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Product category: Oil, Gas, Petrochemical Industry News
News Release from: Inertial Aerosystems UK | Subject: Tiltmeters
Edited by the Processingtalk Editorial Team on 29 March 2006

Riser Flex Joint limits offshore rig
downtime

Tiltmeters measure the angle of the riser flex joint and the top of the Blow Out Preventer on offshore drilling rigs: this is often difficult to monitor, and can result in wear holes in the riser

Excessive tilt angles between the lower riser flex joint and the top of the Blow Out Preventer (BOP) are difficult to monitor and can lead to friction between the lower riser and the drill pipe, often wearing a hole in the riser The resulting downtime can have a daily cost exceeding US$200,000, and much higher if repairs cannot be carried out due to adverse weather or sea conditions and/or unavailability of spare parts

Inertial Aerosystems have introduced a new system which automatically monitors, displays and logs the tilt angle of the lower riser above and below the pivot.

This new capability improves the ability to maintain the flex joint angle within the required tolerances.

With continued awareness of the flex joint tilt angle, drilling operations can potentially be extended by avoiding conditions of excessive tilt.

In addition it will not be necessary to curtail operations at times when high currents or wave heights prevent deployment of an ROV used for reading the existing "bulls eye" monitor.

The flex joint connects the lower riser to the top of the BOP.

Tiltmeters will measure the angle of the flex joint in two locations.

One location is below the pivot where the absolute angle between the riser and the BOP is to be kept within 1 degree of vertical.

The other is above the pivot, where measurements will be used to keep the differential tilt between the upper and lower parts of the flex joint within 0.5 of a degree.

Power and RS485 signals are carried between the tiltmeters and rig floor by one 12-conductor cable.

A "Y" cable assembly will connect this cable to the two tiltmeters, each of which needs 6 conductors.

The main cable is strapped to the riser and deployed from an air-powered spooler (air winch) on the rig floor.

A separate cable connects the main cable to the monitoring system.

This innovative system will transmit biaxial measurements from the deepwater tiltmeters once per second.

The measurements are displayed on an easy to read LCD monitor.

It will depict a "bull's eye" and the associated tilt measurements.

These are logged at intervals of 5 seconds, whilst the log file is analysed every 5 minutes; calculating maximum, minimum and the average.

These values can then be collected and transmitted to any surveillance site. Request a free brochure from Inertial Aerosystems UK ...

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