Commentary on Four New DFIT Papers: (a) Direct In-Situ Measurements of Fracture Opening/Closing from the EGS Collab Project; (b) Comparison of Stress Measurement Techniques from the Bedretto Project; (c) a Statistical Summary of 62 DFITs Interpretations Across Nine Shale Plays; and (d) A Different Perspective: An Article Advocating the Use of the Tangent Method

This post provides commentary on recent four papers on diagnostic fracture injection testing (DFIT). The first paper uses in-situ deformation measurements to directly observe fractures opening and closing during fracture injection-falloff tests (Guglielmi et al., 2022). The second compares various stress measurement techniques in a series of fracture/injection tests from the Bedretto project (Bröker and Ma, 2022). The third statistically reviews results from applying the interpretation procedure from McClure et al. (2019) to 62 DFITs across nine different shale plays (McClure et al., 2022). The fourth is an op-ed written in JPT (Journal of Petroleum Technology) by an advocate of the tangent method for estimating DFIT closure stress (Buijs, 2021; 2022). This article presupposes that the reader already has familiarity with these topics. If you would like more background, please refer to McClure et al. (2019).

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Notable Papers from SPE HFTC 2022

The SPE Hydraulic Fracturing Technology Conference (HFTC) was last week. There were tons of great, practically relevant, papers. People are really locked-in on the key value drivers. This blog post gives a sampling of a few of the papers that I found most interesting. I don’t discuss any of the ResFrac papers because they were in a previous blog post.

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Epistemic Challenges for Subsurface Engineering, Part II: Creating Value with a Hypothesis-Driven Workflow

How can we reconsider our approach to subsurface engineering in order to evaluate claims of truth and drive long-term value? I propose a hypothesis-driven approach, in which field testing is placed at the center of our efforts to assess the truth and improve over time. Physics-based and data-driven approaches are used as hypothesis-generating activities that motivate and prioritize hypothesis testing through field operations. Effective field testing requires the coordination of operations to enable clean well-to-well production comparisons and the design of data collection to enable strongly supported conclusions. Field testing need not increase the cost of field operations if it is done through intentional and thoughtful planning.

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Epistemic Challenges for Subsurface Engineering, Part I: The Persistence of False Beliefs

In a recent blog post, I outlined how companies use field tests, modeling, statistical analysis, and laboratory studies to improve over time. Information is synthesized as part of an iterative process of continuous improvement. In this post, I discuss what happens when the process of continuous improvement runs into trouble. In uncertain environments (like subsurface shale), there is a tendency toward overconfidence. We need to act, and in doing so convince ourselves that we are making the right decision. Sometimes we hire experts who ‘confidently confirm’ our beliefs. This is symptomatic of a phenomenon called confirmation bias, where we tend to ignore new data and outcomes that contradict our initial beliefs. After committing to strong claims, we may have difficulty changing course when it becomes apparent that they are not consistent with observations. This can cause false beliefs to persist for years, long after they have been falsified by field data.

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