBLE-ROCK FORMATION; CEMENTING CASTING IN THE WELL, THE CASING SEAT BEING LOCATED AT A POINT BETWEEN A SUBSTANTIAL DISTANCE ABOVE, AND A SUBSTANTIAL DISTANCE BELOW. THE TOP OF THE SOLUBLE-ROCK FORMATION; INTRODUCING A TUBING STRING INTO THE CASED WELL AND RUNNING IT TO A SUBSTANTIAL DEPTH BELOW THE OPEN BOTTOM END OF THE SAID CASING; RUNNING ANOTHER TUBING STRING INTO THE WELL TO AN EVEN GREATER DEPTH; PUMPING A SEALING LIQUID, THAT IS RELATIVELY A NON-SOLVENT WITH RESPECT TO THE SOLUBLE ROCK FORMATION, INTO THE WELL AND PERMITTING THE SEALING LIQUID TO FLOW INTO OPEN HOLE BELOW THE CASING AND RISE UP AROUND THE CASTING; PUMPING A SOLVENT THAT IS IMMISCIBLE WITH AND HEAVIER THAN THE SEALING LIQUID DOWN THROUGH. ONE OF THE SAID TUBING STRINGS; INTRODUCING THE SOLVENT INTO THE WELL AND THUS BRINGING IT INTO CONTACT WITH THE SOLUBLE-ROCK FORMATION AND DISSOLVING ROCK OF THE SAID FORMATION; FORCING A SOLUTION OF THE ROCK IN THE SOLVENT UPWARDLY TO THE SURFACE THROUGH THE OTHER OF THE SAID TUBING STRINGS; AFTER A PERIOD IN WHICH A CAVITY OF A PREDETERMINED CAPACITY AND APPROXIMATE LATERAL DIMENSION HAS BEEN EXCAVATED BY SAID DISSOLVING. INTRODUCING ADDITIONAL SEALING LIQUID INTO THE WELL AND THUS LOWERING THE SEAL THAT IS FORMED BY THE SEALING LIQUID; ALSO LOWERING THE TUBING STRINGS IN THE WELL AND REPEATING THE DISSOLUTION PROCESS UNTIL ANOTHER, LOWER CAVITY OF A PREDETERMINED CAPACITY AND APPROXIMATE LATERAL DIMENSION HAS BEEN FORMED; AND CONTINUING A REPETITION OF THE FOREGOING STEPS WHILE VARYING THE PERIOD OF DISSOLVING TO OBTAIN CAVITIES OF PREDETERMINED APPROXIMATE LATERAL DIMENSION UNTIL A SHAPED RESERVOID HAS BEEN FORMED.

Claim 2

A METHOD OF FORMING SHAPED UNDERGROUND RESERVOIRS IN SOLUBLE-ROCK FORMATIONS, THE SAID METHOD COMPRISING: DRILLING A WELL THROUGH AN OVERBURDEN AND INTO A SOLUBLE-ROCK FORMATION; CEMENTING CASTING IN THE WELL, THE CASING SEAT BEING LOCATED AT A POINT BETWEEN A SUBSTANTIAL DISTANCE ABOVE, AND A SUBSTANTIAL DISTANCE BELOW. THE TOP OF THE SOLUBLE-ROCK FORMATION; INTRODUCING A TUBING STRING INTO THE CASED WELL AND RUNNING IT TO A SUBSTANTIAL DEPTH BELOW THE OPEN BOTTOM END OF THE SAID CASING; RUNNING ANOTHER TUBING STRING INTO THE WELL TO AN EVEN GREATER DEPTH; PUMPING A SEALING LIQUID, THAT IS RELATIVELY A NON-SOLVENT WITH RESPECT TO THE SOLUBLE ROCK FORMATION, INTO THE WELL AND PERMITTING THE SEALING LIQUID TO FLOW INTO OPEN HOLE BELOW THE CASING AND RISE UP AROUND THE CASTING; PUMPING A SOLVENT THAT IS IMMISCIBLE WITH AND HEAVIER THAN THE SEALING LIQUID DOWN THROUGH. ONE OF THE SAID TUBING STRINGS; INTRODUCING THE SOLVENT INTO THE WELL AND THUS BRINGING IT INTO CONTACT WITH THE SOLUBLE-ROCK FORMATION AND DISSOLVING ROCK OF THE SAID FORMATION; FORCING A SOLUTION OF THE ROCK IN THE SOLVENT UPWARDLY TO THE SURFACE THROUGH THE OTHER OF THE SAID TUBING STRINGS; AFTER A PERIOD IN WHICH A CAVITY OF A PREDETERMINED CAPACITY AND APPROXIMATE LATERAL DIMENSION HAS BEEN EXCAVATED BY SAID DISSOLVING. INTRODUCING ADDITIONAL SEALING LIQUID INTO THE WELL AND THUS LOWERING THE SEAL THAT IS FORMED BY THE SEALING LIQUID; ALSO LOWERING THE TUBING STRINGS IN THE WELL AND REPEATING THE DISSOLUTION PROCESS UNTIL ANOTHER, LOWER CAVITY OF A PREDETERMINED CAPACITY AND APPROXIMATE LATERAL DIMENSION HAS BEEN FORMED; AND CONTINUING A REPETITION OF THE FOREGOING STEPS WHILE VARYING THE PERIOD OF DISSOLVING TO OBTAIN CAVITIES OF PREDETERMINED APPROXIMATE LATERAL DIMENSION UNTIL A SHAPED RESERVOID HAS BEEN FORMED.