ACOUSTIC GAS-KICK DETECTION WITH WELLHEAD SONAR

The capability to detect gas kicks (gas influxes into a borehole) quic kly as the borehole is being drilled is of the utmost importance for d rilling safety and efficiency. In this paper a novel kick-detection sy stem based on an acoustic pulse-echo technique is described. Computer simulations and full-scale experimental results show that this system can detect small gas influxes (typically < 1 bbl) at depths as great a s 16,400 ft. The system, which has surface-based equipment, functions irrespective of mud circulation.