Regulatory Citation(s):
78.85. Cementing
standards.
(a)
When cementing surface casing or coal protective casing, the operator shall use
cement that meets or exceeds the ASTM International C 150, Type I, II, or III
Standard or API Specification 10. The cement
must also:
(5) Prevent gas flow in the annulus. In areas of known shallow gas producing
zones, gas block additives and low fluid loss slurries shall be used.
Question:
A well service company contacted the
Department concerning the use of gas block additives and low fluid loss
slurries to prevent annular flow in areas of known shallow gas producing
zones. If the blend they use prevents
annular flow without using "gas block" additives, is the mix design
recognized as meeting the requirement? Is
there a performance demonstration that must be executed to demonstrate that the
blend meets this standard?
Response:
If the specific cement blend,
or mix design, is formulated to prevent gas flow in the annulus, then in
concept it could meet the substantive requirement of the referenced citation.
However, information from the well service company that details how the blend
accomplishes the gas blocking function should be requested.
There is currently no written
"performance standard" to demonstrate that a specific blend meets
this regulatory requirement, but in practice a performance standard would be
known cement jobs where the blend was used and achieved surface returns while
also successfully preventing the occurrence of annular flow attributable to the
failure of the cement to prevent gas intrusion/cutting.