30 C.F.R. § 250.721
(a) You must test each casing string that extends to the wellhead according to the following table:
| Casing type | Minimum test pressure |
|---|---|
| (1) Drive or Structural, | Not required. |
| (2) Conductor, excluding subsea wellheads, | 250 psi. |
| (3) Surface, Intermediate, and Production, | 70 percent of its minimum internal yield. |
(e) If you plan to produce a well, you must:
(g) You must perform a negative pressure test on all wells that use a subsea BOP stack or wells with mudline suspension systems.
(6) If you have any indication of a failed negative pressure test, such as, but not limited to, pressure buildup or observed flow, you must immediately investigate the cause. If your investigation confirms that a failure occurred during the negative pressure test, you must: