A Numerical Model for Caprock Analysis for Subsurface Gas Storage Applications

M. Rajabi, H. Salari Rad, M. S. Masoudian

Abstract


In considering a site for gas storage, it will be important to evaluate the effects of gas storage on the formation, so as to minimize the risk of a breach occurring in the system. Gas injection will result in an increase in formation fluid pressure, especially around the injection source, which in turn results in redistribution of the stress field. The induced deformations within the reservoir can potentially result in a damage zone within the caprock formation. This mechanical failure may involve shear along many of the existing fractures or creation of new fractures that reduce the sealing properties of the caprock system. The main objective of this paper is to develop a model to estimate the growth and extension of cracks in the caprock. In order to achieve this, the smeared crack approach is used to model the process of cracking in the caprock. Smeared cracking is a continuum approach for damage mechanics which is based on the idea that a crack is modeled by modifying the strength and stiffness of the material. The main model presented in this paper has three sub-models, which are the reservoir model, the caprock model and the smeared crack model. The reservoir model is a simplified coupled hydro-mechanical model that numerically simulates the radial fluid flow and analytically estimates the associated stress and strain within the reservoir. The results of the reservoir model are used as boundary conditions for the caprock model that estimates the stress and strain within the sealing caprock due to the deformation of the reservoir. Using the calculated stress and strain, the smeared crack model predicts the growth and extension of cracks within the caprock. The caprock is assumed to be initially crack free and impermeable. The developed model is then used to study the Yort-e-shah aquifer caprock in Iran to predict the growth and extension of cracks.


Keywords


caprock integrity; smeared crack; reservoir geomechanic;Yort-e-shah aquifer

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References


M. S. Masoudian, D. W. Airey, A. El-Zein, “Mechanical and flow behaviours and their interactions in coalbed geosequestration of CO2”, Geomechanics and Geoengineering: An International Journal, Vol. 8, No. 4, pp. 229-243, 2013

M. S. Masoudian, “Multiphysics of carbon dioxide sequestration in coalbeds: A review with a focus on geomechanical characteristics of coal”, Journal of Rock Mechanics and Geotechnical Engineering, Vol. 8, No. 1, pp. 93-112, 2016

J. A. Jimenez, R. J. Chalaturnyk, “Integrity of bounding seals for geological storage of greenhouse gases”, SPE/ISRM Rock Mechanics Conference, 2002

F. Liu, P. Lu, C. Griffith, S. W. Hedges, Y. Soong, H. Hellevang, C. Zhu, “CO2–brine–caprock interaction: Reactivity experiments on Eau Claire shale and a review of relevant literature”, International Journal of Greenhouse Gas Control, Vol. 7, No.1, pp. 153-167, 2012

Z. Szabo, H. Hellevang, C. Kiraly, E. Sendula, P. Konya, G. Falus, S. Torok, C. Szabo, “Experimental-modelling geochemical study of potential CCS caprocks in brine and CO2-saturated brine”, International Journal of Greenhouse Gas Control, Vol. 44, No.1, pp. 262-275, 2016

J. Rutqvist, J. T. Birkholzer, C. F. Tsang, “Coupled reservoir–geomechanical analysis of the potential for tensile and shear failure associated with CO2 injection in multilayered reservoir–caprock systems”, International Journal of Rock Mechanics and Mining Sciences, Vol. 45, No 2, pp. 132-143, 2008

M. Karimnezhad, H. Jalalifar, M. Kamari, “Investigation of caprock integrity for CO2 sequestration in an oil reservoir using a numerical method”, Journal of Natural Gas Science and Engineering, Vol. 21, No. 1, pp. 1127-1137, 2014

D. Dempsey, S. Kelkar, R. Pawar, E. Keating, D. Coblentz, “Modelling caprock bending stresses and their potential for induced seismicity during CO2 injection”, International Journal of Greenhouse Gas Control, Vol. 22, No.1, pp. 223-236, 2014

B. Orlic, B. Wassing, “A study of stress change and fault slip in producing gas reservoirs overlain by elastic and viscoelastic caprocks”, Rock Mechanics and Rock Engineering, Vol. 46, No. 3, pp. 421–435, 2013

R. Shukla, P. Ranjith, A. Haque, X. Choi, “A review of studies on CO2 sequestration and caprock integrity”, Fuel, Vol. 89, No. 10, pp. 2651-2664, 2010

O. R. Harvey, N. P. Qafoku, K. J. Cantrell, G. Lee, J. E. Amonette, C. F. Brown, “Geochemical implications of gas leakage associated with geologic CO2 storage—a qualitative review”, Environmental Science & Technology, Vol. 47, No. 1, pp. 23-36, 2013

J. Song, D. Zhang, “Comprehensive review of caprock-sealing mechanisms for geologic carbon sequestration”, Environmental Science & Technology, Vol. 47, No. 1, pp. 9-22, 2013

E. Detournay, “Propagation regimes of fluid-driven fractures in impermeable rocks”, International Journal of Geomechanics, Vo. 4, No. 1, pp. 35-45, 2004

A. Bunger, E. Detournay, R. Jeffrey, “Crack tip behaviour in near-surface fluid-driven fracture experiments”, Comptes Rendus Mecanique, Vol. 333, No. 4, pp. 299-304, 2005

E. Dontsov, “Propagation regimes of buoyancy-driven hydraulic fractures with solidification”, Journal of Fluid Mechanics, Vol. 797, No. 1, pp. 1-28, 2016

T. Mohammadnejad, J. Andrade, “Numerical modeling of hydraulic fracture propagation, closure and reopening using XFEM with application to in-situ stress estimation”, International Journal for Numerical and Analytical Methods in Geomechanics, Vol. 40, No. 15, pp. 2033-2060, 2016

A. Abdollahipour, M. Fatehi Marji, A. Yarahmadi Bafghi, J. Gholamnejad, “DEM simulation of confining pressure effects on crack opening displacement in hydraulic fracturing”, International Journal of Mining Science and Technology, Vol. 26, No. 4, pp. 557-561, 2016

J. G. Rots, J. Blaauwendraad, “Crack models for concrete, discrete or smeared? Fixed, multi-directional or rotating?”, Heron, Vol. 34, No. 1, pp. 3-59, 1989

Y. R. Rashid, “Ultimate strength analysis of prestressed concrete pressure vessels”, Nuclear Engineering and Design, Vol. 7, No. 4, pp. 334-344, 1968

C. Meyer, H. Okamura, Finite element analysis of reinforced concrete structures, ASCE, New York, 1986

M. A. Hussain, S. L. Pu, J. Underwood, Strain-Energy-Release Rate for a Crack under Combined Mode I and Mode II, ASTM-STP-560, pp. 2–28, 1974

A. Hillerborg, M. Modeer, P. E. Petersson, “Analysis of crack formation and crack growth in concrete by means of fracture mechanics and finite elements”, Cement and Concrete Research, Vol. 6, No.6, pp. 773–782, 1976

C. Betegon, J. W. Hancock, “Two-parameter characterization of elastic-plastic crack-tip fields”, Journal of Applied Mechanics, Vol. 58, No. 1, pp. 104–110, 1991

Y. Hu, G. Chen, W. Cheng, Z. Yang, “Simulation of hydraulic fracturing in rock mass using a smeared crack model”, Computers and structures journal, Vol. 137, pp. 72-77, 2014

S. Esperancinha, “Fracture Potential of Evaporite Seals”, European Regional Conference and Exhibition, Lisbon, Portugal, 2015

ABAQUS, CAE User's Guide, and ABAQUS Analysis User's Guide, version 6.13, Dassault Systemes Simulia Corp., Providence, RI, U.S.A, 2015

M. S. Masoudian, D. W. Airey, A. El-Zein, “The role of coal seam properties on coupled processes during CO2 sequestration: A parametric study”, Greenhouse Gases: Science and Technology, Vol. 6, No. 4, pp. 492-518, 2016

M. S. Masoudian, D. W. Airey, A. El-Zein, “Modelling stress and strain in coal seams during CO2 injection incorporating the rock–fluid interactions”, Computers and Geotechnics, Vol. 76, No. 1, pp. 51–60, 2016

M. S. Masoudian, D. W. Airey, A. El-Zein, “A chemo-poro-mechanical model for sequestration of carbon dioxide in coalbeds”, Geotechnique, Vol. 63, No. 3, pp. 235-243, 2013

E. Fjaer, R. M. Holt, P. Horsrud, A. M. Raaen, R. Risnes, Petroleum related rock mechanics, 2nd edition, Elsevier, 2008

J. Lee, K. B. Min, J. Rutqvist, “Probabilistic analysis of fracture reactivation associated with deep underground CO2 injection”, Rock Mechanics and Rock Engineering, Vol. 46, No. 4, pp. 801-820, 2013

P. Werner, Drilling program for Yort-e-Shah well No. 4, Task Report A2.1, Sofregaz Group, Paris, 2006

S. Hangx, C. Spiers, C. Peach, Mechanical behaviour of anhydrite caprock and implications for CO2 sealing capacity, Journal of geophysical research, Vol. 115, No. 7, pp. 1-22, 2010

D. Powell, Lab investigation of Yort-e-Shah aquifer: Petrophysical core analysis study of exploration well No. 2, Task Report A10, Vol. 3, KBB Group, Hannover, 1998

K. Wiechart, Lab investigation of Yort-e-Shah aquifer: Petrophysical core analysis study of exploration well No. 2, Task Report A10, Vol. 2, KBB Group, Hannover, 1998

M. R. Esfahani, E. Kazemzadeh, J. Vali, Routine core analysis report for well No. 4 of Yort-e-Shah field, Core Research Department, Exploration & Production Research Division, Research Institute of Petroleum Industry (RIPI), Tehran, 2006

A. Fenghour, W.A. Wakeham, V. Vesovic, “The viscosity of carbon dioxide”, Journal of Physical Chemistry Reference Data, Vol. 27, No. 1, pp.31–44, 1998

R. J. Twiss, E.M. Moores, Structural geology, 2nd Ed, W. H. Freeman and Company, San Fransisco, 2006




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