The Compositional and Geochemical Characteristics of Continental Heavy Oils of China
Titel:
The Compositional and Geochemical Characteristics of Continental Heavy Oils of China
Auteur:
Zhiqiong, Yang Xinzhang, Gu Ling, Zhang
Verschenen in:
Energy sources. Part A, Recovery utilization and environmental effects
Paginering:
Jaargang 9 (1987) nr. 4 pagina's 211-227
Jaar:
1987
Inhoud:
Using the solvent extraction, TLC, HPLC, GC-MS, FT-IR, UV-Vis-ible spectrophotometry, this article analyzes the group composition, the ster-anes 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. From the analyzed results, the following can be concluded: 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 aβ 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, and 22R was greater than 22S; l7a(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 cho-lestane 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. Liquid chromatogram of free-base porphyrin of crude oil in Kalamai, Ulho, showed D31 was greater than D32, with a D32 :D31 ratio of 0.39; for the Bohai Bay crude showed D32 was greater than D31, with a D32:D31 ratio of 1.38; and for the gypsum-salt region of Jianghan basin showed D32 was nearly equal to D31, with a D32:31 ratio of 1.02. 4. The infrared spectra of the resin in heavy oils revealed three types: (I) The heavy oil of Xinjiang district was rich in oxygen-bearing compound. The maximum absorption of carbonyl C=0 in infrared spectrum of resin lies at 1730cm-1', and conjugation bond of ether with carbonyl gave a series of strong absorptions at 1275 cm-1 1120 cm-1 1070 cm' -1, etc. (2) The maximum absorption of carbonyl C=0 in infrared spectrum of resin in the heavy oils of Shengli and Dagang oilfields was situated at 1690 cm' -1. (3) The C=0 maximum absorption as stated above in the gypsum-salt basin lies at 1650 cm-1. 5. The ashes of Jianghan heavy oils contained more than 13 trace metallic elements, in which the contents of other elements, except Ca, Mg, and Pb, were 1 to 20 times as much as normal oils. The heavy oils in China have low Vanadium content. With the V : Ni ratio ranging from 111000 to 1110 of that ratio in world crude oils.