OSHA

A budgeting document used in oil and gas projects that outlines expected costs and seeks approval before work begins. Subcontractors often work under AFEs issued by operators.

The number of drilling rigs actively operating in a region. Published weekly by Baker Hughes, the rig count is a leading indicator of activity levels in the oil and gas industry.

The construction and assembly of the above-water structures on offshore platforms, including decks, modules, and processing equipment, where subcontractors are typically engaged for specialised trades such as structural welding, pipefitting, electrical, and instrumentation work. For field service companies, topside scopes often involve strict offshore safety certifications, remote logistics, and milestone-based billing tied to fabrication progress.

A type of subsurface rock layer—primarily limestone or dolomite—that subcontractors may encounter during drilling, completions, or civil excavation work, often requiring specialised equipment, bit selections, or modified drilling programmes due to its hardness and tendency to cause lost circulation events.

The initial release of fluids, sand, and gases from a wellbore after hydraulic fracturing, which requires specialised crews and equipment on-site to manage, separate, and dispose of the returned materials safely. For field service subcontractors, flowback operations represent a distinct scope of work with dedicated mobilisation requirements and often involve tight scheduling windows tied to the operator's completion timeline.

The maximum depth reached by a drilling rig during well construction, measured from the surface to the bottom of the wellbore. For subcontractors, TD determines project scope, equipment requirements, and billing milestones as it marks the completion of the drilling phase.