Structure on which the derrick sits. The substructure may provide space for wellhead and well control equipment.
Source: API RP 54, Recommended Practice for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations, Third Edition, August 1999 (2007). Global Standards
“Substructure” means a structure that surrounds the wellbore at the surface and provides the working area for certain employees. It may contain the rotary table.
[Mich. Admin. Code R 408 (2013)].
Source: Oil and Gas Drilling and Servicing Operations, Michigan Administrative Code R 408, February 8, 2013. Regulations
Refer to Drill Floor Substructure.
Source: API RP 64, Recommended Practice for Diverter Systems Equipment and Operations, Second Edition, November 2001 (March 1, 2007). Global Standards