Predicting the Distribution and Concentration of H2S in Eastern Central Luconia

The distribution of the H2S in sour gas carbonate fields in eastern Central Luconia is geographically influenced, where fields near the deep-rooted WBL generally have higher concentration of H2S likely due to their proximity of accessing the thermal fluid migration with TSR via the WBL fault system. The efficiency of the H2S-generating process relies on the proximity of the sour gas carbonate fields to the source of H2S (sulphate), the energy source and the timing of migration of the H2S into the gas reservoir. It is observed that carbonate fields with a small Hhc/Hstrc ratio have lower concentration of H2S; as opposed to the ones with high Hhc/Hstrc that exhibits higher concentration of H2S levels. This is attributed to the water-scrubbing process of removing the H2S from the sour gas that occurs naturally due to the existence of a large water column beneath the GWC. These observations are used to ascertain the maximum possible H2S concentration of the on-going B14 development; therefore, minimising the potential project and commercial risk of the project. The same observations and learnings can be transferred into the uncertainty assessment of the presence of H2S and estimation of its concentration in future exploration and appraisal wells.