Application of light hydrocarbons for classification and geochemistry characterization of condensates from the Gavbendi High, southwest Iran

Abstract

Light hydrocarbons are beneficial compounds to achieve geochemical information from condensates. Due to lower concentrations of biomarkers in condensates, the limited applicability of these compounds can be compensated by light hydrocarbons in the geochemical studies. For the first time, the condensates of Iranian gas condensate fields in Gavbendi High were studied by light hydrocarbons in this paper. Twenty condensates from 8 different gas condensate fields were collected to investigate the genetic families and their distributions in the regional uplift of the Fars platform. Applying different light hydrocarbon parameters revealed two distinct genetic families in the studied area. Group I includes SNL, HMA, TBK, and VAR fields located in the eastern parts of the High, and group II consists of AGH, DL, KGN, and NR fields in the western parts. The stable carbon isotope data also confirmed the defined genetic families. The effect of secondary processes on the samples was very slight, and the samples experienced a lower level of biodegradation with water washing. The light hydrocarbons showed that the terrestrial organic matter has a higher contribution to the generation of group I samples, and group II samples have a higher contribution from the marine organic matter. Also, the source of group I samples was clay-rich, and the source rock of group II samples was clay-poor. The group I samples sourced from the Sarchahan Shaly Formation show higher clay contribution than the group II samples that originated from the mixture of the Sarchahan and upper Kangan source rock layers. The thermal maturity assessment indicated that the group II samples have higher maturity, and the northern fields in both groups have lower maturity than the southern fields. The maturity trend implies that the source rock layers of group II have been buried deeper than the group I source rock. Both groups were charged laterally from the surrounding withdrawal synclines source kitchens located in the southern area on both sides of the Gavbendi High.