43 C.F.R. § 3172.9 – Drill stem testing.

(a) Requirements. Initial opening of drill stem test tools shall be restricted to daylight hours unless specific approval to start during other hours is obtained from the authorized officer. However, drill stem tests (DSTs) may be allowed to continue at night if the test was initiated during daylight hours and the rate of flow is stabilized and if adequate lighting is available (i.e., lighting which is adequate for visibility and vapor-proof for safe operations). Packers can be released, but tripping shall not begin before daylight, unless prior approval is obtained from the authorized officer. Closed chamber DSTs may be accomplished day or night.
(b) Minimum standards for drill stem testing.
1. (1) A DST that flows to the surface with evidence of hydrocarbons shall be either reversed out of the testing string under controlled surface conditions, or displaced into the formation prior to pulling the test tool. This would involve providing some means for reserve circulation.
  Table 1 to § 3172.9(b)(1)
  Violation Corrective action Normal abatement period
  Major Contingent on circumstances and as specified by the authorized officer Prompt correction required.
2. (2) Separation equipment required for the anticipated recovery shall be properly installed before a test starts.
  Table 2 to § 3172.9(b)(2)
  Violation Corrective action Normal abatement period
  Major Install required equipment Prompt correction required.
3. (3) All engines within 100 feet of the wellbore that are required to “run” during the test shall have spark arresters or water-cooled exhausts.
  Table 3 to § 3172.9(b)(3)
  Violation Corrective action Normal abatement period
  Major Install required equipment Prompt correction required.