The Maleo Producer is a converted Bethlehem JU250 mat-supported jack-up unit, which was installed m July 2006, on a soft, normally consolidated clay foundation some 40 km (25 mi) south east of Madura Island and approximately 25 km (16 mi) south of Puteran Island, offshore Indonesia. The unit was connected to a wellhead platform, and gas production began in late 2006. An initial site investigation performed in 2003 indicated that the undisturbed soil conditions consisted of a soft normally consolidated clay profile, with an undrained shear strength of 2 kPa (40 psf) at the mudline, linearly increasing with depth at a rate of 1.22 kPa/m (7.83 psf/ft) down to a depth of around 14 m (46 ft), below which a slightly stronger clay was encountered. The issue of on-bottom stability of the unit and its resistance to overturning were questioned by the classification society (ABS) as part of the reclassification of the rig. The behavior of the foundation under extreme storm loads and seismic events could be more reliably predicted by the designer, and more readily accepted by ABS, if new soil data were available. Two types of soil data were required 1) soil data for foundation design and re-analysis under and around the mat and 2) soil data for seismic analysis of the installation. This paper describes the extensive site characterization undertaken to prove the stability of the Maleo Producer facility during both the design storm and seismic events.
展开▼
