88 Energy Ltd (EEENF)

[PENNIEStoSTACKS]

Fluorescence can be an extremely sensitive indicator of the presence of hydrocarbons in drill cuttings. Sample fluorescence is evaluated in terms of color (ranging from brown to green, gold, blue, yellow or white), intensity and distribution. Fluorescence color may indicate oil gravity; dark colors are suggestive of low API gravity heavy oils, and light colors indicate high API gravity light oils. Following application of a solvent on the samples, hydrocarbon fluorescence will appear to flow and diffuse into the solvent as the oil dissolves. This diffusion is known as cut fluorescence, or more commonly just cut. Under UV light, hydrocarbons may be seen to stream from the rock pores into the surrounding solvent, turning the solvent cloudy.

To measure gas, the mud logger relies on an automated gas detection system. Suction lines transport a constant stream of air and gas from the gas trap, located at the shale shaker, to the logging unit. There, sensitive instruments process the gas samples extracted from the drilling mud. The primary gas measurement tool is a flame ionization detector (FID), which can sense hydrocarbon gas concentrations as low as 5 parts per million. From FID measurements, a total gas curve can be plotted on the mud log. Background gas—a more or less constant, minimum level of gas—establishes a baseline on the total gas plot. A gas show is any significant increase in detected gas, which is usually associated with a zone of increased porosity or permeability.
https://www.slb.com/resource-library/oilfield-review/defining-series/defining-mud-logging