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Papers by Patzek et al. on US shale plays

I've been receiving recurring requests for the links to our publications on shales.  Thus, I have decided to put our shale story together, and update it in the future as the new papers are published. So far, this story consists of 29 papers and one patent published, and eight papers are pending. 

Our goal is to describe the well-by-well histories and possible futures of all major US shale plays, starting from the earliest one, the Barnett. To achieve this goal, we have been using a physics-based scaling of individual well production and the generalized extreme value (GEV) statistics for spatio-temporal cohorts of wells.  

As an aside, out of 15 or so, only three of our paper submissions to the Society of Petroleum Engineers (SPE) conferences have been accepted since 2017, and we have given up on the SPE, of which I am a Distinguished Member with 38 years in the Society under my belt.  It is quite sad for me personally, but SPE has been in disarray for several years.

Except for the SPE and OGJ papers that reside behind paywalls, all our other papers are open access, and you can download their pdf files by clicking on the web links below.

Later, I will add 3-5 other papers on numerical simulations, etc.

Our 2016 paper, "Physics, fracking, fuel, and the future," made the cover.


1. "Gas production in the Barnett Shale obeys a simple scaling theory", Tad W. Patzek, Frank Male, and Michael Marder, PNAS December 3, 2013 110 (49) 19731-19736; For this paper, we received the Cozzarelli Prize  from the National Academy of Sciences for Best Paper in Engineering  in 2013.  Actually, this was a big deal.
2. "Barnett Shale in Texas: Promise and Problems", Patzek, Tadeusz, 2019,, Texas Data Repository, V1,  Presentation to BEG May 26, 2011. (I presented my late 2010 work at the Department of Petroleum and Geosystems Engineering and the Bureau of Economic Geology, at the University of Texas, Austin, but I did not succeed in conveying the importance of GEV statistics to the modeling of shale wells. Only after the PNAS paper was published three years later, people started paying attention, but it took the 2019 ACS paper to get the GEV approach out to the public.)

3. "A simple model of gas production from hydrofractured horizontal wells in shales,"  Tad Patzek; Frank Male; Michael Marder, AAPG Bulletin December 01, 2014, Vol.98, 2507-2529.,

4. SPE 187068, “Knudsen-Like Scaling May Be Inappropriate for Gas Shales,” by Tadeusz W. Patzek, SPE, prepared for the 2017 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 9–11 October. (I am proud of this wonderful little physics paper I wrote quickly as a  practical joke, never expecting it to be accepted by the SPE. I was wrong and it was. The field data and mass balances are based on the Barnett wells.  You might read this paper and glean the incredibly rich and oft-misinterpreted physics of gas flow in shales.)

5. "Field data provide estimates of effective permeability, fracture spacing, well drainage area and incremental production in gas shales," Behzad Eftekhari, Michael Marder, and Tadeusz W. Patzek, Journal of Natural Gas Science and Engineering, Volume 56, August 2018, Pages 141, (In this paper we introduced late time gas inflow from the reservoir regions exterior to a parallelepiped delineated by a horizontal well and its hydrofractures.  We have also provided field data from the Barnett wells to document this inflow.)

6. "Generalized Extreme Value Statistics, Physical Scaling, and Forecasts of Gas Production in the Barnett Shale," Tadeusz W. Patzek, Wardana Saputra, Wissem Kirati, and Michael Marder, Energy & Fuels 2019, 33, 12, 12154–12169, (In the summer of 2018, I finally updated my 2010 GEV statistics codes, and extended them to include the data-driven survival probabilities of spatio-temporal well cohorts. I shared the updated 2018 codes with my incredibly gifted PhD student, Wardana Saputra, and he took over the bulk of modeling of shales in the multiple papers that ensued, significantly extending the scope and depth of our analyzes.  Wardana has introduced the multiple spatial and temporal well cohorts, the well infill and future drilling scenarios, and well economics.)

Our Generalized Extreme Value paper made the cover of Energy & Fuels in December 2019.

7. "A Physics Based Model of Enhanced Gas Production in Mudrocks," Syed Haider and Tadeusz W. Patzek, Paper presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, Virtual, July 2020. Paper Number: URTEC-2020-2985-MS, (This is a great physics paper that shines light on the pore level mechanisms of gas recovery from shales. Syed Haider is another star student in my group at KAUST and a deep thinker.)

8. "The Key Factors That Determine the Economically Viable, Horizontal Hydrofractured Gas Wells in Mudrocks," Syed Haider, Wardana Saputra, and Tadeusz Patzek, Energies 2020, 13(9), 2348, (This paper, mostly by Syed, extends our two-parameter physics based scaling to a more complicated one that accounts for the fractal nature of the hydrofracture/natural fracture systems in mudrocks, and mass transfer between the nanoscale and several other, larger scales. We have illustrated this complex physics with the Barnett well data. This paper is a must read if you want to gain more insights into the essentially multiscale gas flow in shales.)


9. "Simple models of the hydrofracture process," M. Marder, Chih-Hung Chen, and T. Patzek, Phys. Rev. E 92, 062408, 2015, (This elegant theoretical paper predicts simultaneous growth of several competing hydrofractures.  The high-resolution data to scale the fracture growth models in this paper came from the NE Marcellus. These data were given to me by a graduate of PGE and a friend. Boy, have we used them to multiple ends, and my friend company's benefit.  I wish more of  such data were transferred from the industry to academia for mutual benefit.)

10. "Modeling Gas Adsorption in Marcellus Shale With Langmuir and BET Isotherms," Wei Yu, Kamy Sepehrnoori, Tadeusz W. Patzek, SPE Journal 21 (02): 589–600, Paper Number: SPE-170801-PA, Society of Petroleum Engineers (SPE), (This paper is based on the strong adsorption data in the graphitized nanopores in the NE Marcellus. Gas sorption is so strong that it can be modeled with the BET multilayer adsorption isotherm.  The BET model is physically incorrect, but it captures well the background nanopores feeding gas into the microfractures.)

11. SPE 180234, “Marcellus Wells: Ultimate Production Accurately Predicted From Initial Production,” by Frank Male, Michael P. Marder, John Browning, and Svetlana Ikonnikova, The University of Texas at Austin, and Tad Patzek, King Abdullah University of Science and Technology, prepared for the 2016 SPE Low- Permeability Symposium, Denver, 5–6 May,,

12. "Estimation of Effective Permeability, Fracture Spacing, Drainage Area, and Incremental Production from Field Data in Gas Shales with Nonnegligible Sorption,"  B. Eftekhari, M. Marder, T. W. Patzek, SPE Reservoir Evaluation & Engineering 23 (02): 664–683, 2020, Paper Number: SPE-199891-PA, (This paper is about late time radial inflow in the Marcellus with a strong gas adsorption in the organic nanopores.)

13. "Generalized Extreme Value Statistics, Physical Scaling and Forecasts of Gas Production in the Marcellus Shale," Keynote Lecturer, Tad Patzek, Geoscience and Geoenergy Webinar by TU Delft and Heriot Watt University, streamed live on Apr 15, 2021.

14. "Generalized Extreme Value Statistics, Physical Scaling and Forecasts of Gas Production in the Marcellus Shale," Wardana Saputra, Wissem Kirati, David Hughes, and Tadeusz Patzek, Paper BLTN21-78, in review by the AAPG Bulletin, May 2021. (For a preview of the paper content, please see the YouTube video).


The work has been completed and documented by Wardana and Wissem, but the paper proposal was soundly rejected by the organizers of the 2021 SPE URTeC conference.  We'll write the paper up later in spare time and publish it elsewhere.  

Nota bene, we always start writing a paper from the figures and their captions,  and only later weave the paper's story around the graphics.  I am under no illusion that most people will ever read our papers carefully.  Thus, I rely on the abstract, figures and conclusions to tell 70-80% of a paper's message.  We then use the supporting online materials to tell the details of a paper's story in  graphical form.  Also, with our comprehensive approach, we predict the most likely futures of a shale play in the least square sense.  As Jack Nicholson would say, "Folks, this is a good as it gets!"  Thus, some of the industry people do not appreciate our stories, simply because they are too accurate and precise, and leave too little wiggle room to snow their investors.  For example, our first Bakken paper, that appeared later in MDPI, was held up by a Houston editor of another journal for several months, until I withdrew the paper from that journal, and next day got an offer to publish it immediately from the journal's Chief Editor.  But I followed up on our threat and we lost several months.  In the end, our first Bakken paper was published as the second one.

Never mind though, the industry is now being snowed royally by a grand delusion of AI. Since the people who actually knew the scientific domain and engineering are mostly gone, they have been replaced by electrical engineers and computer scientists, who promise a push button answer to all Universe's problems. This well known answer is the number 42.  I know the early AI story personally, because in 1992-1995 (in Berkeley), we did oilfield applications using neural networks, machine learning and fuzzy computing, and published several papers. In those days, I worked with a postdoc who did his PhD thesis with the late Prof. Lotfi Zadeh, whom I knew well.  Arguably, Lotfi and his giant team were the cause of most that is occurring today in AI and machine learning.  His citation index is 275,000!

Everyone should know that The Answer to all shale problems in the US, and all other problems, is the number 42 = 61 + 62, described so well in the Hitchhiker's Guide to the Galaxy. My revolutionary counter-proposal is the number 30 = 51 + 52, the default longevity of shale wells in years. Outside of Bakken, very few horizontal shale wells will produce economically or last this long. Their expected lifespans are ~15 years, the mean of  31 + 32 = 12  and 41 + 42 = 20.  Shales have a peculiar way of deflating expectations.

Eagle Ford

15. "A Simple Physics-Based Model Predicts Oil Production from Thousands of Horizontal Wells in Shales," Tadeusz W. Patzek, Wardana Saputra, Wissem Kirati, Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, October 2017. Paper Number: SPE-187226-MS, (This elegant paper introduced the analytical physics-based scaling model of black oil production, used later by us in the Bakken papers.)


16. "Analysis of Gas Production From Hydraulically Fractured Wells in the Haynesville Shale Using Scaling Methods," Frank Male, Akand W. Islam, Tad W. Patzek, Svetlana Ikonnikova, John Browning, and Michael P. Marder, Paper presented at the SPE Unconventional Resources Conference, The Woodlands, Texas, USA, April 2014. Paper Number: SPE-168993-MS,

17. "Generalized extreme value statistics, physical scaling and forecasts of gas production in the Haynesville shale," Wardana Saputra, Wissem Kirati, and Tadeusz W. Patzek, is just out in JNGSE.  (This groundbreaking analysis of the Haynesville is a masterpiece by Wardana and Wissem.  If you want to understand the second most prolific shale play in the US, you must read this paper and its three large Supporting Online Materials files.)


18. “History Matching and Rate Forecasting in Unconventional Oil Reservoirs With an Approximate Analytical Solution to the Double-Porosity Model,” Ogunyomi, B.A., Patzek, T.W., Lake, L.W., and Kabir, C.S., SPE Reservoir Evaluation & Engineering, 19 (1), 70-82, 2015, (This is a wonderful, complex mathematical paper that provides additional insights relative to our simple (M, tau) scaling model, but at a high cost.)

19. "Physical Scaling of Oil Production Rates and Ultimate Recovery from All Horizontal Wells in the Bakken Shale," Wardana Saputra, Wissem Kirati, and Tadeusz Patzek, Energies 2020, 13(8), 2052; (The first of the two definitive papers on the past and possible futures of the Bakken shale, the largest continuous oil mudrock play in the US.)

20. "Generalized Extreme Value Statistics, Physical Scaling and Forecasts of Oil Production in the Bakken Shale," Wardana Saputra, Wissem Kirati, and Tadeusz Patzek, Energies 2019, 12(19), 3641;  (The second of the two definitive Bakken papers, even though it was published first.  Wardana spread his wings in these two papers. The 2019 paper is Energies' Editor Choice.)


21. "Study develops Fayetteville shale reserves, production forecast," John Browning, Scott W. Tinker, Svetlana Ikonnikova, Gürcan Gülen, Eric Potter, Qilong Fu, Katie Smye, Susan Horvath, Tad Patzek, Frank Male, Forrest Roberts, Oil and Gas Journal, 112(1), 64-73, Jan 6, 2014.

Permian  Basin

The crowning study of the Permian Basin will consist of two major parts, each with its large Supporting Online Materials.  The first paper will be devoted to some 550,000 vertical wells spread over many hundreds of reservoirs, and producing since the 1930s.  It turns out that about 150,000 wells were either dry holes or were plugged & abandoned for different reasons. We will make a case for more vertical wells in the future, given the new investment climate and longevity of these wells. The second part will be a study of all post-2012 horizontal wells in the Permian.  This study will make the last chapter in Wardana's PhD thesis, and it will be his Magnum Opus.


22. "Production Forecasting with Logistic Growth Models," A. J. Clark, L. W. Lake, T. W. Patzek, Paper presented at the SPE Annual Technical Conference and Exhibition, Denver, Colorado, USA, October 2011.Paper Number: SPE-144790-MS, (This paper is quite highly cited with the SPE literature)

23. "BARNETT SHALE MODEL-1: Barnett study determines full-field reserves, production forecast," John Browning, Scott W. Tinker, Svetlana Ikonnikova, Gürcan Gülen, Eric Potter, Qilong Fu, Susan Horvath, Tad Patzek, Frank Male, William Fisher, Forrest Roberts and Ken Medlock, III, OGJ, p. 62, August 5, 2013.

24. "BARNETT SHALE MODEL-2 (Conclusion): Barnett study determines full-field reserves, production forecast," John Browning, Scott W. Tinker, Svetlana Ikonnikova, Gürcan Gülen, Eric Potter, Qilong Fu, Susan Horvath, Tad Patzek, Frank Male, William Fisher, Forrest Roberts and Ken Medlock, III, OGJ, September 9, 2013.

"Factors influencing shale gas production forecasting: Empirical studies of Barnett, Fayetteville, Haynesville, and Marcellus Shale plays," Ikonnikova S., Browning J., Gülen, G., and Tinker, S., 2015, Economics of Energy & Environmental Policy, 4(1), 19-35. (Some of my work is cited in that overview paper.)

25. "Physics, fracking, fuel, and the future," Michael Marder, Tadeusz W. Patzek, and Scott Tinker, Physics Today 69(7), 46 (2016);

What remains then to do is a US shale overview paper written for PNAS,  in which Syed will also play a crucial role.  

If I sound like a proud father, that's because I am.  I have been blessed with a group of the brightest, most dedicated students and researchers anywhere, Berkeley included.  What a way for me to end my hyper-active academic career and finally retire at some time in the near future!

Other related papers

26. "Long Term Effect of Natural Fractures Closure on Gas Production from Unconventional Reservoirs," Umut Aybar, Mohammad O. Eshkalak, Kamy Sepehrnoori, and Tad Patzek, Paper presented at the SPE Eastern Regional Meeting, Charleston, WV, USA, October 2014. Paper Number: SPE-171010-MS,

27. "Evaluation of production losses from unconventional shale reservoirs,” Aybar, U., Yu, W., Eshkalak, M. O., Sepehrnoori, K., Patzek, T. W., Journal of Natural Gas Science and Engineering, 23, 509-516, 2015.

28. “Thermal shale fracturing simulation using the Cohesive Zone Method (CZM),” Saeid Enayatpour, Eric van Oort, Tad Patzek, Journal of Natural Gas Science and Engineering, 55, 476-494, 2018. (In this paper we use a sophisticated FE method to prove the rather obvious fact that because fracturing depends on all spatial scales, the CZM is also scale-dependent.)

29. “Thermal cooling to improve hydraulic fracturing efficiency and hydrocarbon production in shales,” Saeid Enayatpour, Eric van Oort, Tad Patzek, Journal of Natural Gas Science and Engineering, 62, 184-201, 2019. (This paper describes our patented process of aiding hydrofracuring of mudrocks by chemical-reaction-driven cooling.)

1. "METHOD OF IMPROVING HYDRAULIC FRACTURING BY DECREASING FORMATION TEMPERATURE," Van Oort, E. Patzek, T. W. and Enayatpour, S. US Patent No 9,920,608 B2, March 20, 2018.


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