Disk stack design valve trim solves Brent problem

Edited by the Engineeringtalk editorial team Nov 10, 2000

A protracted control valve problem on the Shell UK Brent Field offshore oil and gas production platforms has been overcome by the introduction of a high technology 'MLT' valve trim

A protracted control valve problem on the Shell UK Brent Field offshore oil and gas production platforms has been overcome by the introduction of a high technology 'MLT' valve trim, designed and manufactured by Severn Glocon.

The custom engineered 'Valve Retrofit Solution', used to eliminate the problem, was developed after the completion of a detailed failure analysis report produced by the Severn Group's aftermarket specialist company Severn Unival.

The detailed report was made possible by utilising the close technical partnership existing between the engineering support groups of Shell UK, Northern Integrated Services and Severn Unival.

Northern Integrated Services operate the engineering and maintenance support contract for the Shell UK Brent and Northern Field platforms.

Severn Unival have a proven technical expertise in the area of specialist valve repair and application engineering support.

Unival's expertise in this area is widely used by Shell and a large number of other major operating companies in the UK North Sea.

Persistent problems, related to the operation of the gas compressor recycling valves, were reported by the platform.

The problems were responsible for excessive down-time and maintenance costs.

Excessive noise, vibration and poor control, experienced during recycling and start-up operations, resulted in restricted operation and the premature failure of the valves.

Control valves removed from this application were regularly being returned to Severn Unival for repair.

Having completed a failure analysis investigation, Severn Unival proposed a high technology valve / trim alternative.

The 'MLT' trim solution offered is designed and manufactured by Severn Glocon specifically for severe and extreme valve applications.

The 'MLT' disk stack design valve trim presents a multi-stage pressure / multi-path labyrinth flow path to the fluid.

The computerised design enables the 'MLT' stack to be precisely sized to control energy dissipation and velocity.

Having successfully completed the initial performance trials the Severn Glocon 'MLT' valve trim solutions are now being introduced on all the relevant Brent Field production platforms.

The introduction of these modifications is in line with Shell / Northern Integrated Services identified goal for continuous improvement.

Commenting on the success of the 'MLT' valve for this application, Northern Integrated Services' Senior Instrument Engineer Peter Keay had the following comments: "Prior to changing to the MLT valve, the platforms were all subject to varying degrees of operational restrictions with their gas export compressors, due to excessive noise and vibration, the effects of which could be quite extreme.

Since fitting the MLTs on Brent the performance has been totally satisfactory and the marked difference has been noted by offshore Operations.".