Comparative Analysis of the Hydrocarbon Composition and Technological Characteristics of Gas from Fields in the Ustyurt Region

Previous studies of natural gas from the Ustyurt region have focused mainly on geological characteristics or individual quality parameters, whereas integrated assessments linking hydrocarbon composition, energy performance, impurity concentrations, and flow-rate-based treatment loads at individual gas gathering stations (GGSs) remain limited. This study addressed this gap by comparing 15 sets of production and analytical data from GGSs at fields in the Ustyurt region. Seven gas streams were examined in detail using direct comparison, range analysis, and calculations of daily mercury and volumetric hydrogen sulfide loads. The principal contribution of the study is the combined assessment of gas composition, energy properties, and impurity loads under field operating conditions. Increasing C 2 + hydrocarbon content was associated with higher gas density, molar mass, higher heating value, and Wobbe index. For the seven selected sites, linear relationships were obtained between C 2 + content and both higher heating value (R 2 = 0.9938) and Wobbe index (R 2 = 0.9893). The gas with the highest methane content did not exhibit the highest energy value because of its low CS 2 + content and comparatively high carbon dioxide concentration. The stream with the highest mercury concentration was not the stream with the greatest daily mercury load, demonstrating that impurity concentration must be evaluated together with gas flow rate. The results provide a basis for GGS-specific decisions on mercury and hydrogen sulfide removal, hydrocarbon dew-point control, stream blending, and feed preparation before transportation and downstream gas processing.