Exploring the Potential of Flame Ionisation Detector Technique to Analyse Gas Tracers for CO ₂ ‐Based Enhanced Oil Recovery Applications in High‐Temperature Reservoirs

ABSTRACT Perfluorocarbon (PFC) gas tracers perfluoromethylcyclohexane (PMCH) and perfluoro‐1,3‐dimethylcyclohexane (PDCH) were evaluated for CO 2 geo‐storage and enhanced oil recovery (EOR) applications under high‐temperature conditions. A novel detection method using a flame ionisation detector (FID) was employed as a cost‐effective and environmentally safer alternative to the conventional electron capture detector (ECD), overcoming associated regulatory and maintenance challenges. Thermal stability was assessed by aging the tracers with CO 2 at 120°C for 48 h, with gas chromatography–mass spectrometry (GC–MS) confirming no degradation. Adsorption studies revealed minimal adsorption with sandstone, and energy‐dispersive x‐ray spectroscopy (EDX) indicated no significant mineralogical alterations. Wettability tests confirmed a water‐wet environment with a contact angle of ≈52°, whereas interfacial tension remained stable at ≈56.45 mN/m. The minimum miscibility pressure (MMP) of CO 2 was determined at ≈1500 psi using a slim tube apparatus. Core flooding experiments on sandstone cores from the Rajasthan oilfield, India, were conducted to evaluate tracer transport behaviour. Breakthrough curves obtained from gas chromatography–FID analysis were used to derive swept pore volume, sweep efficiency, Lorentz coefficient and tortuosity. The findings confirm the thermal and chemical stability of PMCH and PDCH tracers, validating their application in reservoir characterisation and CO 2 monitoring. The FID‐based detection approach was proven effective and practical.