SPECIAL LOGGING PROCEDURES FOR H₂S SITES

The following guidelines should be used unless otherwise instructed by the offshore installation manager:

• Maintain circulation while wireline tools are run into and out of the hole.
• Control wireline speeds to prevent swabbing H₂S fluids into the drill string from the well bore.
• Stop the tool above the top of the BHA once sampling or measurements are completed and the wireline tool(s) is/are retrieved inside the BHA.
• Pump three volumes of fluid (equal to the volume of fluid required to fill the inside of the BHA) to clear any H₂S-rich fluid that may have been swabbed into the BHA as the tool was pulled inside it.

See "Handling Downhole and Logging Tools at Various Locations" for additional safety information. Do not use excessive flow rates that may be sufficient to fail cablehead weak points and pump the wireline tools off the wireline (this has happened in the past). Components that are not designed for operation in H₂S and CO₂ environments are susceptible to sulfide and stress corrosion cracking. The cracking may occur downhole or at the surface over relatively short periods of time.