Numerical Estimates of the Maximum Sustainable Pore Pressure in Anticline Formations using the Tensor Based Concept of Pore Pressure-Stress Coupling
The advanced tensor based concept of pore pressure-stress coupling is used to provide pre-injection analytical estimates of the maximum sustainable pore pressure change, ΔPc, for fluid injection scenarios into generic anticline geometries. The heterogeneous stress distribution for different prevailing stress regimes in combination with the Young's modulus (E) contrast between the injection layer and the cap rock and the interbedding friction coefficient, μ, may result in large spatial and directional differences of ΔPc. A single value characterizing the cap rock as for horizontal layered injection scenarios is not obtained. It is observed that a higher Young's modulus in the cap rock and/or a weak mechanical coupling between layers amplifies the maximum and minimum ΔPc values in the valley and limb, respectively. These differences in ΔPc imposed by E and μ are further amplified by different stress regimes. The more compressional the stress regime is,the larger the differences between the maximum and minimum ΔPc values become. The results of this study show that,in general compressional stress regimes yield the largest magnitudes of ΔPc and extensional stress regimes provide the lowest values of ΔPc for anticline formations. Yet this conclusion has to be considered with care when folded anticline layers are characterized by flexural slip and the friction coefficient between layers is low,i.e. μ=0.1. For such cases of weak mechanical coupling, ΔPc magnitudes may range from 0MPa to 27MPa,indicating imminent risk of fault reactivation in the cap rock.
A. Eckert et al., "Numerical Estimates of the Maximum Sustainable Pore Pressure in Anticline Formations using the Tensor Based Concept of Pore Pressure-Stress Coupling," Journal of Rock Mechanics and Geotechnical Engineering, vol. 7, no. 1, pp. 60-72, Chinese Academy of Sciences, Feb 2015.
The definitive version is available at https://doi.org/10.1016/j.jrmge.2014.11.001
Geosciences and Geological and Petroleum Engineering
Center for High Performance Computing Research
Keywords and Phrases
Pore pressure–stress coupling; Anticlines; Stress regimes; Friction coefficient
International Standard Serial Number (ISSN)
Article - Journal
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