Home – Home – Jornals – Chemistry for Sustainable Development 2019 number 2

This paper presents the results of the studies of cyclic aromatic compounds composition in gas condensates of Maloyamalskoye and Myldzhinskoye gas fields of Western Siberia. The composition of aromatic compounds in gasoline cuts of gas condensates was analyzed by GC method. Data on group composition of С7–С10 aromatic compounds in gasoline cuts demonstrate that the gas condensates of Maloyamal’skoye gas field are enriched with toluene (С7) and xylenes (С8) while in the samples of Myl’dzhinskoye gas field the contents of trimethyl- (С9) and tetramethyl benzenes (С10) are high. The composition of aromatic compounds of benzene, naphthalene and phenanthrene series in the non-fractionated condensates was studied using GCMS method. It has been shown that alkyl benzenes of condensates are represented predominately by low-molecular compounds (С7–С10), content of long-chain n-alkylbenzenes and n-alkyltoluenes is very low. In addition to alkyl-substituted benzenes the naphthene-substituted benzenes (methyl- and dimethyltetralines) are identified in gas condensates. The relative concentrations of cadalene, retene, ethyl benzene, 1,2,3- and 1,2,4-trimethylbenzenes are used as genetic factors on the composition of aromatic compounds. It has been established that humic organic matter contributed to the formation of the studied fluids. The evidences of that are: higher than usual values of Prystane/Phytane ratio; high content of xylene; increased content of 1,2,5- and 1,2,7-trimethylnaphthalenes and the presence of aromatic hydrocarbons – biomarkers (cadalene, retene). Parameters calculated from the composition of alkyl benzenes and alkyl naphthalenes determine the thermal maturity of condensates. According to the values of ratio (m- + p-xylene)/o-xylene, naphthalenic indexes (MNR, DNR2 and TNR6) and low content of long-chain С11+ alkyl benzenes the catagenic maturity level of the studied fluids corresponds to the main gas generation phase.