Welltest 103: Acoustic Well Sounder Surveys
Application of the #AWS for oil well pressure build-up surveys is well documented and avoids pulling rods and pump. Sonic surveys are also useful in a variety of other #welltest circumstances, including clean-up operations, gas (#LNG) well testing, and surface casing vent tests. Acoustic surveys can be utilized in virtually any wellbore configuration: shots down an annulus with jointed, coiled, seamless, or endless tubing installed; casing shots only (no tubing installed); or shots inside tubing (jointed or coiled).
The Amoco Bigoray 08–08 casing failure and blowout taught us the perils of using blank gun powder charges to produce the acoustic impulse. Air trapped in the annulus created a volatile situation that turned catastrophic when the 12 gauge blank shot was fired during a ‘routine’ AWS survey.
Compressed nitrogen (N2) or carbon dioxide (CO2) are inert and the only way to go for safety. While everybody still refers to the acoustic impulse as a ‘shot’ please do not infer this to mean gun powder—always use a gas gun to generate the energy impulse or sound wave.
