The paper describes EPMI's efforts to eliminate potentially catastrophic hydrocarbon liquid and gas discharge from the open drains of its platforms located offshore Peninsular Malaysia in the South China Sea.

The hydrocarbon discharges were largely precipitated by equipment failure and related events but were made physically possible by the use of a common discharge caisson by both the open and pressured drain systems.

For platforms containing major processing equipment, the modifications to separate the open drains from the pressured drains involve the installation of a second drain caisson. For other platforms, the systems were separated by returning the pressure drains discharge to the process stream. As a result of the described modifications, high pressure crude dumped to the drains even at very high flowrates cannot result in hydrocarbons to be discharged from the open drains.

All EPMI platforms have been modified and the installed systems are operating satisfactorily. EPMI now requires the complete separation of the pressured drains from the open drains in all its offshore installations.


Drain systems play a crucial role in the safe and environmentally acceptable operation of any offshore production facility. Efficient drain systems will allow produced fluids discharged from hydrocarbon process streams in a production facility to be safely disposed of. However, the failure of the drain system to perform as desired can result in safety and environmentally hazardous incidents.

Such failures of the drain system has resulted in incidents of hydrocarbon being discharged from the open drains on several EPMI platforms. These incidents were caused mainly by equipment failure and related operational events but were made possible by the physical use of a common drain caisson or the pressured process equipment drains and the open drains.

The modifications to the drain system of seventeen EPMI platforms are aimed at enhancing safety on the platform by providing a safe means of disposing produced fluids from the process stream. The retrofit work involves the physical separation of the pressured drains from the open drains. For the manned platforms, this was achieved with the use of a separate drain caisson for the open system. For the other unmanned platforms, discharges from the pressured drains are returned to the process stream.

Drain system modifications were successfully implemented on all the affected platforms. Installed systems are operating satisfactorily with no further incidents of hydrocarbon discharge from the open drains.

The US$3.1M spent for these modifications demonstrates EPMI'S commitment to provide safe and efficient facilities in all its operations.

EPMI has required the complete separation of the pressured and open drain systems with the use of dual caissons in all its offshore installations to ensure the elimination of hydrocarbon blowbacks and to allow the safe and efficient disposal of pressured produced fluids on its production facilities.


Location (Figure 1)

EPMI operates twenty-two platforms, 200 km offshore the east coast of Peninsular Malaysia in the South China Sea. Of these, twelve platforms are manned. The remaining ten, including a pump platform, are unmanned. These platforms are installed in water depths which vary between 60m to 75m.

Crude production is gathered at the Tapis Pump platform a nd sent onshore to the Terengganu Crude Oil Terminal (TCOT) where it is stabilized, and stored and subsequently exported to tankers through near-shore SALMS.

Manned Platform Operations (Figure 2)

The manned platforms are eight-legged structures with typically 21 to 32 well slots. These platforms have integrated modularised drilling, production, flare, power generation and accommodation facilities.

Other facilities may include gas compression, produced water handling equipment and water flood equipment.

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