Reservoir and Source Rock Evaluation Services

• To identify the biogenic, mixed or thermogenic origin of gas
• To establish the provenance of gas in cap rocks and to assess seal efficiency
• To determine maturity of gas evaluation
• To identify possible sources of gas
• To assess compatibility between gas and associated oil (similar source or maturity?)
• To detect and quantify possible mixing of gases with different origins
• To corroborate fluid contact identification
• To corroborate reservoir connectivity

Chemical analyses of gas compositions are fundamental, but sometimes these data are insufficient to fully understand gas origin, maturity and distribution.

For example, a well-sealed thermogenic gas reservoir underlying less mature or biogenic gas sourcing shales would be isotopically heavier than the gases in the overlying cap rocks. In the event the seal was leaking, the overlying gases would develop a heavier isotopic signature due to the presence of the thermogenic gases entering the seal. By recognizing these trends operators can gain a better understanding of the gas origin, being indigenous or migrated from a reservoir, through slight but continuous leakages.

To understand the origin of gas, GEOLOG utilises various published models validated by case histories and based on integration of compositional and isotopic values.

In exploration, the GeoIsotopes service can be utilized to understand the origins of oil, to identify source rocks and help confirm migration pathways.