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Assessing the implications of tectonic compaction on pore pressure using a coupled geomechanical approach

Lookup NU author(s): Joshua Obradors Prats, Professor Mohamed Rouainia, Professor Andrew Aplin

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


Abstract

Overpressure prediction in tectonic environments is a challenging topic. The available pore pressure prediction methods are designed to work in environments where compaction is mostly one dimensional and driven by the vertical effective stress applied by the overburden. Furthermore, the impact of tectonic deformation on stresses, porosity and overpressure is still poorly understood. We use a novel methodology to capture the true compaction phenomena occurring in an evolving 3D stress regime by integrating a fully-coupled geomechanical approach with a critical state constitutive model. To this end, numerical models consisting of 2D plane strain clay columns are developed to account for compaction and overpressure generation during sedimentation and tectonic activity. We demonstrate that a high deviatoric stress is generated in compressional tectonic basins, resulting in a substantial decrease in porosity with continuing overpressure increase. The overpressure predictions from our numerical models are then compared to those estimated by the equivalent depth method (EDM) in order to quantify the error induced when using classical approaches, based on vertical effective stress, in tectonic environments. The stress paths presented here reveal that a deviation from the uniaxial burial trend can substantially reduce the accuracy of the EDM overpressure predictions.


Publication metadata

Author(s): Obradors-Prats J, Rouainia M, Aplin AC, Crook AJL

Publication type: Article

Publication status: Published

Journal: Marine and Petroleum Geology

Year: 2017

Volume: 79

Pages: 31-43

Print publication date: 01/01/2017

Online publication date: 27/10/2016

Acceptance date: 19/10/2016

Date deposited: 09/11/2016

ISSN (print): 0264-8172

ISSN (electronic): 1873-4073

Publisher: Elsevier

URL: http://dx.doi.org/10.1016/j.marpetgeo.2016.10.017

DOI: 10.1016/j.marpetgeo.2016.10.017


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