The Compositional and Geochemical Characteristics of Continental Heavy Oils of China

Abstract

Using the solvent extraction, TLC, HPLC, GC-MS, FT-IR, UV-Visible spectrophotometry, this article analyzes the group composition, the steranes and terpanes, porphyrins, and the functional groups of asphaltene and resin components in the heavy crude oil fields of Kalamai, Ulho, Dagang, Liaohe, and Jianghan in China, and the trace metal elements in the ashes of crude of Jianghan gypsum-salt basin. 1. The asphaltene contents in heavy crude are 1 to 4 times higher than those in normal crude. The contents of saturated hydrocarbons change greatly, from 16.5% (W-30) to 64.24% (9Q-1). The quantity of saturated hydrocarbons in heavy oil is directly related to the genetic types of crude and degree of evolution. 2. The steranes and terpanes in the saturated hydrocarbons have two typical characteristics. The first is that of the Xinjiang FQ-2, in which regular ..cap alpha beta.. hopane series has been biodegraded to produce a demethyl-hopane homologous series, rich tricyclic diterpanes and regular steranes had completely degraded, but C21, C22, and C23 pregnane were obvious. The second characteristic is seen in the samples of G-753 of Liaohe and W-30 of Jianghan, in which pentacyclic triterpane was more obvious than tricyclic tetraterpane, Tm was greater than Ts, C31, C32, andmore » 22R was greater than 22S; 17a(H)21B(H)C30 hopane was the main peak. Steranes had regular forms, especially the prominent superiority of C27, C28, C29-5a, 14a, and 17a cholestane 20R, which indicated their low degree of evolution. 3. Heavy oils generally contain porphyrin compounds. Their contents and types vary with the stage of the crude's maturation.« less