Isotopic Analysis Solution

July 22nd, 2019

Gas isotopes are a flexible tool, adding value in any phase of the upstream activity. For many years natural gas was primarily characterized simply by its chemical composition, the dry gas definition being a clear example of this. In the early 1980’s, the isotopic characterization of gas was extensively introduced, mainly to distinguish between a thermogenic or biogenic origin of the gas.

The increasing availability of isotopic gas composition data has revealed the ability to provide many additional key pieces of information, including gas maturity, gas provenance, migration patterns, the presence of common or differing sources for gas and oil coexisting within the same reservoir, cap rock efficiency, reservoir continuity, well integrity and many others. Isotopes have also been used for geosteering in unconventional reservoirs, maintaining the wellbore within the most prolific organic facies. Today, the big and bulky mass spectrometers previously used in labs can be replaced by small and more robust equipment based on laser spectrometry.

GEOLOG offers a comprehensive range of carbon isotopic analyses at the wellsite by use of a patented analytical solution. The technology uses equipment based on laser spectrometry to bring isotopic analysis to the wellsite, with the capability to provide isotopic analysis of methane, ethane, and propane while drilling. This ability to perform a multicomponent analysis in real time combined with flexible sampling intervals, all backed by laboratory-quality levels of accuracy, provides a significant advantage to the operator. This service allows the development not only of a high degree of competency in data acquisition but also in the interpretation of the data gathered.

The figure below shows an example of a simple carbon isotope application: two gases in the same reservoir have different chemical composition; the Chung plot, obtained by using isotopic data, highlights that both gases have the same origin and characteristics, but that gas B has been contaminated by the presence of biogenic gas, probably trapped when reservoir was at a shallower depth. For more information, visit www.geolog.com