Hydraulic Fracturing Process in Tight Base Shale of Asmari Formation in Ahwaz Oilfield

Document Type : Research Paper


Department of Petroleum Engineering, Ahwaz Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan, Iran


Over the years, unconventional reservoirs have not received attention in Iran in light of easy oil. The most significant oil reservoir in Iran is Asmari formation of Ahwaz oilfield which has been producing oil by natural flow potential. Due to the gradual pressure drop of Asmari formation and oil price increment, production from the base shale of this formation has been considered. However, due to the low permeability of this layer, oil production has not been achieved, and it has still remained a challenge. Production of petroleum from tight/shale rocks has become possible by hydraulic fracturing. This study has hired Asmari formation base shale as case study for hydraulic fracturing simulations. This paper is focused on a scientific process to construct a lithology-dependent one-dimensional geomechanical model in an oil well which is completed in Asmari formation. Moreover poro-elastic formulation has been used for in-situ stress determination. In addition, the tectonic stress regime has been identified as normal faulting. Afterwards, a hydraulic fracturing operation has been designed by the FracCADE simulator. During hydraulic fracturing operations, an uncontrolled-height fracture may occur due to the absence of stress-barriers in bounding layers. A hydraulic fracture was designed for a sublayer of the Asmari base shale based on the constructed profile of in-situ stresses to constrain the vertical growth. Ultimately according to the results of the simulation, it was illustrated that the designed fractures did not cross the bedding interfaces of Asmari base shale.


  1. Yu W, Sepehrnoori K (2013) Optimization of multiple hydraulically fractured horizontal wells in unconventional gas reservoirs, Journal of Petroleum Engineering, 1-16. ##
  2. Vishkai M, Wang J, Wong RC, Clarkson CR, Gates I (2017) Modeling geomechanical properties in the montney formation, Alberta, Canada, International Journal of Rock Mechanics and Mining Sciences 96, 94–105. ##
  3. Vishkai M, Gates I (2019) on multistage hydraulic fracturing in tight gas reservoirs: Montney Formation, Alberta, Canada, Journal of Petroleum Science and Engineering, 1127–1141. ##
  4. Ahmadov R (2011) Micro-textural elastic and transport properties of source rocks, PhD thesis, Stanford University.
  5. Alford J, Blyth M, Tollefsen E (2012) Sonic logging while drilling- shear answer.Schlumberger: Oilfield review 1, 4-15. ##
  6. Van D, de Pater DB, Romijn R (1998) Analysis of fracture closure in laboratory experiments, Paper SPE 47380.##
  7. Najibi A, Ghafoori M, Lashkaripour G, Asef M (2017) Reservoir geomechanical modeling: In-situ stress, pore pressure, and mud design, Journal of Petroleum Science and Engineering, 151, 31–39.##
  8. Najibi AR, Ghafoori M, Lashkaripour GR, Asef MR (2015) Empirical relations between strength and static and dynamic elastic properties of Asmari and Sarvak limestone, two main oil reservoirs in Iran, Journal of Petroleum Science and Engineering, 126, 78–82.##
  9. Zhenlin W, Ting S, Cheng F, Wei W (2018) An improved method for predicting brittleness of rocks via well logs in tight oil reservoirs, Journal of Geophysics Engineering, 15, 1042–1049.##
  10. Papanastasiou P (1997) A coupled elasto-plastic hydraulic fracturing model, International Journal of Rock Mechanics and Mining Sciences 34-240. ##
  11. Brocher TM (2005) Empirical relations between elastic wave speeds and density in the earth’s crust, Bulletin of the Seismological Society of America, 95, 2081–2092. ##
  12. Tristan E (2011) Shale Gas-an overview, IFP Technologies (Canada) INC.##
  13. Passey QR, Bohacs KM, Esch WL, Klimentidis R, Sinha S (2010) From oil-prone source rock to gas-producing shale reservoir – geologic and petrophysical characterization of unconventional shale-gas reservoirs.” CPS/SPE International Oil & Gas Conference and Exhibition. Beijing, China; 8-10 June 2010. ##
  14. Haug K, Nygaard R, Keith D (2007) Evaluation of stress and geomechanical characteristics of a potential site for CO2 geological storage in central Alberta, Canada, In: 60th Canadian Geotechnical Conference and 8th Joint CGS/IAH-CNC Ground Water Conference 21–24. ##
  15. Onyia E C (1988) Relationships between formation strength, drilling strength, and electric log properties, 63rd Ann. Tech. Conference Houston. TX. USA, 2–5. ##
  16. Fjaer E, Holt RM, Raaen AM, Risnes R (2008) Petroleum Related Rock Mechanics, Elsevier, 53. ##
  17. Kahraman S, Fener M, Kozman E (2012) Predicting the compressive and tensile strength of rocks from indentation hardness index, Journal of the Southern African Institute of Mining and Metallurgy 112, 5: 331-339.##
  18. Zang A, Stephansson O (2010) Stress field of the Earth’s crust, Springer. ##
  19. Zhang Y, Zhang J (2017) Lithology-dependent minimum horizontal stress and in-situ stress estimate Tectonophysics 703–704, 1–8. ##
  20. Ostadhassan M, Zeng Z, Zamiran S (2012) Geomechanical modeling of an anisotropic Formation-Bakken case study, 46th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics Association. ##
  21. Thiercelin M, Plumb R (1994) a core-based prediction of lithologic stress contrasts in east Texas formations, SPE Form. Eval. 9 (04), 251–258. ##
  22. Economides M J, Daniel Hill A, Christine Ehlig-Economides (1992) Petroleum production systems,  Prentice-Hall
  23. Kidambi T, Kumar G S (2016) Mechanical Earth Modeling for a vertical well drilled in a naturally fractured tight carbonate gas reservoir in the Persian Gulf, Journal of Petroleum Science and Engineering, 141, 38–51.##
  24. Anderson EM (1951) the dynamics of faulting and dyke formation with application to Britain, Oliver and Boyd, London. ##
  25. Hubbert MK, Willis DG (1957) Underground Waste Management and Environmental Implications-- Mechanics of hydraulic fracturing, Petroleum Transactions AIME, AAPG, 210, 153–168. ##
  26. Fung R L, Vilayakumar S, Cormack D E (1987) Calculation of vertical fracture containment in layered formations, SPE 14707 SPE Form. Eval. 2 (04), 518–523. ##
  27. Warpinski NR, Schmidt RA, Northrop DA (1982) In situ stresses: the predominant influence on hydraulic fracture containment, Journal of Petroleum Technology, 34 653–664.##
  28. Guo F, Morgenstern NR, Scott JD (1993) an experimental investigation into hydraulic fracture propagation - part 2 single well tests, International Journal of Rock Mechanics and Mining Sciences 30 189–202. ##
  29. Zhang Y, Zhang J, Yuan B, Yin S (2018) In-situ stresses controlling hydraulic fracture propagation and fracture breakdown pressure, Journal of Petroleum Science and Engineering, 164 164–173.##
  30. Economides MJ, Nolte KG (2000) Reservoir Stimulation 3th edition, John Wiley & Sons, ISBN 0 471 49192 6. ##