BOREHOLE PIEZOELECTRIC SOURCE FOR HIGH RESOLUTION SEISMIC APPLICATIONS

THE U.S. HAS AN ESTIMATED 327 BILLION BARRELS OF OIL IN EXISTING PRODUCTION FIELDS WHICH REMAINS IN PLACE EVEN AFTERPRIMARY AND SECONDARY RECOVERY TECHNIQUES HAVE BEEN EMPLOYED. HIGH RESOLUTION BOREHOLE-TO-BOREHOLE SEISMIC TOMOGRAPHY CAN PROVIDE THE INFORMATION NEEDED TO LOCATE THESE UNPRODUCED REGIONS THROUGH THE IDENTIFICATION OF SUBTLE GEOLOGIC ANOMALIES AND CAN BE USED TO ASSESS THE PROGRESS OF CERTAIN PRODUCTION STRATEGIES. HOWEVER, ADVANCES IN BOTH DATA ACQUISITION HARDWARE AND DATA PROCESSING ARE REQUIRED BEFORE HIGH RESOLUTION IMAGES ARE PRACTICAL BETWEEN OIL WELL BOREHOLES SEPARATED SEVERAL THOUSAND FEET. THIS PROJECT INVOLVES THE RESEARCH AND DEVELOPMENT OF AN INNOVATIVE FLUID-COUPLED SEISMIC SOURCE DESIGN WHICH OVERCOMES MANY OF THE DISADVANTAGES OF EXISTING PIEZOELECTRIC SEISMIC SOURCES. THE NEW SOURCE HAS A LOWER OPERATING FREQUENCY CAPABILITY APPROACHING 50 HZ, IS EFFICIENT, IS MORE SUITABLE FOR BOREHOLE APPLICATIONS, AND IS EXPECTED TO OPERATE AT BOREHOLE TEMPERATURES APPROACHING 200 DEGREES CENTIGRADE. PHASE I OF THE PROJECT WILL PROVE THE FEASIBILITY OF THE BOREHOLE PIEZOELECTRIC SEISMIC SOURCE THROUGH A LABORATORY AND FIELD STUDY AIMED AT DEFINING THE PIEZOELECTRIC SOURCE TRANSDUCER PERFORMANCE CHARACTERISTICS THROUGH FREE FIELD ACOUSTIC AND BOREHOLE-TO-BOREHOLE SEISMIC MEASUREMENTS. OF SPECIFIC INTEREST ARE THE SOURCE TRANSMISSION PROPERTIES SUCH AS: (1) USABLE BANDWIDTH, (2) SOURCE BEHAVIOR OVER THIS BAND, AND (3) THE PILOT WAVEFORM TO BE UTILIZED IN CORRELATION OF THE SOURCE. THIS BOREHOLE PIEZOELECTRIC SOURCE WILL BE CHARACTERIZED FOR EFFICIENT HIGH DUTY-CYCLE SWEEP EXCITATIONS. ITS PILOT SIGNAL CHARACTERISTICS WILL BE SUITABLY DEFINED SO THAT IT CAN BE PROPERLY CORRELATED TO PRODUCE A HIGH QUALITY KLAUDER WAVELET.