EVALUATION OF WELL LOG DATA FOR DETERMINATION OF AIR AND/OR GAS FILLED POROSITY

A PHYSICAL PROPERTY OF EARTH FORMATIONS THAT STRONGLY INFLUENCES THE RATE OF ATTENUATION OF A SHOCK WAVE IS THE BULK VOLUME OF AIR OR GAS ENTRAINED IN THE POROSITY. AS A RESULT, THE ACCURATE DETERMINATION OF THIS GAS VOLUME IS IMPORTANT FOR PREDICTING THE EFFECT OF A SHOCK WAVE ON SUBSURFACE STRUCTURES. THE OIL AND GAS INDUSTRY HAS USED GEOPHYSICAL WELL LOGS FOR YEARS TO IDENTIFY AND EVALUATE THE VOLUME OF OIL AND GAS IN SUBSURFACE FORMATIONS. IN THE PAST, THE TECHNIQUES UTILIZED BY THE OIL AND GAS INDUSTRY HAS NOT BEEN OF SUFFICIENT ACCURACY FOR USE IN SHOCK ATTENUATION STUDIES. RECENT DEVELOPMENTS IN LOG MEASUREMENTS, PREPROCESSING, QUALITY CONTROL, DATA INTEGRATION, AND MODELING HAS GREATLY IMPROVED THE ACCURACY OF DETERMINING LOW VOLUMES OF GAS AT LOW POROSITIES. WELL LOG DATA FROM AN AREA IN THE ILLINOIS BASIN WILL BE EVALUATED TO DETERMINE IF THESE RECENT DEVELOPMENTS ARE OF SUFFICIENT MAGNITUDE THAT THE RESULTS WILL BE USEFUL TO DNA.