Process for temporarily and selectively sealing a well

Claim 1

A PROCESS FOR SELCTIVELY ISOLATING THE LESS PERMEABLE STREAKS FROM THE MORE PERMEABLE STREAKS OF A SUBTERRANEAN GEOLOGICAL FORMATION TRAVERSED BY A BOREHOLE, WHICH COMPRISE SIMULTANEOUSLY FORCING INTO SAID LESS PERMEABLE AND MORE PERMEABLE STREAKS AT A SUPERATMOSPHERIC PRESSURE, A LIQUID MIXTURE OF A LIQUEFIED, NORMALLY GASEOUS REFRIGERANT AND A SEALANT MATERIAL HAVING A MELTING POINT SUFFICIENTLY BELOW THE NORMAL TEMPERATURE OF THE FORMATION BEING TREATED WHEREBY SAID SEALANT MATERIAL IS SUBSTANTIALLY COMPLETELY IN THE LIQUID STATE AT NORMAL FORMATION TEMPERATURE, SAID PRESSURE BEING SUFFICIENT TO MAINTAIN SAID LIQUEFIED REFRIGRANT IN THE LIQUID STATE, REDUCING SAID PRESSURE WHEREBY SAID REFRIGERANT IS VAPORIZED THEREBY COOLING SAID LESS PERMEABLE AND MORE PERMEABLE STREAKS TO A TEMPERATURE SUBSTANTIALLY BELOW THE MELTING POINT OF SAID SEALANT MATERIAL AND SOLIDIFYING SAID SEALANT WITHIN SAID STREAKS TO EFFECT THE SEALING THEREOF, AND SHUTTING-IN SAID BOREHOLE FOR A TIME SUFFICIENT FOR THE TEMPERATURE OF THE LESS PERMABLE STREAKS TO INCREASE TO A TEMPERATURE IN EXCESS OF THE MELTING POINT OF SAID SEALANT BY NATURAL HEAT CONDUCTION WITHIN SAID FORMATION WHEREBY THE SEALANT IN SAID LESS PERMEABLE STEAKS BECOMES LIQUID.