Determination of Geochemical Properties and Genetic Types of Gas Condensates Using Biomarker Studies and Chemometric Analysis in Persian Gulf Basin, Iran

Comprehensive geochemical study shows the genetic relationship between 14 samples of gas condensates from the Persian Gulf. In this study, the samples were examined merely in terms of maturity, which led to a general trend towards maturation of the region. In this process, maturation increases from west to east of the Persian Gulf and also from the coastal Fars to the Persian Gulf and then to the Arabian section.
 

By using data collected including data biomarkers derived from gas chromatography-mass spectrometry analysis to provide relevant diagrams for maturity and source rock sedimentation environment, as well as statistical analysis of existing samples for all fields, which ultimately, by matching the interpretations of these two to the desired results, the purpose of this Research has been achieved.

The Samples were collected from Dalan and Kangan reservoirs (Late Permian – Triassic) from 6 gas fields (gas condensate), Which constitute the most important Iranian gas/gas condensate reservoirs. In this  study, in order to estimate the maturity of samples (for the purpose of determining the thermal maturity of gas condensates and determining their range of placement in the maturity chart), as well as determining the sedimentary environment of the source rock and type of lithology, the available biomarker parameters obtained from the results gas chromatography - mass spectrometry (GC-MS) were used. The statistical methods used are agglomerative hierarchical clustering (AHC) and principal component analysis (PCA), which show that the studied gases are in three main genetic groups.

According to the results of this study, the origin of hydrocarbons in the region of marine organic matter with some organic matter of continental origin, which maturity range is in the late stages of petroleum production and early gas window. This gas condensate is derived from the clastic lithological sources that have been generated under reducing environmental conditions and from type II and III kerogens. The three main groups of gas condensate from statistical analysis and make correlation to the source rock were identified using biomarker parameters related to maturity and sedimentation environment. The maturity from the Golshan field to the Salman field (from west to east of the Persian Gulf) increases and the sedimentary environment is different in the southern Persian Gulf Salman and Golshan fields (marine carbonate) from its northern fields such as Khayyam, Tabnak and Madar (marine shale).