Título: | GEOMECHANICAL EVALUATION OF RUBBLE-ZONES BELOW SALT ROCKS | ||||||||||||
Autor: |
THIAGO FREITAS LOPES CONCEICAO |
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Colaborador(es): |
EURIPEDES DO AMARAL VARGAS JUNIOR - Orientador |
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Catalogação: | 22/FEV/2019 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=37103&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=37103&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.37103 | ||||||||||||
Resumo: | |||||||||||||
The rise in the price of a barrel of oil in the 2000s and the increasing demand for this commodity, deepwater oil exploration became more attractive, favoring opportunities in subsalt and pre-salt plays in several areas of the world. As a consequence of this trend, the challenges of the oil industry have become ever greater. One of the challenges in drilling wells in evaporites is to minimize the creep to avoid the well collapse. In addition geological scenarios with the presence of salt structures can cause problems
of mechanical instability also during drilling of wells in the rocks adjacent to the salt. The main problems associated with this scenario are caused by the change in magnitude and the rotation of the principal stresses around these salt structures, mainly at the interfaces between the salt and the adjacent rocks, colloquially called rubble zones. The present work proposes a geomechanical evaluation of the state of stresses in subsal region where the mechanical instability was verified during the drilling of a well. This
evaluation was made from numerical simulations of the plane deformation state of a 2D geological section of the area, where a viscoplastic behavior was imposed for the evaporites; and elastoplastic with Cam-Clay and Mohr- Coulomb plasticity criteria for the region below the salt. As a result, we will discuss the voltage trajectories obtained in the simulation with the two types of elastoplastic materials, evidencing a methodological approach to subsidize the prediction of the well stability window in regions with allochthonous salt structures, since the stresses in situ in these regions are significantly altered and it is impossible to accurately predict the magnitude of these voltages from conventional analytical models. Better prediction of in-situ stresses translates into better forecasting of the operating window, thereby
reducing operational risks and improving the safety and cost-effectiveness of well designs.
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