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Industry Glossary Term

Differing Site Conditions

Unexpected ground, soil, or subsurface conditions that differ materially from what the contract documents described. Subcontractors can use this clause to claim additional compensation or time when surprises drive up costs. Always document and notify the general contractor or owner immediately upon discovery.

Related Terms

AFE (Authorization for Expenditure)

Industry

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.

Condensate

Industry

A light liquid hydrocarbon that separates from natural gas during production and processing. Subcontractors handling condensate must follow strict hazmat protocols, as it is highly volatile and flammable. It is often measured and valued separately from crude oil on production sites.

Topside Fabrication

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.

Pipeline Tie-in

Industry

A pipeline tie-in is the physical connection of a new pipeline section to an existing live system. For subcontractors, tie-in work often requires hot-tap certified crews and strict isolation procedures. Scheduling is critical, as tie-ins typically involve planned shutdowns with tight production windows.

BHA (Bottom Hole Assembly)

Industry

The collection of drilling tools and equipment at the bottom of the drill string, including the drill bit, drill collars, stabilizers, and downhole motors. For drilling subcontractors, BHA configuration directly impacts drilling performance, tool wear rates, and operational efficiency.

BOE (Barrel of Oil Equivalent)

Industry

A standardised unit of energy measurement that converts different types of oil and gas production into equivalent barrels of crude oil, used by operators to report total production volumes when determining project scope and service requirements for subcontractors.

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