Recovery of hydrocarbon material from a subterranean

Claim 1

IN A PROCESS FOR THE RECOVERY OF HYDROCARBON MATERIAL FROM A SUBTERRANEAN FORMATION CONTAINING HYDROCARBON MATERIAL WHEREIN SAID FORMATION IS PENETRATED BY A PLURALITY OF WELLS, SAID WELLS FORMING A PLURALITY OF SIMILAR PATTERNS AND EACH OF SAID PATTERNS HAVING INPUT MEANS INCLUDING AT LEAST ONE INPUT WELL AND OUTPUT MEANS INCLUDING AT LEAST ONE OUTPUT WELL, AND A FLUID IS INJECTED UNDER PRESSURE FROM A COMPRESSOR MEANS INTO SAID FORMATION THROUGH AN INPUT MEANS OF A PATTERN AND SAID HYDROCARBON MATERIAL IS THEREBY DISPLACED FROM SAID FORMATION AND MOVED INTO THE DIRECTIN OF SAID OUTPUT MEANS OF SAID PATTERN FROM WHICH OUTPUT MEANS IT IS RECOVERED, THE STEPS FOR ESTABLISHING AND MAINTAINING SUBSTANTIALLY CONSTANT THE RATE OF INJECTION OF SAID FLUID INTO SAID FORMATION FROM SAID COMPRESSOR MEANS COMPRISING (1) INJECTING SAID FLUID UNDER PRESSURE FROM SAID COMPRESSOR MEANS INTO SAID FORMATION THROUGH THE INPUT MEANS OF A FIRST PATTERN AT A RATE SUFFICIENTLY HIGH TO DISPLACE SAID HYDROCARBON MATERIAL FROM SAID FORMATION AND MOVE SAID HYDROCARBON MATERIAL IN THE DIRECTION OF THE OUTPUT MEANS OF SAID FIRST PATTERN, (2) GRADUALLY INCREASING THE RATE OF INJECTION OF SAID FLUID THROUGH SAID INPUT MEANS OF SAID FIRST PATTERN, (3) DISCONTINUING INCREASE IN THE RATE OF INJECTION OF SAID FLUID VEFORE THE RATE AT WHICH SAID HYDROCARBON MATERIAL IS DISPLACED FORM SAID FORMATION EXCEEDS THE RATE AT WHICH THE ENTIRE AMOUNT OF SAID DISPLACED HYDROCARBON MATERIAL FROM SAID FIRST PATTERN CAN BE RECOVERED FRM SAID OUTPUT MEANS OF SAID PATTERN (4) THEREAFTER GRADUALLY DECREASING THE RATE OF INJECTION OF SAID FLUID THROUGH SAID INPUT MEANS OF SAID FIRST PATTERN,