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IN-RESERVOIR FRACTIONATION AND THE ACCUMULATION OF OIL AND CONDENSATES IN THE SURMA BASIN, NE BANGLADESH
| Title: | IN-RESERVOIR FRACTIONATION AND THE ACCUMULATION OF OIL AND CONDENSATES IN THE SURMA BASIN, NE BANGLADESH |
| Authors: | Hossain, Md. A. Browse this author | | Suzuki, N. Browse this author →KAKEN DB | | Matsumoto, K. Browse this author | | Sakamoto, R. Browse this author | | Takeda, N. Browse this author |
| Keywords: | Sylhet trough | | Surma basin | | evaporative fractionation | | condensates | | waxy oils | | naphthalene | | diamondoid | | tertiary migration |
| Issue Date: | Jul-2014 |
| Publisher: | Wiley |
| Journal Title: | Journal of Petroleum Geology |
| Volume: | 37 |
| Issue: | 3 |
| Start Page: | 269 |
| End Page: | 286 |
| Publisher DOI: | 10.1111/jpg.12583 |
| Abstract: | Petroleum in the Surma basin, NE Bangladesh (part of the Bengal Basin) ranges from waxy crude oils to condensates. The origin and source rocks of these hydrocarbons were investigated based on the distributions of saturated and aromatic hydrocarbons in 20 oil samples from seven oil and gas fields. The relative compositions of pristane, phytane and adjacent n-alkanes suggest that the source rock was deposited in a non-marine setting. The abundance and similar distribution of biphenyls, cadalene and bicadinanes in most of the crude oils and condensates indicates a significant supply of higher-plant derived organic matter to the source rocks. Maturity levels of the crude oils and condensates from the Surma basin correspond to calculated vitrinite reflectance (Rc) values of 1.0–1.3%, indicating hydrocarbon expulsion from the source rock at a comparatively high maturity level. The Rc values of oils from the Titas field in the southern margin of the Surma basin are relatively low (0.8–1.0%). Some oils were severely biodegraded. The similar distribution of diamondoid hydrocarbons in both biodegraded and non-biodegraded oils indicated similar types of source rocks and similar maturity levels to those of oils from the Surma basin. The Oligocene Jenam Shale and/or underlying non-marine deposits located at greater depths may be potential source rocks. The diversity of the petroleum in the Surma basin was likely due to evaporative fractionation, resulting in residual waxy oils and lighter condensates which subsequently underwent tertiary migration and re-accumulation. Evaporative fractionation due to modification of the reservoir structure occurred during and after the Pliocene, when large-scale tectonic deformation occurred in and around the Bengal Basin. |
| Rights: | This is the peer reviewed version of the following article: IN-RESERVOIR FRACTIONATION AND THE ACCUMULATION OF OIL AND CONDENSATES IN THE SURMA BASIN, NE BANGLADESH, which has been published in final form at http://dx.doi.org/10.1111/jpg.12583. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/59572 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 鈴木 徳行
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