Development of Efficiently Coupled Fluid-Flow/Geomechanics Model To Predict Stress Evolution in Unconventional Reservoirs With Complex-Fracture Geometry
- Anusarn Sangnimnuan (Texas A&M University) | Jiawei Li (Texas A&M University) | Kan Wu (Texas A&M University)
- Document ID
- Society of Petroleum Engineers
- SPE Journal
- Publication Date
- June 2018
- Document Type
- Journal Paper
- 640 - 660
- 2018.Society of Petroleum Engineers
- fracture geometry, Stress evolution, Embedding Discrete Fracture Model (EDFM), Coupled Fluid Flow and Geomechanics
- 9 in the last 30 days
- 643 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 12.00|
|SPE Non-Member Price:||USD 35.00|
Stress changes associated with reservoir depletion are often observed in the field. Stress evolution within and surrounding drainage areas can greatly affect further reservoir developments, such as completion of infill wells and refracturing. Previous studies mainly focus on biwing planar-fracture geometry, which limits the possibility of investigating stress evolution caused by complex-fracture geometry. In this paper, we have developed a novel and efficient coupled fluid-flow/geomechanics model with an embedding-discrete-fracture model (EDFM) to characterize stress evolution associated with depletion in unconventional reservoirs with complex-fracture geometry. Coupled geomechanics/fluid flow was developed using the well-known fixed-stress-split method, which is unconditionally stable and computationally efficient to simulate how stress changes during reservoir depletion. EDFM was coupled to the model to gain capability of simulating complex-fracture geometries using structured grids. The model was validated against the classical Terzaghi (1925) and Mandel (1953) problems. Local grid refinement was used as a benchmark when comparing results from EDFM for fractures with 0 and 45° angles of inclination. After that, the model was used to analyze stress distribution and reorientation in reservoirs with three different fracture geometries: planar-fracture (90° angle of inclination), 60° inclination, and nonplanar-fracture geometries. As the pressure decreases, reservoir stresses tend to change anisotropically depending on depletion area. The principal stress parallel to the initial fracture reduces faster than the orthogonal one as a function of time. The decrease rate of principal stresses is distinct for different shapes of depleted areas created by different fracture geometries. The rectangular shape produced by the planar-fracture geometry yields the largest stress-reorientation area for a variety of differential-stress (DS) values (difference between two horizontal principal stresses). The squared shape produced by nonplanar-fracture geometry yields stress reorientation only for low DS. The results indicate that created fracture geometry has a significant effect on stress distribution and reorientation induced by depletion. To the best of our knowledge, this is the first time a coupled fluid-flow/geomechanics model incorporated with EDFM has been developed to efficiently calculate stress evolution in reservoirs with complex-fracture geometry. Characterization of stress evolution will provide critical guidelines for optimization of completion designs and further reservoir development.
|File Size||2 MB||Number of Pages||21|
Bai, M. 1999. On Equivalence of Dual-Porosity Poroelastic Parameters. J. Geophys. Res. Sol. Ea. 104 (B5): 10461–10466. https://doi.org/10.1029/1999JB900072.
Biot, M. A. 1941. General Theory of Three-Dimensional Consolidation. J. Appl. Phys. 12 (2): 155–164. https://doi.org/10.1063/1.1712886.
Biot, M. A. 1955. Theory of Elasticity and Consolidation for a Porous Anisotropic Solid. J. Appl. Phys. 26 (2): 182–185. https://doi.org/10.1063/1.1721956.
Cipolla, C. L., Fitzpatrick, T., Williams, M. J. et al. 2011. Seismic-to-Simulation for Unconventional Reservoir Development. Presented at the SPE Reservoir Characterisation and Simulation Conference and Exhibition, Abu Dhabi, 9–11 October. SPE-146876-MS. https://doi.org/10.2118/146876-MS.
Cryer, C. W. 1963. A Comparison of the Three-Dimensional Consolidation Theories of Biot and Terzaghi. The Quarterly Journal of Mechanics and Applied Mathematics 16 (4): 401–412. https://doi.org/10.1093/qjmam/16.4.401.
Dean, R. H., Gai, X., Stone, C. M. et al. 2006. A Comparison of Techniques for Coupling Porous Flow and Geomechanics. SPE J. 11 (1): 132–140. SPE-79709-PA. https://doi.org/10.2118/79709-PA.
Du, S., Liang, B., and Lin, Y. 2017. Field Study: Embedded Discrete Fracture Modeling With Artificial Intelligence in Permian Basin for Shale Formation. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 9–11 October. SPE-187202-MS. https://doi.org/10.2118/187202-MS.
Gupta, J., Zielonka, M., Albert, R. A. et al. 2012. Integrated Methodology for Optimizing Development of Unconventional Gas Resources. Presented at the SPE Hydraulic Fracturing Technology Conference, The Woodlands, Texas, 6–8 February. SPE-152224-MS. https://doi.org/10.2118/152224-MS.
Jasak, H. and Weller, H. 2000. Finite Volume Methodology for Contact Problems of Linear Elastic Solids. Oral presentation given at the 3rd International Conference of Croatian Society of Mechanics, Cavtat, Croatia.
Jha, B. and Juanes, R. 2014. Coupled Multiphase Flow and Poromechanics: A Computational Model of Pore Pressure Effects on Fault Slip and Earthquake Triggering. Water Resour. Res. 50 (5): 3776–3808. https://doi.org/10.1002/2013WR015175.
Kim, J., Tchelepi, H. A., and Juanes, R. 2011a. Stability and Convergence of Sequential Methods for Coupled Flow and Geomechanics: Drained and Undrained Splits. Comput. Meth. Appl. Mech. Eng. 200 (23–24): 2094–2116. https://doi.org/10.1016/j.cma.2011.02.011.
Kim, J., Tchelepi, H. A., and Juanes, R. 2011b. Stability and Convergence of Sequential Methods for Coupled Flow and Geomechanics: Fixed-Stress and Fixed-Strain Splits. Comput. Meth. Appl. Mech. Eng. 200 (13–16): 1591–1606. https://doi.org/10.1016/j.cma.2010.12.022.
Kim, J., Tchelepi, H. A., and Juanes, R. 2011c. Stability, Accuracy, and Efficiency of Sequential Methods for Coupled Flow and Geomechanics. SPE J. 16 (2): 249–262. SPE-119084-PA. https://doi.org/10.2118/119084-PA.
Kim, J., Tchelepi, H. A., and Juanes, R. 2013. Rigorous Coupling of Geomechanics and Multiphase Flow With Strong Capillarity. SPE J. 18 (6): 1123–1139. SPE-141268-PA. https://doi.org/10.2118/141268-PA.
Lee, I. S. 2008. Computational Techniques for Efficient Solution of Discretized Biot’s Theory for Fluid Flow in Deformable Porous Media. PhD dissertation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia.
Li, L. and Lee, S. H. 2008. Efficient Field-Scale Simulation of Black Oil in a Naturally Fractured Reservoir Through Discrete Fracture Networks and Homogenized Media. SPE Res Eval & Eng 11 (4): 750–758. SPE-103901-PA. https://doi.org/10.2118/103901-PA.
Mandel, J. 1953. Consolidation des sols (étude mathématique). Geotechnique 3 (7): 287–299. https://doi.org/10.1680/geot.19126.96.36.1997.
Peaceman, D. W. 1993. Representation of a Horizontal Well in Numerical Reservoir Simulation. SPE Advanced Technology Series 1 (1): 7–16. SPE-21217-PA. https://doi.org/10.2118/21217-PA.
Ren, G., Jiang, J., and Younis, R. M. 2017. Fully-Coupled XFEM-EDFM Hybrid Model for Geomechanics and Flow in Fractured Reservoirs. Presented at the SPE Reservoir Simulation Conference, Montgomery, Texas, 20–22 February. SPE-182726-MS. https://doi.org/10.2118/182726-MS.
Roussel, N. P., Florez, H., and Rodriguez, A. A. 2013. Hydraulic Fracture Propagation From Infill Horizontal Wells. Presented at the SPE Annual Technical Conference and Exhibition, New Orleans, 30 September–2 October. SPE-166503-MS. https://doi.org/10.2118/166503-MS.
Safari, R., Lewis, R., Ma, X. et al. 2015. Fracture Curving Between Tightly Spaced Horizontal Wells. Presented at the Unconventional Resources Technology Conference, San Antonio, Texas, 20–22 July. URTEC-2149893-MS. https://doi.org/10.15530/URTEC-2015-2149893.
Skempton, A. W. 1954. The Pore Pressure Coefficients A and B. Geotechnique 4 (4): 143–147. https://doi.org/10.1680/geot.19188.8.131.52.
Tang, T., Hededal, O., and Cardiff, P. 2015. On Finite Volume Method Implementation of Poro-Elasto-Plasticity Soil Model. Int. J. Numer. Anal. Meth. Geomech. 39 (13): 1410–1430. https://doi.org/10.1002/nag.2361.
Terzaghi, K. 1925. Erdbaumechanik auf Bodenphysikalischer Grundlage. Vienna, Austria: Franz Deuticke.
Wang, B. 2014. Parallel Simulation of Coupled Flow and Geomechanics in Porous Media. PhD dissertation, the University of Texas at Austin, Austin, Texas.
Xu, Y. 2015. Implementation and Application of the Embedded Discrete Fracture Model (EDFM) for Reservoir Simulation in Fractured Reservoirs. PhD dissertation, the University of Texas at Austin, Austin, Texas.