The Role of The Model of Mechanical Properties of Bottom Sediments in The Problems of Stability of Jack-up Drilling Rigs Under Seismic Impacts

Abstract

Summary When developing such fields and drilling wells, jack-up floating drilling rigs (jack-up rigs) are actively used, the main approaches to the design and use of which were formulated relatively long ago. The operation of jack-up drilling rigs is associated with the solution of many tasks that do not arise during the development of fields located on the continent. The main focus of this work is mechanical processes that lead to a violation of stability. Among the risks, one can single out the loss of stability of the jack-up rig support columns, as well as the development of mechanical damage in them. In this work, the problem of jack-up rig stability under seismic impacts was solved using the finite element method. A finite element model was created containing elements of a tetrahedral shape. The key components of the model were: a hull, three support columns, and a sediment section. Based on the results of numerical modeling, the spatial distributions of stress and strain fields in the jack-up rig itself and in the vicinity of the supporting columns were determined. The equilibrium stress-strain state of the medium due to the jack-up rig’s own weight and soil resistance, as well as its disturbance caused by the arrival of a surface seismic wave from a large earthquake, was considered. In the course of the work, the dependence of the jack-up rig stability under various factors was investigated. The results obtained in the course of the work demonstrate the possibilities of mathematical modeling for predicting risks during the operation of the jack-up rig during the development of fields located on the continental shelf.