Process for sealing porous formations

Claim 1

THE PROCESS FOR SEALING A POROUS UNDERGROUND FORMATION WHICH IS PERMEABLE TO WATER AND IS AT A TEMPERATURE T OF FROM ABOUT 15* C. TO ABOUT 90* C. WHICH COMPRISES FORCING INTO THE PORES OF SAID FORMATION A FRESHLY PREPARED ANYHYDROUS SOLUTION HAVING A BROOKFIELD VICOSITY OF UP TO 100 CPS. AT 25* C. AND WHICH SOLUTION CONSISTS ESSENTIALLY OF (1) AT LEAST ABOUT 40% BY WEIGHT OF A POLYISOCYANATE COMPOSITION CONTAINING AT LEAST 6% BY WEIGHT OF FREE ISOCYANATE GROUPS AS THE SOLE GROUPS REACTIBLE WITH ALCOHOLIC HYDROXYL GROUPS, SAID POLYISOCYANATE COMPOSITION CONSISTING OF AT LEAST ONE MEMBER OF THE CLASS CONSISTING OF AROMATIC POLYISOCYANATES AND REACTION PRODUCTS OF AN AROMATIC POLYISOCYANATE WITH AN ALIPHATIC POLYHYDROXY COMPOUND HAVING A MOLECULAR WEIGHT OF FROM ABOUT 62 TO ABOUT 4000 AND CONTAINING AT LEAST 2 ALCOHOLIC HYDROXYL GROUPS AND IN WHICH THE SOLE GROUPS REACTIBLE WITH ISOCYANATE GROUPS ARE HYDROXYL GROUPS, EACH MOLECULE OF SAID REACTION PRODUCTS CONTAINING AT LEAST 2 FREE ISOCYANATE GROUPS; (2) FOR EACH 100 PARTS OF SAID POLYISOCYANATE COMPOSITION FROM ABOUT 0.32 PART TO 0.32+(90.0-T) (0.0372) PARTS BY WEIGHT OF A 2,4,6-TRIS(DIALKYLAMINOMETHYL) PHENOL IN WHICH EACH ALKYL RADICAL CONTAINS 1-8 CARBON ATOMS AND THE SUM OF SAID ALKYL RADICALS CONTAINS 6-24 CARBON ATOMS, THE AMOUNT OF SAID PHENOL BEING INSUFFICIENT TO CAUSE THE VICOSITY OF THE SOLUTION TO RISE ABOVE 100 CPS. AT 25* C. IN 30 MINUTES; AND (3) AN INERT LIQUID ORGANIC SOLVENT HAVING FLASH POINT OF AT LEAST 40* C. IN AN OPEN CUP AT ATMOSPHERIC PRESSURE AND WHICH IS A SOLVENT FOR BOTH THE POLYISOCYANATE COMPOSITION AND THE PHENOL; AND MAINTAINING THE SOLUTION IN THE PORES OF THE FORMATION UNTIL IT HAS SOLIDIFIED.