The last step in ballasting the Neptune spar involved spraying water into open hatches (Fig. 1).
A dynamically positioned vessel lifted the 4,000 ton topsides onto the hull (Fig. 2).Last September saw the installation of the world's first spar production facility in the Gulf of Mexico.
The Neptune structure is now moored in 1,930 ft of water in Viosca Knoll Block 826. Oryx Energy Co., operator of Neptune, expects production to start this month (OGJ, Sep. 23, 1996, pp. 35-36).
Fig. 1 shows the 700-ft, 11,000-ton steel hull on location. To upright the hull, two ballasting lines from J. Ray McDermott's dynamically positioned vessel, DB50, were connected to the spar. For the final stage of ballasting, fire monitor pumps sprayed water into open hatches on the structure. Upending the hull took about 8 hr of steady external ballasting at its lower end.
Deep Oil Technology developed the spar concept along with Spars International Inc., a joint venture between J. Ray McDermott Inc. and Aker Oil & Gas Technology a.s.
After the cylindrical hull was connected to a preinstalled six-point mooring system, DB50 lifted the 4,000-ton production topsides onto the hull (Fig. 2).
The facility is designed to handle 25,000 bo/d.
A second and larger spar is under construction for Chevron USA Production Co. That spar will be installed in 2,600 ft of water in Green Canyon Block 205. Unlike Oryx's Neptune, Chevron's Genesis spar will handle both drilling and production operations.
Chevron expects production from Genesis to start in 1998.
Copyright 1997 Oil & Gas Journal. All Rights Reserved.