LWD (Logging While Drilling)

The segment of the oil and gas industry involved in processing, storing, and transporting oil, gas, and NGLs. Includes pipelines, gathering systems, and processing plants.

A rock formation believed to contain oil or gas, targeted for drilling or evaluation. Subcontractors are often mobilised to support exploration work within these zones. Scope and duration of field service contracts may depend on how many prospective intervals a well will test.

The straight-line vertical distance from surface to a specific point in a wellbore, regardless of how the well is drilled — subcontractors working on directional or horizontal wells need to reference TVD (not measured depth) when scoping equipment reach, calculating hydrostatic pressures, or verifying work zone depths on service orders.

A contract between an operator and a service company that establishes the general terms and conditions for all future work. Individual jobs are then executed under work orders or AFEs referencing the MSA.

A contractor management platform used by operators to verify that subcontractors meet safety, insurance, and compliance requirements before being allowed to work on sites. Maintaining ISNetworld compliance is essential for subcontractors working with major operators.

The phase of oil and gas well development after drilling is finished, encompassing the work required to prepare a well for production — including perforating, fracturing, and installing wellhead equipment. For subcontractors, completions represent a concentrated burst of high-demand field work where specialised crews, equipment, and services are mobilised under tight timelines.

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.