Method of treating oil-productive subterranean formations

Claim 1

A PROCESS FOR THE TREATMENT OF A SUBTERRANEAN FORMATION PROVIDED WITH A WELL BOREHOLE LEADING THERETO FROM THE SURFACE OF THE EARTH, SAID FORMATION BEING PRODUCTIVE OF PETROLEUM OIL TO SAID WELL BOREHOLE AND CONTAINING AN OIL PHASE AND A WATER PHASE TO RENDER SAID FORMATION WATER WET AND TO INCREASE THE FLOW CAPACITY OF SAID FORMATION TO PETROLEUM OIL AND THE FLOW OF PETROLEUM OIL TO SAID WELL BOREHOLE COMPRISING PRELIMINARILY TREATING SAID FORMATION BY INTIALLY INJECTING A LIQUID CONSISTING OF A LIQUID HAVING PARTICULAR SOLUBILITY FOR PETROLEUM OIL AND PETROLEUM OIL DERIVARIVES INTO SAID FORMATION THROUGH SAID WELL BOREHOLE LEADING THERETO, THEREAFTER INJECTING A SOLVENT HAVING MUTUAL SOLUBILITY FOR OIL AND WATER INTO SAID FORMATION THROUGH SAID WELL BOREHOLE AND INJECTING LIQUID WATER INTO SAID FORMATION THROUGH SAID WELL BOREHOLE, AND THEREAFTER PRODUCING PETROLEUM OIL FROM SAID FORMATION THROUGH SAID WELL BOR HOLE AND RECOVERING THE PRODUCED PETROLEUM OIL FROM SAID WELL BOREHOLE.