Subterranean recovery process by combustion

Claim 1

IN THE PROCESS FOR THE RECOVERY OF HYDROCARBON MATERIAL FROM A SUBTERRANEAN FORMATION CONTAINING HYDROCARBONS AND HAVING AN INPUT WELL LEADING THERETO AND AT LEAST ONE OUTPUT WELL LEADING THEREFROM WHEREIN COMBUSTION OF HYDROCARBON MATERIAL WITHIN SAID SUBTERRANEAN FORMATION IS INITIATED, COMBUSTION SUPPORTING GAS CONTAINING A COMBUSTION SUPPORTING MEDIUM IS PASSED THROUGH SAID SUBTERRANEAN FORMATION THROUGH SAID INPUT WELL IN THE DIRECTION OF AN OUTPUT WELL AND AS A RESULT THEREOF A FLAME FRONT PRECEDED BY COMBUSTION GAS AND HYDROCARBON PRODUCTS RECOVERABLE FROM AN OUTPUT WELL MIGRATE THROUGH SAID SUBTERRANEAN FORMATION FROM SAID INPUT WELL IN THE DIRECTION OF SAID OUTPUT WELL AND GAS ISSUES FROM SAID SUBTERRANEAN FORMATION THROUGH SAID OUTPUT WELL, THE STEPS COMPRISING DETERMINING THE TIME REQUIRED FOR SAID COMBUSTION SUPPORTING GAS TO PASS THROUGH SAID SUBTERRANEAN FORMATION FROM SAID INPUT WELL TO AN OUTPUT WELL, PASSING INTO SAID SUBTERRANEAN FORMATION THROUGH SAID INPUT WELL IN ADDITION TO SAID COMBUSTION SUPPORTING GAS IN KNOWN AMOUNT WITH RESPECT TO SAID COMBUSTION SUPPORTING GAS A GASEOUS, OXIDIZABLE MATERIAL HAVING AS A CONSTITUENT ELEMENT THEREOF A HEAVY ISOTOPE OF HYDROGEN IN WHICH GASEOUS, OXIDIZABLE MATERIAL THE RATIO OF SAID HEAVY ISOTOPE OF HYDROGEN TO PROTIUM IS GREATER THAN IN HYDROGEN NOT TREATED TO INCREASE THIS RATIO WHEREBY SAID GASEOUS, OXIDIZABLE MATERIAL IN ADMIXTURE IN KNOWN AMOUNT WITH SAID COMBUSTION SUPPORTING GAS ADVANCES THROUGH SAID SUBTERRANEAN FORMATION FROM SAID INPUT WELL IN THE DIRECTION OF SAID OUTPUT WELL, ANALYZING AT A TIME SUBSEQUENT TO PASSING SAID GASEOUS, OXIDIZABLE MATERIAL INTO SAID SUBTERRANEAN FORMATION AND EQUAL TO SAID TIME REQUIRED FOR GAS TO PASS THROUGH SAID SUBTERRANEAN FORMATION FROM SAID INPUT WELL TO SAID OUTPUT WELL GAS ISSUING FROM SAID OUTPUT WELL FOR THE AMOUNT WITH RESPECT TO SAID GAS OF SAID HEAVY OF HYDROGEN WHEREBY INFORMATION CONCERNING THE PRESENCE OF SAID FLAME FRONT IN THE PATH OF GAS FLOW BETWEEN SAID INPUT WELL AND SAID OUTPUT WELL IS OBTAINED, AND THEREAFTER CHANGING THE RATE OF FLOW OF COMBUSTION SUPPORTING MEDIUM THROUGH SAID SUBTERRANEAN FORMATION BETWEEN SAID INPUT WELL AND SAID OUTPUT WELL WHEREBY CHANGE OF MIGRATION OF SAID FLAME FRONT IN SAID SUBTERRANEAN FORMATION IS EFFECTED.