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Optimization of perforation orientation for achieving uniform proppant distribution between clusters
Previously, a mathematical model for the problem of slurry flow in a perforated wellbore was described and the underlying physical mechanisms were discussed. The purpose of this blog post, on the other hand, is to couple the model with an optimization algorithm to investigate optimal perforation orientations that lead to the desired uniform proppant distribution between perforations. A brief description of the model is added at the beginning to cater for readers who are not familiar with the previous blog post.
Interesting papers from the 2023 SPE Hydraulic Fracturing Technology Conference
The 2023 SPE Hydraulic Fracturing Technology Conference was last week, and as usual, it had an outstanding lineup of papers and speakers. This blog post has a brief lineup of some of the papers that I found most interesting. As in past years, this rundown focuses on papers that I found interesting, based on my own personal interests. Usually, I am most interested in papers that improve our understanding ‘what’s going on’ in the subsurface. Also, I coauthored a paper at the conference, so naturally, I can’t help but include it on this list!
Proppant distribution between perforation clusters
This blog post summarizes the model for calculating proppant distribution between perforation clusters. A very detailed description of the model and literature review are available in [1]. The purpose here is to outline the model and its main features, to demonstrate the comparison with some of the available data (more comparisons in [1]), as well as to discuss limiting cases and sensitivities to various parameters. This blog post is solely focused on presenting the mathematical model. In future work, the results will be applied to practical optimization decisions.
Simulating ‘Fractal Fracture Swarms’ in a General-Purpose Reservoir Simulator
This blog post describes a new capability in ResFrac to capture the effect of ‘fracture swarms’ on production decline trends. Based on work from Acuna (2020), the idea is that variable spacing between fractures causes a gradual onset of production interference. Fractures in a swarm may be numerous and tightly spaced, so rather than representing each individual crack in the model, we treat each swarm as a single crack and use a numerical technique to capture their effects. In ResFrac, this capability is useful because it provides another mechanism for explaining (and matching) production drawdown trends. For further details, refer to Section 19.10 from McClure et al. (2022).
How to Diagnose False Radial Flow in a Diagnostic Fracture Injection Test (DFIT)
Genuine radial flow is rare in shale DFITs. If it does occur, it is typically observed in tests with very low injection volume (less than 10-20 bbl), unusually long shut-in (longer than one week), and relatively high permeability (greater than one microdarcy). Genuine radial flow should only be diagnosed if it occurs after an extended (at least one log cycle) period of after-closure linear flow. If ‘false radial’ flow is misdiagnosed and used to estimate permeability, it leads to a large overestimate (10-100x).
Reflections from the 2022 Geothermal Rising Conference
This is an exciting time for EGS. Multistage hydraulic fracturing has tremendous potential to improve the productivity of geothermal wells in low permeability formations. Projects are happening right now to test this concept in full-scale EGS wells. If they prove successful, we could soon see a major increase in geothermal energy production.
Automated history matching to fracture geometries as measured by Volume to First Response (VFR): A Tutorial
In this post, I will walk through a simple example of using SWPM to calibrate the fracture geometries of a hypothetical data set leveraging the ResFrac Automated History Matching functionality to expedite the workflow. In a follow-on post, I use the model to demonstrate some intuitions on fracture geometry using the Sensitivity Analysis functionality as well as some nuances of VFR calibration.
