Xijiang 30-2 and 24-3 Caisson Guide Failure Analysis and Repair

摘要

On December 6, 1996, two seawater lift guides (one at the +19 foot level and one at the -40 foot level on the same caisson) and one firewater caisson guide (at -40 foot level) on the Xijiang 30-2 (XJ30-2) platform offshore South China Sea failed at the connection between the guide bucket and the standoff brace. The failed guides were missing and the standoff brace. The failed guides were missing and later retrieved from the seabed. Subsequent inspection detected cracks in other guides supporting the 24-inch caissons on both the XJ30-2 and Xijiang 24-3 (XJ24-3) platforms. Five temporary clamps (two firewater and two seawater on XJ30-2, and one firewater on XJ24-3) were installed to support the caissons at the -40 foot level to allow production to continue during the winter months. Analyses were undertaken to determine the cause of the failures and design of the final repair/strengthening to support the remaining caissons.