Flowhead / Surface Test Tree

PRODUCT OVERVIEW

Purpose and operating principle

A flowhead, also called a surface test tree, is a pressure-control assembly installed at the top of a test string. Its principal duty is to control flow into and out of the well while providing flow- and kill-line access, a swab access point and a safe handling interface.

How the arrangement works

The typical arrangement uses a master valve, swab valve and two wing valves. One wing can be hydraulically actuated for remote closure. A lifting sub and quick-union connection provide an upper handling and pressure-access interface, while an optional swivel below the main body allows the string to rotate without rotating the connected surface lines. The master valve may be integral to the main block or positioned below it.

Technical features

• Solid-block surface control head for well testing, perforating and wireline duties
• Master valve, swab valve, flow-wing valve and kill-wing valve arrangement
• Integral-master-valve or below-block master-valve configurations
• Manual, pneumatic, hydraulic, fail-safe or electric actuation options according to the approved design
• Optional oil- or grease-filled swivel below the central body
• Top handling sub compatible with the selected elevator arrangement
• ACME-threaded or flanged main-bore connection options
• Downward-angled flow and kill outlets available where rig-up space is restricted
• Removable crash frame available to protect valves and actuators
• Metal-to-metal sealing and hard-faced slab-gate trim available for severe service

Typical applications

• Onshore and offshore well testing
• Drill-stem testing and reservoir clean-up
• Wireline and perforating operations
• Slickline and coiled-tubing intervention
• Well stimulation
• Completion and subsea installation support, subject to the approved programme