The SPE Hydraulic Fracturing Technology Conference (HFTC) is this week. As usual, it looks to have an excellent lineup of papers. Next week, I’ll write a blog post reviewing some of my favorites.

We at ResFrac are coauthoring four papers at HFTC. The papers describe: (1) a parent/child case study performed with Devon in the SCOOP/STACK (Ratcliff et al., 2022), (2) our new automated history matching and economic optimization tools (Kang et al., 2022), (3) a new crack propagation algorithm designed to improve numerical accuracy and handling of thin layers (Dontsov et al,. 2022), and (4) a modeling study on application of multistage hydraulic fracturing for geothermal energy extraction (McClure et al., 2022). If you will be at HFTC, please check them out!

The parent/child case study demonstrates the ‘frac hit damage mechanisms’ that we implemented in the code last year (McClure, 2020). During frac hits, chemical processes can cause loss of fracture conductivity, impacting production in both the parent and child wells (Rassenfoss, 2020; Jacobs, 2021; Lantz, 2022). We show how these processes can be represented in a numerical simulator and used to history match field-scale data. The paper’s history match includes high-quality diagnostics such as offset fiber and sealed-wellbore pressure monitoring. With a fully calibrated model, we have the ability to optimize operations around parent/child challenges by performing high-fidelity ‘digital twin’ simulations of alternative development scenarios.

Our history matching paper demonstrates the application of our new automated history matching algorithm. The algorithm takes advantage of ResFrac’s deployment on the cloud, which makes it easy to spin up dozens of simulations to run simultaneously. We’ve combined these capabilities with an inverse modeling algorithm, which outputs not only a ‘best fit’ simulation, but also an assessment of uncertainty and/or nonuniquness. The history matching/optimization capability is deeply integrated with our user-interface, making it easy to set up optimization runs and to postprocess the results.

The crack propagation algorithm paper demonstrates a remarkable numerical algorithm developed by our Chief Scientist, Egor Dontsov. Typically, in a fracturing simulator, crack propagation is handled by either adding ‘one element at a time’ or by constantly remeshing as the crack grows. The former can be affected by mesh-related effects such as thin layers, and the latter is computationally intensive. Egor’s algorithm uses the ‘add one element at a time’ paradigm, with a twist. When a new crack element is created, it is not assumed to be ‘fully formed.’ The position of the crack front is tracked within each element. This gives the method much greater resolution than the actual ‘element size.’ Egor has performed detailed derivations and numerical testing to implement this concept in a way that has high numerical accuracy, even with a relative coarse mesh.

The geothermal paper explores a topic that has recently received a lot of attention – the use of multistage hydraulic fracturing to dramatically increase the productivity of geothermal wells. ResFrac is very well-suited to model these systems because it couples reservoir processes such as heat conduction and thermoelastic stress change with fracture mechanics.

In multistage fracturing, zonal isolation and limited-entry completion naturally create a huge number of flowing fracture pathways. This could be a huge boon for geothermal and lead to much greater energy production per well (McClure, 2021). However, positive feedback loops from thermal stress changes shorten system lifetime and impact economics. In the paper, we demonstrate how these processes can be simulated and optimized to maximize return on investment.

References

Dontsov, Egor, et al. 2022. “A New Crack Propagation Algorithm That Enables Accurate Simulation of Propagation Across Thin Layers in a Practical Field-Scale Fracturing Model.” Paper presented at the SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, USA, February 2022.  https://doi.org/10.2118/209146-MSSPE 209146

Jacobs, Trent. 2021. “What Is Really Happening When Parent and Child Wells Interact?” Journal of Petroleum Technology. https://jpt.spe.org/what-is-really-happening-when-parent-and-child-wells-interact

Kang, Charles A., McClure, Mark W., Reddy, Somasekhar, Naidenova, Mariyana, and Zdravko Tyankov. 2022. “Optimizing Shale Economics with an Integrated Hydraulic Fracturing and Reservoir Simulator and a Bayesian Automated History Matching and Optimization Algorithm.” Paper presented at the SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, USA, February 2022.  https://doi.org/10.2118/209169-MS

Lantz, Michael. 2022.  Patent-Pending Rigless Chemical Process Enhances Oil and Gas Production in Eagle Ford.  Journal of Petroleum Technology. https://jpt.spe.org/patent-pending-rigless-chemical-process-enhances-oil-and-gas-production-in-eagle-ford.

McClure, Mark. 2020. Modeling Frac Hit Damage in ResFrac. ResFrac blog. https://resfrac.com/blog/modeling-frac-hit-damage-resfrac

McClure, Mark. 2021. Why Multistage Stimulation Could Transform the Geothermal Industry. Journal of Petroleum Technology. https://jpt.spe.org/why-multistage-stimulation-could-transform-the-geothermal-industry

McClure, Mark, Kang, Charles, and Garrett Fowler. 2022. “Optimization and Design of Next-Generation Geothermal Systems Created by Multistage Hydraulic Fracturing.” Paper presented at the SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, USA, February 2022. doi: https://doi.org/10.2118/209186-MS

Rassenfoss, Stephen. 2020. Solving Gummy Bears Mystery May Unlock Greater Shale Production. Journal of Petroleum Technology. https://jpt.spe.org/solving-gummy-bears-mystery-may-unlock-greater-shale-production

Ratcliff, Dave, McClure, Mark, Fowler, Garrett, Elliot, Brendan, and Austin Qualls. “Modelling of Parent Child Well Interactions.” Paper presented at the SPE Hydraulic Fracturing Technology Conference and Exhibition, The Woodlands, Texas, USA, February 2022. doi: https://doi.org/10.2118/209152-MS