DAS Distributed Acoustic Sensor. Involves the deployment of fiber optic cable on the surface or in a well, and the detection of small variations in the refractive index of the fiber based...

DFIT Diagnostic Fracture Injection Test. A subsurface well test in which pressure is monitored as a small volume of fluid is injected into a reservoir to develop a hydraulic fracture....

Diorite Dark colored, coarse grained, intrusive rock that contains less silica than granite and that is mostly made of plagioclase, biotite, hornblende, pyroxene, and minor to nil quartz.