Skip to main content

Update on US shale play papers by Patzek et al.

 This is a continuation of the previous list of 29 papers and 1 patent:

30. Zhu, W., Khirevich, S., & Patzek, T. W. (2021). Impact of fracture geometry and topology on the connectivity and flow properties of stochastic fracture networks. Water Resources Research, 57, e2020WR028652. https://doi.org/10.1029/2020WR028652

Natural fractures usually comprise complex networks and control many physical properties of rocks, including stiffness, strength, and permeability. Therefore, they significantly impact many engineering fields, such as hydrology, waste disposal, geothermal exploitation, and petroleum reservoir exploitation. In a low permeability formation, fractures play a dominant role because the contribution of the matrix to fluid flow is almost negligible. Connectivity of natural and induced fractures thus determines the overall capability of fluid flow of subsurface rocks. Commonly used approaches to evaluate the connectivity (percolation method, connectivity index/field, and intersection index) are insufficient to capture the impacts of all geometrical properties of arbitrary fracture networks. Therefore, we utilize a topological concept of global efficiency to investigate the key geometrical properties of two-dimensional (2D)/three-dimensional (3D) stochastic fracture networks quantitively. After analyzing thousands of realizations of stochastic fracture networks, our results show that geometrical properties, including fracture lengths, apertures and positions of fracture centers, influence the connectivity of fracture networks. Aperture variations cause a significant change in connectivity of a fracture network, especially for fracture networks dominated by large fractures. Clustered and small fractures usually lower global efficiency in both 2D and 3D fracture networks. Similar conclusions are valid in realistic fracture networks composed of several sets of fractures with constrained preferred orientations.

(a) A fracture system at Ras Al Khaimah in the United Arab Emirates; (b) Realistic 2D fracture networks with four fracture sets; (c) Realistic 3D fracture networks with four fracture sets.

31. Wardana Saputra, Wissem Kirati and Tadeusz W. Patzek, "Generalized extreme value statistics, physical scaling and forecasts of gas production in the Haynesville Shale," Journal of Natural Gas Science and Engineering, 2021, 104041, ISSN 1875-5100, https://doi.org/10.1016/j.jngse.2021.104041.

We present a hybrid, data-driven and physics-based method of forecasting play-wide gas production in the Haynesville Shale, which is currently the second-largest shale gas producer in the US. We first define several statistical well cohorts, one for each reservoir quality and each well completion technology in the Haynesville. For each cohort, we use the Generalized Extreme Value (GEV) statistics to obtain the historical average well prototypes. The cumulative production of each well prototype is matched with a physics-based scaling curve, and its production is then extrapolated for up to two more decades. The resulting well prototypes are exceptionally robust. If we replace individual production rates from all existing wells with their corresponding well prototypes and sum them up, the total rate will match remarkably the past gas field rate, and – in this case – we obtain a base or do nothing forecast. Next, we calculate the number of potential infill wells per square mile and schedule future drilling programs to obtain plausible production forecasts in the Haynesville. Because Haynesville is the most active shale play in North America in terms of refracturing, we also propose a novel approach to identify refracturing candidates among the old Haynesville wells and deliver another forecast scenario of future refracs. We predict that Haynesville will ultimately produce 30 Tscf of natural gas from the 4684 existing wells. Most likely, by drilling 923 new wells in the core (sweet spot) areas by 2023, EUR will increase to 40 Tscf. Additional 5023 wells in the noncore areas are forecasted to be drilled by 2032, increasing EUR to 90 Tscf. We also show that refracturing old Haynesville wells is more cost-effective than drilling new wells in the poor quality reservoir, especially in the era of low oil and gas prices.




Comments

Popular posts from this blog

Ascent of the Angry and Stupid

Scientifically speaking,  stupid  people harm themselves while also harming others. In addition, stupid people are irrational and erratic, and are very dangerous to others. After discussing the destructive role of the stupid in any society whatsoever, I will focus on the delicate interplay of actions of intelligent and helpless people, who in balance make or break a functioning democracy.  Unless things change fast in the US, we can kiss our democracy goodbye for decades. If you want to see how a virulent ascent of the stupid looks up close, and what implications it has for our fight against social injustice and climate change, please watch the brilliant " Don't Look Up " movie. Unvaccinated people demonstrating in Los Angeles. There are tens of millions of the raving mad and/or angry, stupid people in the US and other developed countries. Source: New York Times , 12/25/2021. I overlapped at UC Berkeley with Professor Carlo M. Cipolla for a decade, until his death in t

Confessions of a Petroleum Engineer and Ecologist

I just attended an SPE workshop, "Oil and Gas Technology for a Net-Zero World – Defining Our Grand Challenges for the Next Decade."  Of the 60 people in the audience, I knew 1/3, some very well.  It makes sense, because I have been an SPE member for 40 years, and a Distinguished Member for 20 years.  Last year, I received an SPE EOR/IOR Pioneer Award for my work at Shell and UC Berkeley on the thermal enhanced oil recovery processes that involved foams, and their upscaling to field operations. This was nice, because Shell recognized me as one of their best reservoir engineers, and in 1985 I received an internal Shell Recognition Award for the same work. But I am not a mere oil & gas reservoir engineer.  First and foremost, I am a chemical engineer and physicist, who has thought rigorously about the sustainability of human civilization , ecology and thermodynamics of industrial agriculture and large biofuel systems, as well as about the overall gross and net primary produc

Net Ecosystem Productivity is Zero on Planet Earth

In the last bog , I told you how the law of mass conservation governs the large-scale behavior of Earth's households - ecosystems - that must recycle all mass on average and export only low quality heat into the cold universe.  Now, I will give you a few useful definitions of cyclic processes, sustainability, and ecosystem productivity. Let me start from stating the obvious:  We live in a spaceship we cannot leave, a gorgeous blue, white and green planet Earth that takes us for a spin around her star, the Sun, each year. But this statement is imprecise. We really live on a vanishingly thin skin of the Earth, her ecosphere .   Think of this skin as of a thin delicate membrane, teaming with life and beauty, but incredibly fragile. We trample on this membrane and poison it.  Then we act surprised when it brakes and shrivels. Practically all life on the Earth exists between two concentric spheres defined by the mean Earth surface at the radial distance from the Earth's