Horizontal hydraulic fracture propagation is believed to be widespread in shale plays where the frac gradient approaches the overburden – such as the Vaca Muerta, Utica, and Montney. However, horizontal propagation is nearly always ignored in hydraulic fracture modeling. In ResFrac, we are obsessed with ‘getting the physics right’, and so naturally, we extended our simulator to handle horizontal fracturing. The first version of this new capability was released earlier this year. We are eager to start collecting feedback from users, which will help us to fine tune the algorithm and workflow.

Proppant transport in the well is an intriguing topic that has attracted a lot of interest in recent years [1-8]. Proppant transport processes determine the uniformity of proppant placement, which has a direct impact on productivity. Cipolla et al. estimate that the difference between poor and excellent proppant uniformity is about $2.5M in net present value per well.

Below are links to watch two recently recorded talks. The first was a presentation with ThinkGeoEnergy discussing the impressive results from Fervo Energy’s recent Project Red pilot. The second was a presentation with whitson summarizing the URTeC-2019-123 compliance method procedure for interpreting DFITs. If you are interested in either topic, please check them out!

This blog post provides practical tips for interpreting Diagnostic Fracture Injection Tests (DFITs) using the ‘compliance method’ procedure initially developed by McClure et al. (2016) and refined in the paper URTeC-2019-123, which summarized results from a joint industry study performed with a consortium of operators.

Hydraulic fractures tend to propagate in a plane that is perpendicular to the least principal stress, as noted by Hubbert and Willis in 1957. As a result, unconventional oil and gas wells are typically drilled in the direction of Shmin to maximize drainage area. However, in some regions, due to acreage constrains by operators, wells are drilled in different directions, regardless of the stress orientation to maximize acreage production by maximizing the number of wells per acreage.

This ARMA Hydraulic Fracturing Community (HFC) presentation summarizes the work on proppant transport in horizontal perforated wellbores. Specifically, it discusses the model for proppant distribution between perforations depending on their orientation and location within the stage, optimal configurations are proposed, and performance is evaluated.

This is the most exciting time in my lifetime for geothermal. There are many, many innovative things happening. To name a few – promising new approaches to Enhanced Geothermal Systems, geothermal projects in sedimentary and lower enthalpy formations, new approaches for geothermal exploration, lithium extraction from produced brines, geothermal energy storage, integrations with CO2 storage and capture, and new technologies for producing energy from hot water that is coproduced with oil and gas. However, this post is about a concept about which I remain skeptical – deep closed-loop heat exchangers (McClure, 2021). These designs are sometimes called ‘Advanced Geothermal Systems,’ AGS (Malek et al., 2022).

Simulfrac’s are growing in popularity (see 2021 JPT article for when the trend was just gaining momentum). The idea is that one pumping crew can treat two wells simultaneously versus one well at a time. As such, a frac crew may zipper four wells at a time versus two. At ResFrac we are seeing an increase in simulfrac interest across our consulting and license customers. Simulfrac’ing wells within the ResFrac software is simple to set up without any complicated modifications – so this makes ResFrac an ideal platform to investigate the effects of simulfracs.

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).

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).

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.

In this blog post, we review a refracturing and economic optimization case study. The model and history match are loosely based on “SPE Data Repository Well #1,” a publicly available refracturing and production dataset from the Eagle Ford shale. This post extends the analysis that we presented at a recent SPE workshop, “What New for PTA and RTA”.

Field scale hydraulic fracture simulations reveal a variety of complex fracture geometries. Very often stress interaction between the fractures leads to very asymmetric fracture growth within a stage. At the same time, for some other cases, all the fractures are more regularly shaped and symmetric. This blog post presents results of numerical simulations and analysis demonstrating how fracture morphology changes versus problem parameters for some fundamental cases. The results can be used to better understand the observed fracture complexity in a field scale simulation or as a guideline to achieve the desired fracture morphology.

There has been a lot of controversy over the past five years over how to estimate stress/closure pressure from shut-in pressure transients from Diagnostic Fracture

Should we use ‘planar fracture’ models or ‘complex fracture network’ models? Exciting new field data has been published by operators that helps us answer this question,

This post grapples with a complicated, nuanced, and important topic: what do hydraulic fractures look like and how should we model them? Should we use

Rate Transient Analysis (RTA) is commonly used to analyze production in unconventional reservoirs. The concept of RTA is to use rate signatures of producing wells to estimate properties such as permeability and fracture surface area. For more detailed analysis, fracture simulators, reservoir simulators, and coupled fracture/reservoir simulators, like ResFrac, can be used.

Typically, hydraulic fracture simulations predict symmetrical propagation away from the wellbore. For example, the figure below shows a ResFrac simulation of fracturing and production in

Multistage hydraulic fracturing in horizontal wells enables economic production from low permeability resources. A variety of parameters needs to be optimized: stage spacing, cluster spacing,

In this post, I discuss an important new paper, “Sampling a Stimulated Rock Volume: An Eagle Ford Example,” by Raterman et al., which was presented at URTeC in July. This paper is an instant classic (kind of like Game 5 of the World Series last Sunday!).

Introduction Back in February, I was at an SPE DFIT workshop where David Craig (one of the vocal advocates of the ‘holistic’ method of picking

In this post, I address a topic that seems esoteric, but it has critical implications for understanding how DFITs respond to closure. In turn, this directly affects how we estimate stress and permeability. The question under investigation: do fractures store and conduct fluid after they close? My answer: in most DFITs, yes. Two caveats: unless the formation is extremely soft or ductile (allowing residual aperture to be nearly zero) or the matrix permeability is sufficiently high (making the residual fracture conductivity so small relative to the matrix permeability that it is negligible). Note that as fluid pressure draws down after mechanical closure, conductivity decreases. So it is possible that fractures that are hydraulically conductive during a DFIT may effectively close when fluid pressure is drawn down during long-term production (this depends on the stiffness and strength of the asperities that allow the mechanically “closed” fracture to retain aperture).