Slide analysis and control of jack-up rig during repeat placement

Abstract:

With the continuous development of exploration and development in the Xihu area， the number of jack-up drilling platforms in the East China Sea is also increasing. Due to the influence of typhoon and multiple operations in the same location， the jack-up drilling platform will inevitably repeat the operation near their previous position， and cause the pile shoe slide phenomenon； thus leading to the decrease of cantilever operation range when in place， and failure to meet the needs of drilling operation. In the worse case， it may even affect the structural safety of the platform， resulting in engineering accidents with high operation risk. Taking the pile shoe of H9 jack-up drilling platform as an example， this paper analyzes the mechanical characteristics of the pile shoe under partial coincidence conditions， studies the failure mode of seabed soil， and puts forward horizontal force calculation models of the pile shoe in different types of soil. The finite differential method of the slide line is used to calculate the ultimate bearing capacity of the pile shoe. This paper analyzes the measures taken during H9 platform repeat placement， with a series of safety control measures put forward according to the requirements of offshore operation， which can provide a reference for safe and efficient jack-up rig repeat placement.

Key words:jack-up rig;repeat placement;sliding of pile shoe;ultimate bearing capacity;control measures