Editorial Note on Part 250
Editorial Note: Nomenclature changes to part 250 appear at 77 FR 50891, Aug. 22, 2012.

§ 250.420 What well casing and cementing requirements must I meet? You must case and cement all wells. Your casing and cementing programs must meet the applicable requirements of this subpart and of subpart G of this part. ( a ) *Casing and cementing program requirements.* Your casing and cementing programs must: ( 1 ) Properly control formation pressures and fluids;
( 2 ) Prevent the direct or indirect release of fluids from any stratum through the wellbore into offshore waters;
( 3 ) Prevent communication between separate hydrocarbon-bearing strata;
( 4 ) Protect freshwater aquifers from contamination;
( 5 ) Support unconsolidated sediments;
( 6 ) Provide adequate centralization consistent with the guidelines of API Standard 65—Part 2 (as incorporated by reference in § 250.198); and
( 7 ) ( i ) Include a certification signed by a registered professional engineer that the casing and cementing design is appropriate for the purpose for which it is intended under expected wellbore conditions, and is sufficient to satisfy the tests and requirements of this section and § 250.423. Submit this certification with your APD (Form BSEE-0123).
( ii ) You must have the registered professional engineer involved in the casing and cementing design process.
( iii ) The registered professional engineer must be registered in a state of the United States and have sufficient expertise and experience to perform the certification.
( b ) *Casing requirements.* ( 1 ) You must design casing (including liners) to withstand the anticipated stresses imposed by tensile, compressive, and buckling loads; burst and collapse pressures; thermal effects; and combinations thereof.
( 2 ) The casing design must include safety measures that ensure well control during drilling and safe operations during the life of the well.
( 3 ) On all wells that use subsea BOP stacks, you must include two independent barriers, including one mechanical barrier, in each annular flow path (examples of barriers include, but are not limited to, primary cement job and seal assembly). For the final casing string (or liner if it is your final string), you must install one mechanical barrier in addition to cement to prevent flow in the event of a failure in the cement. A dual float valve, by itself, is not considered a mechanical barrier. These barriers cannot be modified prior to or during completion or abandonment operations. The BSEE District Manager may approve alternative options under § 250.141. You must submit documentation of this installation to BSEE in the End-of-Operations Report (Form BSEE-0125).
( 4 ) If you need to substitute a different size, grade, or weight of casing than what was approved in your APD, you must contact the District Manager for approval prior to installing the casing.
( c ) Cementing requirements . ( 1 ) You must design and conduct your cementing jobs so that cement composition, placement techniques, and waiting times ensure that the cement placed behind the bottom 500 feet of casing attains a minimum compressive strength of 500 psi before drilling out the casing or before commencing completion operations. (If a liner is used refer to § 250.421(f)).
( 2 ) You must use a weighted fluid during displacement to maintain an overbalanced hydrostatic pressure during the cement setting time, except when cementing casings or liners in riserless hole sections.
[76 FR 64462, Oct. 18, 2011, as amended at 77 FR 50892, Aug. 22, 2012; 81 FR 26018, Apr. 29, 2016; 84 FR 21973, May 15, 2019]