Project review
Deepwater installs a retrofit cathodic protection system for a fixed platform in the South China Sea.

Overview

The Lufeng (LF) 13-2 WHP is a fixed-production platform owned and operated by the Chinese National Offshore Oil Company (CNOOC). The 4-leg structure is located in the South China Sea in approximately 430 ft. [132 m] of seawater and was installed in 2005. A galvanic cathodic protection (CP) system was installed at the time of construction and was designed to last 10 years. Less than 3 years into the service life of the platform, it was discovered that several contributing factors had resulted in a shortened system lifespan which was predicted to be closer to 5 years. Deepwater Corrosion Services, Inc. (DCSI) has been contracted to design, supply and supervise the installation of an Impressed Current Cathodic Protection (ICCP) retrofit system for the LF 13-2.

The supplied CP system consists of:

• 2 RetroBuoy impressed current anode sleds
• Double-armored power cables (1,000 feet long)
• 2 topside marine transformer-rectifiers rated at 500 Amps
• 36 RetroClamp HD Cable Grippers for subsea cable management
• 2 permanently installed dual reference electrodes (DR-III)
• Topside CP-monitoring panel

Installation

For the LF 13-2 retrofit, DCSI designed a fully ROV-installable remote ICCP system.  Modifications were made to the proprietary RetroClamp to create a ROV-installable, subsea cable-management systemthat fixes the ICCP power cables to an existing 14” (OD) J-tube EL (-) 20 000 m to EL (-) 132 000 m.

Systems design and supply was completed in less than 6 months. The offshore installation will be carried out by the Chinese Offshore Oil Engineering Company (COOEC) in conjunction with CNOOC and is scheduled for spring 2010.

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