Approach to Evaluate the Probability to Encounter High Amounts of Non-Hydrocarbons in Reservoirs: Dutch CO2 Case Studies

Non-hydrocarbons (H2S, CO2, N2) reduce the economic value of natural gas accumulations. This paper presents new approaches to evaluate the probability to encounter high amounts of non-hydrocarbons. These approaches were developed as one of the deliverables of a 2-year JIP project carried out by TNO from September 2014-July 2016. The newly compiled quality-coded database of geochemical and stable isotopic compositions of natural gas accumulations in the onshore and offshore Netherlands, the visualization of these data in maps and the analysis and interpretation of the identified spatial distribution of the geochemical and isotopic composition of the gas provided improved process-based insight into the spatial distribution of the non-hydrocarbons in relation to its geological setting. This insight allowed the identification of factors to evaluate the probability of encountering high amounts of non-hydrocarbons. The development and application of the approach is illustrated for case study examples of CO2-rich gases in the Netherlands onshore and offshore.