SITE WORK AND SCHEDULED INSPECTIONS
Recent Experience Case Study

Allen gearbox inspection - off-shore India
ONGC Offshore Platforms, India

Project background

The Oil & Natural Gas Corporation Ltd (ONGC) operates a number of platforms offshore India. On the NQO, SHQ and BPA platforms, TB5000 generator sets are in operation providing critical power for the platform, including the power for the compressor sets which are electric motor driven.

The challenge

Allen Gears were required to carry out 10 overhauls of TB5000 units on these platforms as follows:

• NQO Platforms x 4 units
• SHQ Platforms x 3 units
• BPA Platforms x 3 units.

All the platforms run the turbines full time with one turbine kept as emergency back up (ie NQO Platform run three generator sets full time, with 1 kept as emergency standby unit in case of failure on one of the other three)

Each is fitted with an Allen Gears epicyclic speed reducing unit. These were installed in 1984 and have not had gearbox overhauls for many years.

6 days per unit was allowed for each overhaul.

The outcome

Allen Gears service engineers had a very limited timescale to undertake the work due to the pumping and compression capabilities of the rigs. The generator sets had to be overhauled within 6 working days per gearbox to avoid the delays and loss of revenue created by the compressor sets having no power.

ONGC insisted that Allen Gears undertake this work, as the OEM, because of our experience within field service and because we can provide full technical support to our engineers on site should the need arise.

The success of the above contract, and the outstanding ability of our field service engineers, has convinced ONGC to use Allen Gears to overhaul 8 epicyclic gearboxes at their onshore refinery at Assam

Technical Data