Pressure-Transient Characteristics of Fractured Horizontal Wells in Unconventional Shale Reservoirs With Construction of Data-Constrained Discrete-Fracture Network
- Jianlei Sun (Texas A&M University) | David Schechter (Texas A&M University)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- February 2018
- Document Type
- Journal Paper
- 21 - 31
- 2018.Society of Petroleum Engineers
- Pressure Transient Analysis, Fractured Horizontal Wells, Unconventional Shale Reservoirs, Complex Fracture Networks
- 14 in the last 30 days
- 366 since 2007
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Unconventional shale reservoirs require massive and multistage hydraulically fractured horizontal wells to produce economically. Induced hydraulic fractures interacting with in-situ natural fractures result in complex or discrete fracture networks (DFNs). Even though well-testing characteristics in fractured reservoirs with vertical wells have been investigated extensively, there is a lack of good understanding of well-testing response for hydraulically fractured horizontal wells in complex fracture networks.
First, three practical approaches are presented regarding how to generate complex fracture networks in the context of developing unconventional shale reservoirs with hydraulically fractured horizontal wells. Complex fracture networks can be generated (1) from stochastic algorithms that enter fracture density, length, and strike distributions, or (2) from the flowing-producing DFN (FPDFN) area that is constrained by microseismic information, or (3) from digitization of realistic outcrop maps. Then, new unstructured fracture gridding and discretization techniques specially tailored for complex fracture networks are developed to handle nonuniform fracture aperture, extensive fracture clustering, and nonorthogonal fracture intersections. Finally, the numerical simulation of pressure buildup is performed in complex fracture networks that are generated from three proposed approaches with both synthetic and field examples. Flow regimes are identified and are discussed on the basis of pressure-derivative plots.
Complex fracture networks show that the most representative characteristics are formation/fracture bilinear flow and formation linear-flow regimes. The appearance of the bilinear-flow regime during early period might not be clear because of the impact of the wellbore-storage effect as both the wellbore volume and the volume of the larger natural fractures in communication with the wellbore. In addition, the microseismic-based approach reduces the uncertainties of fracture characterization with percentiles of FP-DFN areas. The pressure-buildup response observed clearly indicates that the higher the percentiles of FP-DFN areas (or intense naturally fractured portion of the completion), the lower the pressure difference and derivative curves. Fracture mineralization affects pressure-buildup responses significantly. The decrease in nonuniform fracture apertures causes pressure-diagnostic plots to shift upward. The effect of boundary in the outcrop-based complex fracture network shows an early deviation from the formation linear-flow regime. No classic dual-porosity behavior is observed in all cases to quantify related parameters.
Three practical techniques are proposed to generate complex fracture networks. Pressure-transient characteristics are identified and summarized. Further research areas are discussed and highlighted. The combination of techniques such as microseismic, horizontal core, production logging or some method to characterize the fracture network can be used to close the loop between the inferred network and the response that it should exhibit during pressure-transient analysis.
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Al-Kobaisi, M., Ozkan, E., and Kazemi, H. 2006. A Hybrid Numerical/Analytical Model of a Finite-Conductivity Vertical Fracture Intercepted by a Horizontal Well. SPE Res Eval & Eng 9 (4): 345–355. SPE-92040-PA. https://doi.org/10.2118/92040-PA.
Biryukov, D. and Kuchuk, F. J. 2015. Pressure Transient Behavior of Horizontal Wells Intersecting Multiple Hydraulic Fractures in Naturally Fractured Reservoirs. Transport in Porous Media 110 (3): 369–408. https://doi.org/10.1007/s11242-015-0554-1.
Brown, M., Ozkan, E., Raghavan, R. et al. 2011. Practical Solutions for Pressure-Transient Responses of Fractured Horizontal Wells in Unconventional Shale Reservoirs. SPE Res Eval & Eng 14 (6): 663–676. SPE-125043-PA. https://doi.org/10.2118/125043-PA.
Chen, C.-C. and Rajagopal, R. 1997. A Multiply-Fractured Horizontal Well in a Rectangular Drainage Region. SPE J. 2 (4): 455–465. SPE-37072-PA. https://doi.org/10.2118/37072-PA.
Cinco-Ley, H., Samaniego-V, F., and Dominguez, A. N. 1978. Transient Pressure Behavior for a Well With a Finite-Conductivity Vertical Fracture. SPE J. 18 (4): 253–264. SPE-6014-PA. https://doi.org/10.2118/6014-PA.
Cinco-Ley, H. and Samaniego-V, F. 1981. Transient Pressure Analysis for Fractured Wells. J Pet Technol 33 (9): 1749–1766. SPE-7490-PA. https://doi.org/10.2118/7490-PA.
Cipolla, C. L., Warpinski, N. R., and Mayerhofer, M. J. 2008. Hydraulic Fracture Complexity: Diagnosis, Remediation, and Exploitation. Presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition, Perth, Australia, 20–22 October. SPE-115771-MS. https://doi.org/10.2118/115771-MS.
Cossio, M., Moridis, G., and Blasingame, T. A. 2013. A Semianalytic Solution for Flow in Finite-Conductivity Vertical Fractures by Use of Fractal Theory. SPE J. 18 (1): 83–96. SPE-153715-PA. https://doi.org/10.2118/153715-PA.
Dahi Taleghani, A. and Olson, J. E. 2013. How Natural Fractures Could Affect Hydraulic-Fracture Geometry. SPE J. 19 (1): 161–171. SPE-167608-PA. https://doi.org/10.2118/167608-PA.
Ferrill, D. A., McGinnis, R. N., Morris, A. P. et al. 2014. Control of Mechanical Stratigraphy on Bed-Restricted Jointing and Normal Faulting: Eagle Ford Formation, South-Central Texas. AAPG Bull. 98 (11): 2477–2506.
Fisher, M. K., Wright, C. A., Davidson, B. M. et al. 2005. Integrating Fracture Mapping Technologies to Improve Stimulations in the Barnett Shale. SPE Prod & Fac 20 (2): 85–93. SPE-77441-PA. https://doi.org/10.2118/77441-PA.
Gamboa, E., Sun, J., and Schechter, D. S. 2016. Reducing Uncertainties of Fracture Characterization on Production Performance by Incorporating Microseismic and Core Analysis Data. Presented at the SPE Asia Pacific Hydraulic Fracturing Conference, Beijing, 24–26 August. SPE-181785-MS. https://doi.org/10.2118/181785-MS.
Heidari Sureshjani, M. and Clarkson, C. R. 2015. An Analytical Model for Analyzing and Forecasting Production From Multifractured Horizontal Wells With Complex Branched-Fracture Geometry. SPE Res Eval & Eng 18 (3): 356–374. SPE-176025-PA. https://doi.org/10.2118/176025-PA.
Jia, P., Cheng, L., Huang, S. et al. 2015. Production Simulation of Complex Fracture Networks for Shale Gas Reservoirs Using a Semi-Analytical Model. Presented at the SPE Asia Pacific Unconventional Resources Conference and Exhibition, Brisbane, Australia, 9–11 November. SPE-176981-MS. https://doi.org/10.2118/176981-MS.
Kim, T. H. and Schechter, D. 2009. Estimation of Fracture Porosity of Naturally Fractured Reservoirs With No Matrix Porosity Using Fractal Discrete Fracture Networks. SPE Res Eval & Eng 12 (2): 232–242. SPE-110720-PA. https://doi.org/10.2118/110720-PA.
Larsen, L. and Hegre, T. M. 1994. Pressure Transient Analysis of Multifractured Horizontal Wells. Presented at the SPE Annual Technical Conference and Exhibition, New Orleans, 25–28 September. SPE-28389-MS. https://doi.org/10.2118/28389-MS.
Lee, S.-T. and Brockenbrough, J. R. 1986. A New Approximate Analytic Solution for Finite-Conductivity Vertical Fractures. SPE Form Eval 1 (1): 75–88. SPE-12013-PA. https://doi.org/10.2118/12013-PA.
Luo, H.-S., Wang, X.-H., and Quintard, M. 2008. Adaptive Mesh Refinement for One-Dimensional Three-Phase Flows in Heterogeneous Fractured Porous Media. Numerical Heat Transfer, Part B: Fundamentals 54 (6): 476–498. https://doi.org/10.1080/10407790802424105.
Mayerhofer, M. J., Lolon, E., Warpinski, N. R. et al. 2008. What Is Stimulated Rock Volume? Presented at the SPE Shale Gas Production Conference, Fort Worth, Texas, USA, 16–18 November. SPE-119890-MS. https://doi.org/10.2118/119890-MS.
Medeiros, F., Ozkan, E., and Kazemi, H. 2008. Productivity and Drainage Area of Fractured Horizontal Wells in Tight Gas Reservoirs. SPE Res Eval & Eng 11 (5): 902–911. SPE-108110-PA. https://doi.org/10.2118/108110-PA.
Ozkan, E., Brown, M. L., Raghavan, R. et al. 2011. Comparison of Fractured-Horizontal-Well Performance in Tight Sand and Shale Reservoirs. SPE Res Eval & Eng 14 (2): 248–259. SPE-121290-PA. https://doi.org/10.2118/121290-PA.
Pan, Y., Hui, M.-H., Narr, W. et al. 2016. Integration of Pressure-Transient Data in Modeling Tengiz Field, Kazakhstan—A New Way to Characterize Fractured Reservoirs. SPE Res Eval & Eng 19 (1): 5–17. SPE-165322-PA. https://doi.org/10.2118/165322-PA.
Raghavan, R. S., Chen, C.-C., and Agarwal, B. 1997. An Analysis of Horizontal Wells Intercepted by Multiple Fractures. SPE J. 2 (3): 1–13. SPE-27652-PA. https://doi.org/10.2118/27652-PA.
Rodriguez, F., Horne, R. N., and Cinco-Ley, H. 1984. Partially Penetrating Vertical Fractures: Pressure Transient Behavior of a Finite-Conductivity Fracture. Presented at the SPE Annual Technical Conference and Exhibition, Houston, 16–19 September. SPE-13057-MS. https://doi.org/10.2118/13057-MS.
Samandarli, O., McDonald, B., Barzola, G. et al. 2014. Understanding Shale Performance: Performance Analysis Workflow With Analytical Models in Eagle Ford Shale Play. Presented at the SPE Unconventional Resources Conference, The Woodlands, Texas, USA, 1–3 April. SPE-169004-MS. https://doi.org/10.2118/169004-MS.
Stalgorova, K. and Mattar, L. 2013. Analytical Model for Unconventional Multifractured Composite Systems. SPE Res Eval & Eng 16 (3): 246–256. SPE-162516-PA. https://doi.org/10.2118/162516-PA.
Sun, J. and Schechter, D. S. 2015. Optimization-Based Unstructured Meshing Algorithms for Simulation of Hydraulically and Naturally Fractured Reservoirs With Variable Distribution of Fracture Aperture, Spacing, Length, and Strike. SPE Res Eval & Eng 18 (4): 463–480. SPE-170703-PA. https://doi.org/10.2118/170703-PA.
Wan, Y., Liu, Y., Ouyang, W. et al. 2016. Numerical Investigation of Dual-Porosity Model With Transient Transfer Function Based on Discrete-Fracture Model. Applied Mathematics and Mechanics 37 (5): 611–626. https://doi.org/10.1007/s10483-016-2075-8.
Wang, W., Su, Y., Sheng, G. et al. 2015. A Mathematical Model Considering Complex Fractures and Fractal Flow for Pressure Transient Analysis of Fractured Horizontal Wells in Unconventional Reservoirs. Journal of Natural Gas Science and Engineering 23: 139–147. https://doi.org/10.1016/j.jngse.2014.12.011.
Warpinski, N. R., Mayerhofer, M. J., Vincent, M. C. et al. 2008. Stimulating Unconventional Reservoirs: Maximizing Network Growth While Optimizing Fracture Conductivity. Presented at the SPE Unconventional Reservoirs Conference, Keystone, Colorado, USA, 10–12 February. SPE-114173-MS. https://doi.org/10.2118/114173-MS.
Weng, X., Kresse, O., Cohen, C. et al. 2011. Modeling of Hydraulic-Fracture-Network Propagation in a Naturally Fractured Formation. SPE Prod & Oper 26 (4): 368–380. SPE-140253-PA. https://doi.org/10.2118/140253-PA.