Foundation Performance of Offshore Jack-Up Drilling Rigs

An offshore fleet of about 435 mobile jack-up rigs is currently drilling oil and gas wells around the world. About 2.6% of these jack-up rigs annually experience an accident which is far greater than any other type of offshore drilling unit. Over one-third of these accidents are associated with foundation problems. Certain geological conditions pose particular hazards to the foundation performance of mobile jack-up rigs. To reduce the risk of foundation failure, these hazards can and should be identified by investigating subsurface conditions. Considerable interest is being given to assessing the accuracy of the analytical methods now available to predict the foundation performance of jack-up drilling rigs. Some commonly used analytical methods are reviewed and actual case histories are presented.