API Spec 17D-2021 (2025) PDF

Full title and description

API SPEC 17D:2021 — Specification for Subsea Wellhead and Tree Equipment (Third Edition). This edition includes Errata 1 (2021), Addendum 1 (2022) and Addendum 2 (2025); it provides technical requirements and accepted practices for the design, manufacture, testing, handling and installation of subsea wellheads, mudline wellheads, drill‑through mudline wellheads and both vertical and horizontal subsea trees, plus associated tooling and subassemblies.

Abstract

This specification sets minimum requirements and product specification levels for subsea wellhead and tree equipment used in offshore hydrocarbon production. It covers components (tubing hangers, tree connectors, valves, actuators, chokes, seals, guide frames, caps, fittings), material and welding requirements, quality assurance and factory acceptance testing (FAT), marking, storage and shipping, and the tooling required to handle, test and install assemblies. The document as currently published also contains addenda through 2025 that update clarifications, errata and limited technical amendments.

General information

• Status: Current (base 2021 edition with Addendum 2 published 2025).
• Publication date: Third edition published 2021 (commonly listed as 30 September / 1 October 2021); latest amendment Addendum 2 issued in 2025.
• Publisher: American Petroleum Institute (API).
• ICS / categories: 75.180.10 (exploration, drilling and extraction equipment; subsea wellhead/tree equipment).
• Edition / version: 3rd edition (2021) with Errata 1 (2021), Addendum 1 (2022) and Addendum 2 (2025).
• Number of pages: Typically listed in distributor records at ~250–270 pages depending on format and included adjuncts (page counts vary by publisher/combined addenda).

Key bibliographic facts and lifecycle notes are reported by API document listings and standards distributors; the 2025 addendum is recorded as the most recent amendment.

Scope

The standard applies to the full life‑cycle of subsea wellhead and tree equipment: functional and mechanical design requirements; structural and pressure‑containing components; materials and welding specifications; dimensional and interchangeability considerations; product specification levels (PSLs); inspection, testing and FAT requirements; marking, storage and transport; and the tooling and running equipment needed to install, test and recover subsea assemblies. It is intended for use by manufacturers, purchasers and operators of subsea completion systems, and is not a substitute for regulatory or jurisdictional requirements applicable at installation.

Key topics and requirements

• Definitions and equipment scope: subsea trees (vertical and horizontal), tree connectors, tubing hangers, tubing heads, mudline wellheads and drill‑through systems.
• Product Specification Levels (PSLs) and performance targets for components and assemblies.
• Material selection, corrosion and sour‑service considerations, and NDE requirements for critical parts.
• Welding qualifications, joint acceptance criteria and heat‑treatment requirements.
• Design and mechanical requirements for valves, chokes, actuators, seals and re‑entry interfaces.
• Factory acceptance testing (FAT), pressure testing, functional verification and inspection protocols.
• Handling, lifting and running tool requirements; installation and retrieval tooling interfaces.
• Marking, packaging, storage and shipment controls to preserve integrity prior to installation.

These topics form the technical backbone for subsea wellhead and tree procurement, manufacture and quality assurance.

Typical use and users

Used by oil & gas operators, subsea equipment manufacturers, design and engineering contractors, procurement and QA/QC teams, inspection bodies and test houses, and regulatory/compliance personnel involved with offshore well completions. The standard is referenced in technical specifications, purchase orders, engineering data packages and acceptance testing for deepwater and shallow‑water subsea projects.

Related standards

Commonly cross‑referenced standards include ISO 13628‑4 (Design and operation of subsea production systems — Part 4: Subsea wellhead and tree equipment) and standards for surface wellhead and tree equipment such as API 6A / ISO 10423; other API 17 series technical reports and recommended practices addressing subsea systems and verification also relate to API SPEC 17D. These documents are used together to establish functional interchangeability, test regimes and industry best practice.

Keywords

subsea, wellhead, subsea tree, mudline wellhead, drill‑through mudline, tubing hanger, tree connector, factory acceptance testing, PSA/PSL, material specification, welding, actuator, choke, API 17D, addendum 2025, deepwater, offshore completions.

FAQ

Q: What is this standard?

A: API SPEC 17D:2021 is the API specification for subsea wellhead and tree equipment (third edition) that defines design, material, testing and handling requirements for subsea wellhead and Christmas‑tree assemblies and associated tooling.

Q: What does it cover?

A: It covers scope/definitions, product specification levels, design and mechanical requirements, materials and welding, non‑destructive examination, factory acceptance testing, handling and installation tooling, marking, packaging and shipping, plus specific component requirements (valves, connectors, hangers, chokes, seals).

Q: Who typically uses it?

A: Manufacturers of subsea wellhead/tree equipment, oil & gas operators and their engineering/inspection teams, procurement specialists writing purchase specifications, and test/inspection houses performing FAT and acceptance activities.

Q: Is it current or superseded?

A: The base 2021 edition remains the controlling API SPEC 17D document but has been issued with Errata and Addenda; Addendum 2 was published in 2025 and is recorded as the most recent amendment, so users should apply the 2021 edition together with the 2021 errata and the 2022 and 2025 addenda where applicable. Check purchaser requirements for mandatory revisions.

Q: Is it part of a series?

A: Yes — API SPEC 17D is part of API’s subsea/specification family and is commonly used alongside other API and ISO standards covering wellhead and tree equipment (for example API 6A / ISO 10423 for wellhead/Christmas tree components and ISO 13628 series for subsea production systems).

Q: What are the key keywords?

A: subsea, wellhead, subsea tree, mudline wellhead, tubing hanger, tree connector, FAT, PSL, API 17D, addendum 2025.