China has brought on stream another oil field in the South China Sea, using a floating production, storage, and offloading (FPSO) unit.
JHN Oil Operating Co., a joint venture of Japan Hunan Oil Corp. and China National Offshore Oil Corp. unit Nanhai East Oil Corp. (NEOC), started up Lufeng 13-1 oil field last month.;
The field holds proved reserves of 32.5 million bbl out of original oil in place of 140 million bbl.
Production started at about 4,500 b/d and is expected to ramp to more than 20,000 b/d in 1995. Field life is projected at 8 years. A proved in 1990, Lufeng 13-1 development cost $300 million. NEOC" contributed $75 million of that cost .
FPSO INSTALLATION
JHN in early August began installing an FPSO in 465 ft of water Lufeng 13-1 field in the South China Sea about 150 miles off Hong Kong.
Nanhai Shengkai FPSO is equipped with a disconnectable turret mooring system designed and installed by Sofec Inc., Houston, a unit of FMC Corp. The mooring system was fabricated in Japan and installed on the Nanhai Shengkai in Singapore. Nanhai Shengkai FPSO formerly was the 128,000 dwt Sea Queen tanker.
Following conversion, the FPSO sailed July 22 from Singapore. JHN general contractor Clough Stena (Asia) installed Nanhai Shengkai at Lufeng in a period of several weeks, during which the vessel's mooring system was disconnected and reconnected several times for commissioning and ship crew training. Clough Stena subcontracted a unit of Sonsub Inc., Houston, to help set, hook up, and tension anchors and run a flexible flowline over a midwater arch to a previously installed jacket
. The FPSO is moored with symmetric eight leg layout. The turret is attached by a collet connector to a buoyant anchor leg support structure, or spider buoy. In the Sofec design, the collet connector is in series with a hydraulic tensioner, which transfers connection forces through surfaces preloaded in compression at the outer diameter of the turret shaft. The FPSO's turret is mounted inboard near the FPSO's bow with the main roller bearing located on the top deck, far from direct exposure to seawater and easily available for inspection and maintenance.
Sofec's turret mooring design allows Nanhai Shengkai to disconnect quickly to avoid severe weather or for maintenance. The disconnect threshold is equal to a 100 year nontyphoon storm environment and the system in mid-August during installation weathered Typhoon Tasha without disconnecting.
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