The foundation performance of mat supported jack-up rigs, operated at more than 1300 locations in the Gulf of Mexico since 1957 are summarized. Rig operators were asked to provide a continuous chronological record of rig locations that were matched, where possible, with the water depth, bottom conditions (soil type and bottom slope), and environment (winds and waves). These data are incorporated into an analysis of the mat to predict the performance of the foundation for selected drilling locations. Particular attention is given to those rig locations that have experienced a severe hurricane. Mat supported jack-up rigs have experienced a total of 176 rig years of successful operations in a wide variety of environments. This experience has included water depths up to 259 feet, and bottom conditions encompassing very soft muds, sands and coral rock. Direct comparison of observed and predicted settlement of the mat in soft muds was difficult due to the inherent problems of defining the position of the mat relative to the seafloor. However, investigation of rig performance at ten sites in the paths of four severe hurricanes during 1957-1975 has revealed that although limited vertical and lateral movements have occurred in several instances on very weak soils, the serviceability of the rigs has been unaffected. No movements at all have been reported on clay soils whose strength exceeds 100 psf.

Media Info

  • Features: References;
  • Pagination: p. 821-830

Subject/Index Terms

Filing Info

  • Accession Number: 00138198
  • Record Type: Publication
  • Source Agency: Offshore Technology Conference
  • Report/Paper Numbers: V1, OTC 2503 Proceeding
  • Files: TRIS
  • Created Date: Aug 23 1976 12:00AM