Abstract
We study the processes by which petroleum originates in source rock and generates a transport path enabling some of it to leave. We show that diffusion through the source rock is too slow to account for the migration of petroleum. However when kerogen converts into petroleum within pores, it expands, and this expansion is sufficient to fracture the rock around the pores. Thus the transport of petroleum depends on whether these fractures connect up to form a macroscopic transport path. We develop a simulation tool that lets us study pressurized fluid in disk-shaped domains which expand and fracture the surrounding material. Examining pairs of pressurized pores, we obtain a lower limit for critical porosity in shale rock, \(\phi _{\text {crit.}}=0.15\). When kerogen saturation exceeds this value, long-range transport paths become possible. This critical porosity is comparable to the porosities observed in immature shales.
References
Cardott BJ, Landis CR, Curtis ME (2015) Post-oil solid bitumen network in the Woodford shale, USA: a potential primary migration pathway. Int J Coal Geol 139:106–113. https://doi.org/10.1016/j.coal.2014.08.012
Chen Z, Zhao S, Xu Z, Gao J, Xu C (2011) Molecular size and size distribution of petroleum residue. Energy Fuels 25:2109–2114. https://doi.org/10.1021/ef200128m
England WA, Mackenzie AS, Mann DM, Quigley TM (1987) The movement and entrapment of petroleum fluids in the subsurface. J Geol Soc 144:327–347. https://doi.org/10.1144/gsjgs.144.2.0327
Gale JF, Laubach SE, Olson JE, Eichhuble P, Fall A (2014) Natural fractures in shale: a review and new observations. AAPG Bull 98:2165–2216. https://doi.org/10.1306/08121413151
Haider S, Patzek TW (2020) A physics based model of enhanced gas production in mudrocks. In: Proceedings of the 8th unconventional resources technology conference. https://doi.org/10.15530/urtec-2020-2985
Haider S, Patzek T, Finkbeiner T, Littke R (2022) Numerical modeling of microfracturing and primary hydrocarbon expulsion in the Jurassic Lower Tuwaiq Mountain shale: A conceptual framework. AAPG Bull. https://doi.org/10.1306/10242221068
Inan S, Yalçin MN, Mann U (1998) Expulsion of oil from petroleum source rocks: inferences from pyrolysis of samples of unconventional grain size. Org Geochem 29:45–61. https://doi.org/10.1016/s0146-6380(98)00091-6
Leythauser D, Schaefer R, Yukler A (1982) Role of diffusion in primary migration of hydrocarbons. AAPG Bull 66:408–429. https://doi.org/10.1306/03b59b2a-16d1-11d7-8645000102c1865d
Marder M, Chen C-H, Patzek T (2015) Simple models of the hydrofracture process. Phys Rev E 92:062408. https://doi.org/10.1103/physreve.92.062408
Okotie S, Ikporo B (2019) Reservoir engineering: fundamentals and applications. Springer, New York, p 223
Speight JG (1999) The chemistry and technology of petroleum. Dekker, New York, p 306
Stankiewicz A, Lonkina N, Bennett B, Wint O, Mastalerz M (2015) Kerogen density revisited: lessons from the duvernay shale. In: Unconventional resources technology conference. https://doi.org/10.2118/178647-ms
Acknowledgements
This work was mainly supported by a Competitive Research Grant from KAUST, “Numerical and Experimental Investigation of Gas Distribution, Complex Hydrofractures and the Associated Flow in the Jafurah Basin Shales: Fundamentals to Applications.” Additional support was provided by the US National Science Foundation through Award No. 1810196, Fracture and Transport Problems for Inhomogeneous Brittle Materials. The opinions expressed in this work are not necessarily shared by the National Science Foundation.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Pharr, L., Marder, M. & Patzek, T. A model of fracture-facilitated flow of hydrocarbons from petroleum source rock. Int J Fract 241, 115–119 (2023). https://doi.org/10.1007/s10704-022-00686-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10704-022-00686-4