DEVELOPMENT OF AN EXPLORATION STRATEGY DESIGNED FOR IDENTIFYING REGIONS CAPABLE OF HIGH GAS UTILIZING THE OPEN-HOLE CAVITATION TECHNIQUE

THE REMARKABLE SUCCESS ACHIEVED FOR PRODUCING GAS FROM COAL SEAMS INTHE SAN JUAN BASIN CAN BE ATTRIBUTED LARGLEY TO UTILIZATION OF THE INNOVATIVE OPEN-HOLE CAVITATION (OHC) TECHNIQUE. NEARLY 70% OF THE SAN JUAN BASIN COALBED METHANE IS PRODUCED FROM OHC WELLS EVEN THOUGH THEY ONLY ACCOUNT FOR 20% OF THE PRODUCING COALBED METHANE WELLS. MOST OHC WELLS COMPLETED WITH OHCOUTPERFORM HYDRAULIC FRACTURED WELLS BY A FACTOR OF FIVE. OUTSIDE THE FAIRWAY, HYDRAULICALLY FRACTURED WELLS TYPICALLY OUTPERFORM OHC WELLS. THE PRODUCTION VARIABILITY IS RELATED TO REGIONAL CHANGES IN RESERVOIR CONDITIONS AS REFLECTED BY VARYING GEOLOGIC CHARACTERISTICS. THEGEOLOGICAL PARAMETERS LEADING TO SUCCESSFUL OHC WELLS HAVE BEEN INADEQUATELY STUDIED FOR PREDICTABILITY USING THE OHC TECHNIQUE OUTSIDE OF THE EXISTING CAVITY FAIRWAY. THE PLANNED RESEARCH IS DIRECTED TOWARDS RESOLVING THE GEOLOGIC SYSTEMS FAVORABLE TO ACHIEVING CAVITATION WITH INITIAL HIGH GAS RATES. PRELIMINAY PRODUCTION MAPPING SUGGESTSTHE CAVITATION FAIRWAY IS CHARACTERIZED BY A NORTHWEST TREND EXTENSIONAL FRACTURED ZONE WHICH HAS INTERSECTED COAL RESERVOIRS AT FULL ADSORPTIVE CAPACITY WITH FREE GAS IN THE FRACTURES. PHASE I WILL DELINEATE THE ORIGIN OF THIS UNIQUE SYSTEM BY (1) ESTABLISHING BASEMENT WRENCHFAULTING TECTONICS USING SEISMIC AND STRATIGRAPHIC MAPPING, (2) THERMAL MODELING TO HELP QUANTIFY ORIGIN OF HIGH GAS RETENTION AND TRAPPING MECHANISMS, AND (3) EXTENSIONAL, LOW STRESS SETTING, AND FRACTURING HYPOTHESIS TO BE SUPPORTED WITH SURFACE FRACTURE MAPPING USING REMOTE IMAGERY. IN PHASE II THEPREICTIVE MODEL CALIBRATED AGAINST THE PRODUCTION ANOMALY FAIRWY IN THE SAN JUAN BASIN WILL BE USED IN SCREENING OTHER COAL BASINS FOR REGIONS SUITABLE FOR THE OHCCOMPLETION TECHNIQUE.