Appraisal Well

The horizontal section of a directionally drilled well, extending sideways through the target formation. Laterals can stretch several kilometres, requiring extended crew mobilisations and staged service scopes. Subcontractors should clarify lateral length upfront, as it directly affects equipment needs and job duration.

Natural gas cooled to -162°C to become liquid for easier transport and storage, creating specialized work opportunities for subcontractors in cryogenic equipment maintenance, pipeline construction, and terminal facilities that require specific safety certifications and cold-weather expertise.

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 set of advanced extraction techniques—such as steam injection, chemical flooding, or CO2 injection—used to pull additional crude from mature or low-yield reservoirs, which drives demand for specialised field service crews, equipment operators, and maintenance contractors on long-term site assignments.

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.

A timeline that outlines when specific tools, equipment, or crews are deployed downhole or on-site during an operation, dictating when a subcontractor's services are required and for how long. For field service companies, the run schedule directly determines mobilisation timing, crew rotations, and invoiceable hours on location.

What Is an AFE in Oil and Gas and How Does It Affect Subcontractor Payments?

An AFE (Authorization for Expenditure) controls every dollar spent on an oilfield project. Learn how it affects your billing, change orders, and cash flow as a subcontractor.