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Title: Methods for Modeling and Analyzing Leached Caverns in Salt.

Abstract

Abstract not provided.

Authors:
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1148122
Report Number(s):
SAND2007-3249C
523031
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the ASME Applied Mechanics and Materials Conference held June 3-7, 2007 in Austin, TX.
Country of Publication:
United States
Language:
English

Citation Formats

Stone, Charles M. Methods for Modeling and Analyzing Leached Caverns in Salt.. United States: N. p., 2007. Web.
Stone, Charles M. Methods for Modeling and Analyzing Leached Caverns in Salt.. United States.
Stone, Charles M. Tue . "Methods for Modeling and Analyzing Leached Caverns in Salt.". United States. doi:. https://www.osti.gov/servlets/purl/1148122.
@article{osti_1148122,
title = {Methods for Modeling and Analyzing Leached Caverns in Salt.},
author = {Stone, Charles M.},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}

Conference:
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  • The use of material properties from triaxial creep tests in conjunction with finite element analyses provides a reasonably reliable method for predicting the volumetric response of salt caverns due to creep. The material testing procedures and the analytical approach used here have been shown to be valid by comparison of analytical results with flow rate and total volume data obtained in the field. These methods are being used to predict the response of new and existing caverns which will be employed in the Strategic Petroleum Reserve program.
  • This paper discusses (1) the acquisition of material properties, (2) the finite element program SANCHO, and (3) the comparision of analytical and field data for the caverns in the Bayou Choctaw Dome (Louisiana) and Eminence Dome (Mississippi). The use of material properties from triaxial creep tests in conjunction with finite element analyses provides a reasonably reliable method for predicting the volumetric response of salt caverns due to creep. The material testing procedures and the analytical approach used here have been shown to be valid by comparison of analytical results with flow rate and total volume data obtained in the field.more » These methods are being used to predict the response of new and existing caverns which will be employed in the Strategic Petroleum Reserve program.« less
  • An increasing interest is being shown worldwide in using leached salt caverns to store oil and natural gas. A critical factor in the use of existing caverns and the design of new ones is the creep behavior of the salt surrounding the caverns. An understanding of this behavior is being gained by using laboratory triaxial creep data as material property input to finite element computer programs designed to calculate displacements and stresses due to creep. An important step in verifying these predictive methods is the comparison of field data from existing caverns with finite element analyses which incorporate the materialmore » properties and geometry of each site. This comparison has been made for caverns in the Eminence Dome (Mississippi), West Hackberry Dome (Louisiana), and Bayou Chocktaw Dome (Louisiana) with reasonably good correlation being obtained between measured and predicted volumetric response of the caverns. These comparisons are discussed in this paper.« less
  • In 1975 Congress passed the Energy Conservation Act to establish a US Strategic Petroleum Reserve (SPR) with a capacity of 750 million barrels of crude oil. The most economic storage medium was determined to be salt caverns leached in salt domes in Louisiana and Texas. Salt caverns existed at several sites when the reserve was created. These were obtained by the US Department of Energy (DOE) and used to initiate SPR oil storage. In order to meet the storage capacity approved by Congress, new caverns also had to be leached. To support the resulting design effort, finite element computer programsmore » have been used to determine the creep closure and structural stability of salt caverns. Using site specific material properties including creep models, elastic moduli and fracture data, the finite element analyses have been replaced earlier empirical approaches to cavern design. This report presents results of such finite element analyses to determine the best cavern roof shape and the minimum pillar to diameter ratio, P/D. These numerical predictions indicate that the current cavern design is safe. 12 references, 7 figures, 2 tables.« less
  • In recent years, serious investigations of potential extension of the useful life of older caverns or of the use of abandoned caverns for waste disposal have been of interest to the technical community. All of the potential applications depend upon understanding the reamer in which older caverns and sealing systems can fail. Such an understanding will require a more detailed knowledge of the fracture of salt than has been necessary to date. Fortunately, the knowledge of the fracture and healing of salt has made significant advances in the last decade, and is in a position to yield meaningful insights tomore » older cavern behavior. In particular, micromechanical mechanisms of fracture and the concept of a fracture mechanism map have been essential guides, as has the utilization of continuum damage mechanics. The Multimechanism Deformation Coupled Fracture (MDCF) model, which is summarized extensively in this work was developed specifically to treat both the creep and fracture of salt, and was later extended to incorporate the fracture healing process known to occur in rock salt. Fracture in salt is based on the formation and evolution of microfractures, which may take the form of wing tip cracks, either in the body or the boundary of the grain. This type of crack deforms under shear to produce a strain, and furthermore, the opening of the wing cracks produce volume strain or dilatancy. In the presence of a confining pressure, microcrack formation may be suppressed, as is often the case for triaxial compression tests or natural underground stress situations. However, if the confining pressure is insufficient to suppress fracture, then the fractures will evolve with time to give the characteristic tertiary creep response. Two first order kinetics processes, closure of cracks and healing of cracks, control the healing process. Significantly, volume strain produced by microfractures may lead to changes in the permeability of the salt, which can become a major concern in cavern sealing and operation. The MDCF model is used in three simulations of field experiments in which indirect measures were obtained of the generation of damage. The results of the simulations help to verify the model and suggest that the model captures the correct fracture behavior of rock salt. The model is used in this work to estimate the generation and location of damage around a cylindrical storage cavern. The results are interesting because stress conditions around the cylindrical cavern do not lead to large amounts of damage. Moreover, the damage is such that general failure can not readily occur, nor does the extent of the damage suggest possible increased permeation when the surrounding salt is impermeable.« less