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 […]
