Diamondoids and biomarkers: as a tool to better define the effects of thermal cracking and microbial oxidation on oils/condensates from reservoirs of the Upper Indus Basin, Pakistan
| Autor: | Thomas S. Bianchi, Muhammad Irfan Jalees, Fazeelat Tahira, Roger Sassen |
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| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | Carbonates and Evaporites. 26:155-165 |
| ISSN: | 1878-5212 0891-2556 |
| DOI: | 10.1007/s13146-011-0042-9 |
| Popis: | The present study examined crude oils and condensates from 12 productive oil field zones present in the Upper Indus Basin, Pakistan, located at 33°11′00″N to 33°56′00″N and 73°10′00″ to 73°56′00″E. These crude oils and condensates belonged to Eocene, Paleocene, and Jurassic ages. GC and GC–MS parameters revealed that these samples were mature and contained marine and algal/bacterial organic matter sources from an oxidizing environmental/dysoxic environment. The total methyladamantanes/admantane ratio varied from 4.05 to 15.25 and showed increasing levels of microbial oxidation. The diamantane/adamantane ratio varied from 1.14 to 3.06, and total methyldiamantanes/diamantane ratio also supports the results. The degree and classification of microbial oxidation in different crude oils and condensates were best defined by plotting American Petroleum Institute gravity versus diamondoid concentrations. Diamondoid parameters indicated a maturity of samples but the levels of maturity were different based on the particular diamondoid maturity parameter used, which varied considerably. This study further demonstrated that utilization of both biomarkers and diamondoids provided the best approach for determining the maturity level of crude oils and condensates. |
| Databáze: | OpenAIRE |
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