No abstract

No abstract

No abstract

The Baldpate compliant tower, in Garden Banks block 260 in the Gulf of Mexico, is the first free standing, non-guyed compliant tower. Situated in 1,648 ft of water, it measures 1,900 ft. from the flare tip to the sea floor. The tower is a 19-slot drilling/production platform set over a 9-slot drilling template, has production facilities for 60,000 BOPD and 200 MMSCFD, and supports two steel catenary export risers. The tower was installed in the spring of 1998. The tower has four basic structural components; the foundation piles, jacket base section (JBS), jacket tower section (JTS) and deck. Load-out weights for these were approximately 5,000 s. tons, 9,000 s. tons, 20,000 s. tons, and 4,000 s. tons respectively. This paper focuses on the installation of these components and also on the installation of the drilling template (Installed in 1994) and the docking and leveling piles (installed in 1996). Unusual aspects of the installation included the use of leveling piles instead of mud mats, deep lowering operation for the massive jacket base section; handling 530-feet long single-piece foundation piles and driving them with a single underwater hammer; launching of the jacket tower section from a launch barge that it exceeded in length by some 750 feet; and vertical mating of the two sections of the jacket at a depth of 1,300 feet. Introduction The Amerada Hess Baldpate compliant tower is located in the Gulf of Mexico in Garden Banks block 260 at a nominal water depth of 1648 feet. Particulars of the docking and leveling piles, the jacket base section, the skirt piles and the jacket tower section are; Docking Piles (2 no.) Dimensions : 84 inches O.D. × 206 feet Weight (dry) : 175 short tons (each) Leveling Piles (4 no.) Dimensions : 60 inches O.D. × 250 feet Weight (dry) : 125 s. tons (each) Jacket Base Section (JBS) Dimensions : 355 feet high, bottom 140 × 140 feet to leg centerlines, top 90 × 90 feet Weight (dry) : 9,000 s. tons Foundation Piles (12. no) Dimensions : 84 inches O.D., 531 feet Weight (dry) : 480 s. tons (each) Jacket Tower Section (JTS) Dimensions : 1410 feet high (including stabbing pins), bottom 90 × 90 feet, top 90 × 90 feet Weight (dry) : 20,000 s. tons The contract for the transportation and installation of the platform components was awarded in February 1996 to HeereMac. Installation of the docking and leveling piles was completed in September 1996. Installation of the other platform components was completed in June 1998.

In Part 1 shallow-shell equations expressed in elliptic co-ordinates have been solved in terms of Mathieu functions. Boundary conditions for the rigid insert and for the unreinforced hole are discussed in some detail. Results for an unreinforced opening are compared with experiment and satisfactory agreement is obtained. In Part 2 a parametric study has been made of the factors affecting the stresses at rigid inclusions and at unreinforced holes of elliptical shape in spherical shells. This work makes possible a simple method of representing the results in terms of the stress-concentration factors in flat plates, and a single geometrical variable. The results are verified by experiment. On the basis of this study predictions of the stresses at the intersection of non-radial nozzles in pressure vessels have been made. The theoretical results are compared with experimental evidence already available and reasonable agreement is found.