Postclosure DFIT interpretation: Demystifying the Linear Flow Time Function
![the pressure perturbation during shut-in from a ResFrac DFIT simulation](https://www.resfrac.com/wp-content/uploads/2019/07/da1386_d5aa62ff424d48d4bd8e1a9a4749a323mv2-1024x460.png)
“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 plot of a typical DFIT.](https://www.resfrac.com/wp-content/uploads/2019/07/da1386_57969f364a7c41c28d79ee4b1315dce8mv2.png)
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.
Diagnostic Fracture Injection Tests: The Basics
![A typical pressure response during injection in a DFIT.](https://www.resfrac.com/wp-content/uploads/2019/07/da1386_170d655ae1d84d2c98e82c1a8bf3316fmv2.png)
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 […]