Gas chromatographic determination of the composition of unfractionated natural hydrocarbon mixtures

Abstract

Procedures developed for determining the fractional composition of crude oils and condensates and for defining the detailed light hydrocarbon content (C 1C 9) in crude oils, stable condensates and organic matter of rocks and formation waters by multi-dimensional gas chromatography are described. Methods for the determination and prediction of logarithmic retention indices of light hydrocarbons (C 5C 9) using two stationary phases, squalane and dinonyl phthalate, are proposed. For the first time, the results of the quantitative analysis of complex natural mixtures have been used to identify their components. Possibilities are indicated for improving the detail and reliability of data by means of a combination of quantitative analytical results obtained on capillary columns with the same stationary phase at two temperatures and on the capillary columns with various stationary phases. The rocks in which the organic matter content has been investigated by pyrolysis—gas chromatography were previously powdered only, then they were placed in a reactor and heated stepwise in an inert atmosphere.