What’s New: HFTC, the Parent/Child Industry Study, HFTS2, Supercritical Geothermal, DFIT, and Automated History Matching

This post reviews some of the more interesting things happening at ResFrac right now: HFTC paper with Apache on Calibrating models with offset fiber, parent/child well industry study, HFTS2 project, engineering geothermal systems, DFIT’s and automated history matching.

Integrated Reservoir Modeling Supports a Culture of Continuous Improvement

The ResFrac mission is to accelerate the process of continuous improvement. We simulate the entire well lifecycle in a single integrated simulation, help operators to synthesize information, make changes, and continue to improve.

Theoretical and Empirical Problems with the Holistic Permeability Correlation for DFIT Interpretation

In this post, I focus on a particular correlation that is sometimes used in the industry to estimate permeability from a shale DFIT: the ‘holistic permeability correlation.’ I show that this correlation can greatly overestimate permeability. When applied to optimize frac design, well spacing, and cluster spacing, overestimated permeability leads to significant loss of economic value.

Best Practices in Interpretation of DFIT Tests for Shmin, Permeability, and Pore Pressure

DFIT interpretation has been a theme of the work that we’ve done within ResFrac. Our collaborative 2018 Industry Study, which culminated in one of the ‘Best of URTeC’ papers in […]

Postclosure DFIT interpretation: Demystifying the Linear Flow Time Function

“Postclosure” interpretation is used to infer formation permeability from DFIT pressure measurements. As reviewed in previous posts, the goal of a DFIT is to infer formation properties, of which permeability […]

Curving G-function plots and picking closure

G-function plots are routinely used to interpret diagnostic fracture injection test (DFIT) transients. Ideally, a plot of pressure versus G and G*dP/dG versus G should form a straight line. However, the G*dP/dG curve is very often curving. A typical DFIT transient is shown below.

Demystifying the G-function

Diagnostic fracture injection tests (DFITs) are commonly interpreted by plotting pressure versus a function of time called the G-function. The G-function seems rather arcane and is often misunderstood. However, it has […]

How to plot a DFIT

Aside from the diversity of terminology, the diversity of plotting techniques is the aspect of DFIT analysis that most often causes confusion. Why don’t we just make a Cartesian plot of pressure […]

DFIT, LOT, XLOT, Minifrac, Microfrac, Fracture Calibration Test: Navigating the Terminology

A bewildering variety of terms are used to describe tests in which a small volume of fluid is injected to create a hydraulic fracture: DFIT, leakoff test (LOT), extended leakoff […]

Diagnostic Fracture Injection Tests: The Basics

In a diagnostic fracture injection test (DFIT), a relatively small volume of fluid is injected into the subsurface, creating a hydraulic fracture. After the end of injection, the pressure in […]