GLC analysis of n-paraffin distributions in crude oils and topped crude oils for oil identification
Year: 1977
Type: report
Abstract: Based upon a population of 52 crude oils and 52 corresponding artificially weathered crude oil samples, weight-percent distributions of normal paraffins obtained from gas-liquid chromatographic analyses were evaluated for their importance of oil identification. By use of statistical analysis, the weight percents for the C/sub 11/ through C/sub 35/ n-paraffins were determined to be significant variables for the differentiation of unweathered crude oil samples. Similarly, the ratios of pristane to n-heptadecane, phytane to n-octadecane, and phytane to pristane were determined to be important. By use of weight-percent distributions, two numerical methods were evaluated for reducing the variations in the analytical data between weathered crude oil samples and corresponding unweathered crude oils, resulting from environmental weathering. For a population of artificially weathered and unweathered crude oil pairs, good agreement exists between the weight-percent distributions (n-C/sub 18/ through n-C/sub 30/) when the distributions are normalized to the C/sub 25/ normal paraffin. Similarly, excellent agreement is observed between odd-even predominance values (above n-C/sub 16/). Comparative analyses of both normalized n-paraffin weight-percent distributions and odd-even predominance values of a set of artificially weathered and unweathered crude oil samples from the same general geographical region, indicate that similar unweathered crude oils can be differentiated. Although the identification of a weathered sample to the corresponding unweathered crude oil is not highly reliable by either method, such comparative data, when combined with comparable data obtained from another analytical method are shown to be very important and useful. 12 tables, 21 references.
DOI: 10.2172/7213416
Authors: P.L. Grizzle, H.J. Coleman
Language: English
Subfield: Analytical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W85479215