TRANSPORTING MOBILITY CONTROL AGENTS TO HIGH PERMEABILITY THIEF ZONES

THIS RESEARCH PROJECT WILL DIRECTLY ADDRESS THE PROBLEM OF SWEEP IMPROVEMENT FOR ENHANCED OIL RECOVERY (EOR) PROCESSES. ONE OF THE MAJOR PROBLEMS IN CONDUCTING AN EFFICIENT EOR PROCESS IS THE CONTROL OF THE INJECTED FLUIDS. IN MOST FIELD APPLICATIONS OF MISCIBLE OR IMMISCIBLE SOLVENT DRIVES, SUCH AS CARBON DIOXIDE OR LIGHT HYDROCARBON FLOODS, THE PRESENCE OF RESERVOIR HETEROGENEITIES LEADS TO EARLY SOLVENT BREAKTHROUGH. BY OFFERING A PATH OF LEAST RESISTANCE, THE HIGH PERMEABILITY STREAKS OR THIEF ZONES TAKE THE BULK OF THE INJECTED SOLVENT, AND, AS A CONSEQUENCE, LARGE VOLUMES OF THE RESERVOIR OIL ARE LEFT UNSWEPT. REDIRECTING THE INJECTED SOLVENT SO THAT PREVIOUSLY UNSWEPT VOLUMES OF THE RESERVOIR CAN BE ACCESSED ALLOWS FOR ADDITIONAL OIL RECOVERY. THIS REQUIRES IN-DEPTH PLUGGING OF THESE HIGH PERMEABILITY STREAKS. THE EFFICACY OF THE DIVERTING PROCESS WOULD BE FURTHER INCREASED IF THE PLUGGING MECHANISM WAS IMPLEMENTED VIA THE INJECTED SOLVENT, AS THIS WOULD DELIVER THE PLUGGING AGENTS DIRECTLY TO THETHIEF ZONE TAKING THE SOLVENT. THE PHASE I INVESTIGATION ADDRESSES THAT ISSUE BY STUDYING A SIMPLE SCHEME WHEREBY A PLUGGING AGENT SOLUBLE IN THE INJECTED SOLVENT IS ADDED AT THE WELLHEAD. THE PLUGGING AGENT WILL COME OUT OF SOLUTION AFTER THE SOLVENT HAS PENETRATED SOME DISTANCE INTO THE RESERVOIR, AND THUS PLUG THE THIEF ZONE TAKING THE BULK OF THE SOLVENT.