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Industry Glossary Term

Tunnel Portal

The open entrance and exit points of a tunnel where underground meets surface operations. For subcontractors, portals are critical mobilisation zones for equipment, crews, and material staging. Access, congestion, and safety controls at portals directly affect your crew's productivity and schedule.

Related Terms

FID (Final Investment Decision)

Industry

The point when a project owner formally approves funding and commits to proceeding with a major project. For subcontractors, FID is the trigger that converts preliminary work into confirmed scopes and purchase orders. Mobilisation planning, crew hiring, and equipment sourcing typically begin after FID is announced.

Reamer

Industry

A downhole tool that enlarges or stabilises a borehole during drilling operations. Subcontractors supplying or operating reamers must ensure proper tool specifications match formation conditions. Rental and mobilisation costs are typically scoped into the drilling services contract.

Shut-In Production

Industry

A well or facility that has been temporarily halted from producing oil or gas. For subcontractors, shut-ins often mean suspended work orders and delayed invoicing. Confirm contract terms around standby rates before production stops.

Frac Flowback

Industry

The phase after hydraulic fracturing when water, sand, and hydrocarbons flow back to surface from the wellbore. Subcontractors are often mobilised quickly to manage fluid handling, testing, and disposal. Flowback work can be short-duration but requires crews and equipment on standby.

Well Spacing

Industry

The regulated distance between wellbores on a pad or lease area. Tighter spacing means more wells drilled closer together, increasing crew density and equipment demand. Subcontractors should anticipate compressed timelines and overlapping scopes when spacing is tight.

Custody Transfer

Industry

The formal handover point where ownership or responsibility for a measured quantity of oil, gas, or other product moves from one party to another — typically triggering billing, invoicing, or contractual obligations for subcontractors involved in metering, transport, or handling operations. Field service crews working custody transfer points must ensure measurements are accurate and fully documented, as discrepancies can directly affect client invoices and liability.

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