A closed-loop testing system was applied to test wells with ultrahigh-H₂S content—without release to atmosphere. The system reliably handled the wells without any flow limitations or H₂S exposure, meeting the operator's objectives.

Testing ultrahigh-H₂S wells often presents technical and HSE risks. Reservoirs with high H₂S content can’t be flowed using an industry-standard well test package. For an operator in the Middle East, high H₂S conflicted with testing objectives, causing the operator to enforce strict limitations during flowback operations.

A previous attempt to start the flowback required shutting in the well. The operator needed a solution to deliver the well within the highest safety standard guidelines. Additionally, the operator wanted to obtain representative well test data and prepare the well for production.

Sour wells, which were rarely able to be flowed back, can now be produced safely and reliably with the closed-loop testing system, handling production with ultrahigh H₂S content. Nine consecutive flowing days have been achieved so far from a previous 24-h maximum flow period. Well performance proved better than expected.^†

The system was applied to six ultrahigh-H₂S wells in total and produced without any flow limitations.

^† Standard conditions: 14.7 psi at 60 degF