Numerical modeling of deformation in carbonates and implications for the formation of karst

The effect of the presence of fractures on fluid flow in reservoir is nowadays a fundamental theme of interest to the oil industry. In the case of carbonate rocks, the study of the contribution of fractures on reservoir efficiency becomes more complex due to the reactive nature of these rocks to...

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Main Authors: Juliana Gomes Rabelo, Aline Theophilo Silva, Francisco Hilário Rego Bezerra, Anderson Moraes
Format: Article
Language:English
Published: Universidade de São Paulo 2015-06-01
Series:Geologia USP. Série Científica
Subjects:
Online Access:http://ppegeo.igc.usp.br/pdf/guspsc/v15n2/a05v15n2.pdf
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author Juliana Gomes Rabelo
Aline Theophilo Silva
Francisco Hilário Rego Bezerra
Anderson Moraes
author_facet Juliana Gomes Rabelo
Aline Theophilo Silva
Francisco Hilário Rego Bezerra
Anderson Moraes
author_sort Juliana Gomes Rabelo
collection DOAJ
description The effect of the presence of fractures on fluid flow in reservoir is nowadays a fundamental theme of interest to the oil industry. In the case of carbonate rocks, the study of the contribution of fractures on reservoir efficiency becomes more complex due to the reactive nature of these rocks to circulating fluid and the high tendency to form karst. The fractures act as agents that focus fluid percolation and exert structural control on the formation of karst. For the oil industry, this scenario can be favorable became of the increasing of porosity and permeability of secondary fractures, but also poses risks to the operation. This article investigates, under the geomechanical point of view, how the presence of fractures influence the development of karst observed in carbonate rocks. The Jandaíra Formation was selected as an analogue geomaterial to fractured carbonate reservoirs in marginal basins of Brazil. The methodology adopted for this study included: (i) the use of satellite images, an UAV; (ii) Numeral modeling of the effect of the current tensions on the flagstone structures. Comparing the results of numerical modeling to the mapping performed on the images, it was found that the regions of the numerical models where the highest values of dilatancy occur coincided with local areas in the field (fault terminations and cross fractures), which represent the concentration of dissolution and karst formation. This work has established that there is a possible relationship between the stress concentration and the dissolution along the structural fabric observed in fractured field flagstones and showed that the dilatancy process is probably responsible for the occurrence of preferential dissolution by fractures in carbonate rocks.
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spelling doaj.art-e1a19a61c31b45b7bd7e392dc78abcf42022-12-22T00:15:43ZengUniversidade de São PauloGeologia USP. Série Científica1519-874X2316-90952015-06-011529911010.11606/issn.2316-9095.v15i2p99-110Numerical modeling of deformation in carbonates and implications for the formation of karstJuliana Gomes Rabelo0Aline Theophilo Silva1Francisco Hilário Rego Bezerra2Anderson Moraes3Programa de Pesquisa e Pós-graduação em Geodinâmica e Geofísica, Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte - UFRN, Campus Universitário, CEP 59072-970, Natal, RN, BR Petrobras/CENPES, Rio de Janeiro, RJ, BRDepartamento de Geologia, Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte - UFRN, Natal, RN, BRPetrobras/CENPES, Rio de Janeiro, RJ, BRThe effect of the presence of fractures on fluid flow in reservoir is nowadays a fundamental theme of interest to the oil industry. In the case of carbonate rocks, the study of the contribution of fractures on reservoir efficiency becomes more complex due to the reactive nature of these rocks to circulating fluid and the high tendency to form karst. The fractures act as agents that focus fluid percolation and exert structural control on the formation of karst. For the oil industry, this scenario can be favorable became of the increasing of porosity and permeability of secondary fractures, but also poses risks to the operation. This article investigates, under the geomechanical point of view, how the presence of fractures influence the development of karst observed in carbonate rocks. The Jandaíra Formation was selected as an analogue geomaterial to fractured carbonate reservoirs in marginal basins of Brazil. The methodology adopted for this study included: (i) the use of satellite images, an UAV; (ii) Numeral modeling of the effect of the current tensions on the flagstone structures. Comparing the results of numerical modeling to the mapping performed on the images, it was found that the regions of the numerical models where the highest values of dilatancy occur coincided with local areas in the field (fault terminations and cross fractures), which represent the concentration of dissolution and karst formation. This work has established that there is a possible relationship between the stress concentration and the dissolution along the structural fabric observed in fractured field flagstones and showed that the dilatancy process is probably responsible for the occurrence of preferential dissolution by fractures in carbonate rocks.http://ppegeo.igc.usp.br/pdf/guspsc/v15n2/a05v15n2.pdfFracturesKarstNumerical modelingJandaíra Formation
spellingShingle Juliana Gomes Rabelo
Aline Theophilo Silva
Francisco Hilário Rego Bezerra
Anderson Moraes
Numerical modeling of deformation in carbonates and implications for the formation of karst
Geologia USP. Série Científica
Fractures
Karst
Numerical modeling
Jandaíra Formation
title Numerical modeling of deformation in carbonates and implications for the formation of karst
title_full Numerical modeling of deformation in carbonates and implications for the formation of karst
title_fullStr Numerical modeling of deformation in carbonates and implications for the formation of karst
title_full_unstemmed Numerical modeling of deformation in carbonates and implications for the formation of karst
title_short Numerical modeling of deformation in carbonates and implications for the formation of karst
title_sort numerical modeling of deformation in carbonates and implications for the formation of karst
topic Fractures
Karst
Numerical modeling
Jandaíra Formation
url http://ppegeo.igc.usp.br/pdf/guspsc/v15n2/a05v15n2.pdf
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AT franciscohilarioregobezerra numericalmodelingofdeformationincarbonatesandimplicationsfortheformationofkarst
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