Genetic Mechanism of Paleogene Primary Heavy Oil in Sanhecun Sag of Jiyang Depression(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2018年第02期
- Page:
- 176-185
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Genetic Mechanism of Paleogene Primary Heavy Oil in Sanhecun Sag of Jiyang Depression
- Author(s):
- GAO Chang-hai; ZHANG Xin-zheng; WANG Xing-mou; ZHANG Yun-yin; LI Yu-yuan
- 1. School of Geosciences, China University of Petroleum, Qingdao 266580, Shandong, China;2. Geological Logging Company, SINOPEC Shengli Petroleum Engineering Co. Ltd., Dongying 257064, Shandong, China; 3. Geophysical Research Institute, SINOPEC Shengli Oilfield Branch Company, Dongying 257022, Shandong, China
- Keywords:
- geochemistry; primary heavy oil; low-mature oil; thermochemical sulfate reduction; biodegradation; Jiyang depression
- PACS:
- TE122.1；P618.130.1
- DOI:
- -
- Abstract:
- The Paleogene heavy oil develops in Sanhecun sag of Jiyang depression, and the misunderstanding of genetic mechanism leads to the restriction of further exploration and development. The physical properties, group composition and geochemistry characteristics of 42 heavy oil samples were analyzed; combined with the history of hydrocarbon generation and expulsion, and the characteristics of hydrocarbon migration and accumulation, the genetic mechanism of Paleogene heavy oil was discussed. The results show that the source rocks of member 4 of Shahejie Formation in Bonan sag have the condition of hydrocarbon generation with low-mature oil; at the end of Dongying period, the salt-lake facies source rocks of member 4 of Shahejie Formation enter into the low-mature evolution stage, and form low-mature oils through the early-stage hydrocarbon generations of salt reduction environment; the thermochemical sulfate reduction causes the increase of density, viscosity and sulfur content of low-mature oils, and the oils migrate at a short distance into Sanhecun sag through the unconformity carrier between Palaeogene and pre-Tertiary, and then accumulate in the stratigraphic overlap traps of member 3 of Palaeogene Shahejie Formation, and suffer from slight biodegradation due to low embedded depth, which causes further oil densification. In conclusion, the Paleogene heavy oils in Sanhecun sag belong to the primary altered type, which is mainly generated from densification of thermochemical sulfate reduction and biodegradation on low-mature oils.
Last Update: 2018-04-19