Open AccessStructural stability of the Weeks Island oil repository
Author(s) -
D.S. Preece,
Brian L. Ehgartner
Publication year - 1994
Language(s) - English
Resource type - Reports
DOI - 10.2172/48747
Subject(s) - pillar , subsidence , stability (learning theory) , oil storage , ground subsidence , geotechnical engineering , geology , fracture (geology) , mining engineering , petroleum engineering , structural engineering , engineering , computer science , paleontology , structural basin , machine learning
A 3-D finite element analysis was performed to evaluate the stability of the SPR upper and lower oil storage levels at Weeks Island. The mechanical analysis predicted stresses and strains from which pillar stability was inferred using a fracture criterion developed from previous testing of Weeks Island salt. This analysis simulated the sequential mining of the two levels and subsequent oil fill of the mine. The predicted subsidence rates compare well to those measured over the past few years. Predicted failure mechanisms agree with observations made at the time the mine was being modified for oil storage. The modeling technique employed here treats an infinite array of pillars and is a reasonable representation of the behavior at the center of the mine. This analysis predicts that the lower level pillars, at the center of the mine, have fractured and their stability at this time is questionable. Localized pillar fracturing is predicted and implies that the mine is entering a phase of continual time dependent deterioration. Continued and expanded monitoring of the facility and development of methods to assess and predict its behavior are more important now than ever