APPARATUS, COMPUTER READABLE MEDIUM, AND PROGRAM CODE FOR EVALUATING ROCK PROPERTIES WHILE DRILLING USING DOWNHOLE ACOUSTIC SENSORS AND TELEMETRY SYSTEM

摘要

Apparatus (100), computer readable medium, and program code for identifying rock properties in real-time during drilling, are provided. An example of an embodiment of such an apparatus (100) includes a downhole sensor subassembly (102) connected between a drill bit (101) and a drill string (105), acoustic sensors (103) operably coupled to a downhole processor (104, 104'), a borehole telemetry system (302), downhole and surface data transmitting interfaces (111, 113), and a surface computer (124) operably coupled to the downhole data transmitting interface (301). The downhole processor (104, 104') is adapted to perform operations including receiving raw acoustic sensor data resulting from rotational contact of the drill bit (101) with rock, transforming the raw acoustic sensor data into the frequency domain, filtering the transformed data, and deriving acoustic characteristics (107) from the filtered data. The surface computer (124) is adapted to perform operations including deriving petrophysical properties (305) from the acoustic characteristics (107) directly or by utilizing a petrophysical properties evaluation algorithm (304, 304A, 304B),