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Productivity analysis of a fractured horizontal well in a shale gas reservoir based on discrete fracture network model

  • Yu-long Zhao (赵玉龙)Email author
  • Nan-ying Li (李南颖)
  • Lie-hui Zhang (张烈辉)
  • Rui-han Zhang (张芮菡)
Article
  • 6 Downloads

Abstract

Treating horizontal wells with massive hydraulic fracturing technology has made shale gas reservoirs economical to develop, and sometimes complex induced fractures are created during the fracturing process. Reports describing fluid flow characteristics in such formations are rare. In this study, a numerical method based on a finite element method (FEM) was developed for productivity analysis of a horizontal well in a shale gas reservoir with complex fractures. The proposed method takes into account the adsorbed gas and complex hydraulic fracture branches. To make the problem more tractable, the dimension of the fracture system is reduced from 2D to 1D based on the discrete fracture network (DFN) model. The accuracy of the new method is verified by comparing its results with those of Saphir commercial software. Finally, the productivity of fractured horizontal wells in shale gas reservoirs with complex fractures systems are obtained and analyzed. Results show that if a well is produced with a constant bottomhole pressure, the well productivity is much greater due to the existence of fracture branches that can increase the stimulated reservoir volume (SRV). In addition, the number of hydraulic fractures (Nf) and fracture half-lengths (Lf) have an important influence on the well’s productivity. The larger the Nf and Lf are, the greater the well productivity will be. The existence of adsorbed gas can markedly improve well productivity, and the greater the Langmuir volume is, the greater the productivity will be. The conclusions drawn by this study can provide guidance for the development of unconventional shale gas reservoirs.

Key words

fractured horizontal well DFN model FEM productivity analysis shale gas reservoir 

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References

  1. [1]
    Ozkan E., Raghavan R. Modeling of fluid transfer from shale matrix to fracture network [C]. Proceedings SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September, 2010.Google Scholar
  2. [2]
    Li L., Lee S. H. Efficient Field–Scale Simulation of black oil in a naturally fractured reservoir through discrete fracture networks and homogenized media [J]. SPE Reservoir Evaluation & Engineering, 2008, 11(4): 750–758.CrossRefGoogle Scholar
  3. [3]
    Zhao Y. L., Zhang L. H., Zhao J. Z. et al. “Triple porosity” modeling of transient well test and rate decline analysis for multi–fractured horizontal well in shale gas reservoirs [J]. Journal of Petroleum Science and Engineering, 2013, 110: 253–262.CrossRefGoogle Scholar
  4. [4]
    Zhao Y. L., Zhang L. H., Luo J. X. et al. Performance of fractured horizontal well with stimulated reservoir volume in unconventional gas reservoir [J]. Journal of Hydrology, 2014, 512: 447–456.CrossRefGoogle Scholar
  5. [5]
    Zhao Y. L., Zhang L. H., Xiong Y. et al. Pressure response and production performance for multi–fractured horizontal wells with complex seepage mechanism in box–shaped shale gas reservoir [J]. Journal of Natural Gas Science and Engineering, 2016, 32: 66–80.CrossRefGoogle Scholar
  6. [6]
    Brown M., Ozkan E., Raghavan R. et al. Practical solutions for pressure transient responses of fractured horizontal wells in unconventional shale reservoirs [C]. Proceedings SPE Annual Technical Conference and Exhibition, New Orleans, 2009.Google Scholar
  7. [7]
    Lin J. J., Zhu D. Predicting well performance in complex fracture systems by slab source method [C]. Proceedings SPE Hydraulic Fracturing Technology Conference, 6–8 February, The Woodlands, Texas, USA, 2012.Google Scholar
  8. [8]
    Rasheed, O.B. Rate transient analysis and investigation of unit slopes in multistage hydraulically fractured tight carbonate reservoirs[C]. Proceedings SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, Indonesia, 2011.Google Scholar
  9. [9]
    Xiao C., Tian L., Yang Y. K. et al. Comprehensive application of semi–analytical PTA and RTA to quantitatively determine abandonment pressure for CO2 storage in depleted shale gas reservoirs [J]. Journal of Petroleum Science and Engineering, 2016, 146: 813–831CrossRefGoogle Scholar
  10. [10]
    Mi L. D. Investigation of shale gas numerical simulation method based on discrete fracture network model [J]. Natural Gas Geoscicence, 2014, 25(11): 1795–1803(in Chinese).MathSciNetGoogle Scholar
  11. [11]
    Cipolla C. L., Lolon E. P., Mayerhofer M. J. Reservoir modeling and production evaluation in shale gas reservoirs [C]. Proceedings SPE International Petroleum Technology Conference, Doha, Qatar, 2009.Google Scholar
  12. [12]
    Zhang R. H., Zhang L. H., Luo J. X. et al. Numerical simulation of water flooding in natural fractured reservoirs based on control volume finite element method [J]. Journal of Petroleum Science and Engineering, 2016, 146: 1211–1225.CrossRefGoogle Scholar
  13. [13]
    Zhang R. H., Zhang L. H., Wang R. H. et al. Research on transient flow theory of a multiple fractured horizontal well in a composite shale gas reservoir based on the finite–element method [J]. Journal of Natural Gas Science and Engineering, 2016, 33: 587–598CrossRefGoogle Scholar
  14. [14]
    Li N. Y. Investigation of shale gas productivity analysis based on the discrete fracture network model [M]. Master Thesis, Chengdu, China: Southwest Petroleum University, 2016(in Chinese).Google Scholar
  15. [15]
    Wu K., Chen Z., Li X. F. et al. A model for multiple transport mechanisms through nanopores of shale gas reservoirs with real gas effect–adsorption–mechanic coupling [J]. International Journal of Heat and Mass Transfer, 2016, 93: 408–426CrossRefGoogle Scholar
  16. [16]
    Zhao Y. L., Zhang, L. H., Shan B. C. Mathematical model of fractured horizontal well in shale gas reservoir with rectangular stimulated reservoir volume [J]. Journal of Natural Gas Science and Engineering, 2018, 59: 67–79CrossRefGoogle Scholar
  17. [17]
    Tan X. H., Li X. P. Transient flow model and pressure dynamic features of tree–shaped fractal reservoirs [J]. Journal of Hydrodynamics, 2014, 26: 654CrossRefGoogle Scholar
  18. [18]
    Tan X. H., Li X. P., Liu J. Y. et al. A simulation method for permeability of porous media based on multiple fractal model [J]. International Journal of Engineering Science, 2015, 95: 76–84.CrossRefzbMATHGoogle Scholar

Copyright information

© China Ship Scientific Research Center 2018

Authors and Affiliations

  • Yu-long Zhao (赵玉龙)
    • 1
    Email author
  • Nan-ying Li (李南颖)
    • 2
  • Lie-hui Zhang (张烈辉)
    • 1
  • Rui-han Zhang (张芮菡)
    • 1
  1. 1.State Key Laboratory of Oil and Gas Reservoir Geology and ExploitationSouthwest Petroleum UniversityChengduChina
  2. 2.Southwest Oil and Gas BranchSINOPECChengduChina

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