Oil recovery

Claim 1

THE PROCESS OF RECOVERING OIL FROM A SUBTERRANEAN TAR SAND FORMATION PENETRATED BY AT LEAST ONE INPUT WELL AND AT LEAST ONE PRODUCTION WELL, WHICH PROCESS COMPRISES THE STEPS OF INTRODUCING THROUGH SAID INPUT WELL A DILUTE AQUEOUS ALKALINE SOLUTION CONTAINING BETWEEN ABOUT 0.0025 WT. PERCENT AND 1 WT. PERCENT OF AN ALKALI METAL HYDROXIDE AT LEAST A PORTION OF SAID ALKALINE SOLUTION BEING POSITIONED ADJACENT THE TAR SAND FORMATION SURROUNDING SAID INPUT WELL UNDER SUFFICIENT PRESSURE TO CREATE FRACTURES EXTENDING THROUGH SAID FORMATION BETWEEN SAID WELLS, CONTINUING THE INTRODUCTION OF SAID DILUTE AQUEOUS ALKALINE SOLUTION TO CAUSE IT TO FLOW THROUGH THE FRACTURES, TO EXTRACT THE OIL FROM THE SANDS AMD TO PRODUCE IN THE FORMATION AN OIL-IN-WATER EMULSION, PRODUCING SAID OIL-IN-WATER EMULSION FROM SAID PRODUCTION WELL, INTERRUPTING PERIODICALLY SAID INJECTION OF THE ALKALINE SOLUTION, PERIODICALLY INTERRUPTING SAID RECOVERY OF SAID EMULSION FROM SAID PRODUCTION WELL WHILE PERIODICALLY INJECTING THROUGH SAID PRODUCTION WELL AND INTO THE TAR SAND FORMATION A SLUG OF AQUEOUS ALKALINE SOLUTION CONTAINING BETWEEN ABOUT 0.0025 WT. PERCENT AND 1 WT. PERCENT OF AN ALKALI METAL HYDROXIDE, SAID SLUG OF SAID ALKALINE SOLUTION AIDING IN OPENING UP THE TAR SAND FORMATION ADJACENT TO THE OUTPUT WELL THEREBY AIDING THE FLOW OF THE OIL-CONTAINING EMULSION TO SAID OUTPUT WELL FROM WHICH IT IS RECOVERED AND THE OIL IS SEPARATED.