Alloy Steel Drilling Rig Parts Swivel API 8C For Hoisting & Circulation Equipment

Swivel – API 8C Hoisting & Circulation Equipment for Drilling Rigs

Product Overview

A swivel is a critical piece of hoisting and circulating equipment on a drilling rig or workover rig. It hangs directly beneath the travelling block and above the kelly drive (or top drive), serving as the vital link between the stationary rotary hose and the rotating drill string-. The swivel performs three essential functions simultaneously: it supports the full weight of the drill string, allows the drill stem to rotate freely, and provides a high-pressure seal that enables drilling fluid to be circulated downhole.

The equipment is mainly used in conjunction with a series of drilling rigs and workover rigs. Our swivels are designed and manufactured in compliance with API Spec 8C (Drilling and Production Hoisting Equipment) and are available with API monogram certification. We offer conventional swivels, spinner swivels, and power swivels to suit different operational requirements.

How a Swivel Works

The swivel consists of two main assemblies: a stationary assembly (the body, bail, and gooseneck) and a rotating assembly (the swivel stem and shaft). The bail connects the swivel to the travelling block, while the gooseneck provides the entry point for the mud hose.

Drilling mud flows from the stationary rotary hose through the gooseneck, down through the swivel body, and into the hollow swivel stem. From there, it passes into the kelly and then down the drill string to the bit. The swivel stem rotates with the drill string while the body remains stationary, with a sealing system (packing and washpipe) preventing high-pressure mud from leaking. According to API Spec 8C, the angle between the gooseneck centreline and the vertical shall be 15 degrees.

Types of Swivels

Conventional Swivel: The standard swivel design, suitable for most drilling and workover applications where the rotary table provides the rotational power to the drill string. The swivel simply suspends the string and allows it to rotate freely while providing a mud circulation path.

Spinner Swivel: A combination of a conventional swivel and a kelly spinner, driven by an air motor or hydraulic motor-. The spinner assists in making and breaking connections by rotating the kelly (and thus the drill string) independently of the rotary table, significantly reducing the time and effort required for tripping operations. A keyless connection is adopted between the spinner and the central pipe of the swivel.

Power Swivel: A self-contained, motorized swivel that provides its own rotational force to the drill string-. Power swivels eliminate the need for a rotary table and kelly, making them ideal for top-drive drilling systems, horizontal directional drilling (HDD), and coiled tubing operations. They can be installed in a standard derrick or mast and provide smooth, shock-free torque that reduces damage to the drill string.

Technical Specifications

Conventional & Spinner Swivels

Source: Manufacturer specifications

Power Swivels

Source: Manufacturer specifications

Key Features

API 8C compliant – Designed, manufactured, and tested to API Spec 8C, with PSL1 certification available

High-strength alloy steel construction – Main load-carrying components are forged or cast from high-strength alloy steel and subjected to nondestructive testing

Reliable sealing system – Features a cartridge-type packing assembly that allows rapid replacement of washpipe and packing on the rig floor without disconnecting the mud hose or gooseneck

Optional low-temperature capability – Available for arctic and cold-climate operations

Interchangeable connections – Thread connections comply with API Std 5B

Applications

Conventional drilling rigs – Suspending drill string and circulating mud in rotary drilling operations

Workover rigs – Well intervention and maintenance operations

Medium to deep wells (1,000–6,000 m) – Suitable for most drilling depths

Top-drive drilling systems – Power swivels for motorized rotation

Horizontal Directional Drilling (HDD) – Power swivels for pipeline installation

Coiled tubing operations – Power swivels for specialized applications

Fishing and snubbing operations – Where frequent connection changes are required

The swivel is an indispensable component of any drilling or workover rig, combining hoisting, rotation, and mud circulation into a single, reliable unit. Our swivels are API 8C certified, available in conventional, spinner, and power configurations, and built from high-strength alloy steel for maximum durability in demanding oilfield conditions.

Contact us to discuss the right swivel for your drilling or workover project.