Next Article in Journal
A Building Block Method for Modeling and Small-Signal Stability Analysis of the Autonomous Microgrid Operation
Previous Article in Journal
A Study of Temperature-Dependent Hysteresis Curves for a Magnetocaloric Composite Based on La(Fe, Mn, Si)13-H Type Alloys
Open AccessArticle

Impact of the Paleoclimate, Paleoenvironment, and Algae Bloom: Organic Matter Accumulation in the Lacustrine Lucaogou Formation of Jimsar Sag, Junggar Basin, NW China

by Yuhan Jiang 1,2,3,*, Dujie Hou 1,2,3,*, Hang Li 4, Ziming Zhang 1,2,3 and Ruibo Guo 1,2,3
1
School of Energy Resources, China University of Geosciences, Beijing 100083, China
2
Key Laboratory of Shale Gas Exploration and Evaluation, Ministry of Land and Resources, China University of Geosciences, Beijing 100083, China
3
Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China
4
No.8 Oil Recovery Plant of PetroChina Changqing Oilfield Company, Xi’an 710016, China
*
Authors to whom correspondence should be addressed.
Energies 2020, 13(6), 1488; https://doi.org/10.3390/en13061488
Received: 5 February 2020 / Revised: 5 March 2020 / Accepted: 20 March 2020 / Published: 21 March 2020
Shale oil exploration has been a key area of onshore oil and gas exploration in China in recent years. In this study, organic geochemistry and element geochemistry are united to study the shale oil and source rock in the Lucaogou formation of Jimusar sag, in order to reveal the paleoclimate, paleoenvironment, source of organic matter, and factors affecting organic matter accumulation and shale oil generation. The shale oil in the study area is mainly accumulated in two strata with good reservoir properties and oiliness, known as the upper sweet spot and lower sweet spot. Indexes of biomarkers and sensitive elements revealed the warm and semi-arid paleoclimate during Lucaogou formation, and the water column was brackish to salty. Water stratification caused a suboxic to anoxic environment in the deep-water column and coincided with the anoxic photic zone phenomenon. Compared with the lower sweet spot, the more humid climate, deeper and fresher water, and stronger water stratification characterize the upper sweet spot during sedimentation. This made the photic zone with freshwater more suitable for the reproduction of algae in the upper sweet spot. Meanwhile, the organic matter was well-preserved in the anoxic zone. Volcanic ash caused algae bloom, which promoted primary productivity and ensured the supply of organic matter. The composition and distribution pattern of biomarkers prove that phytoplankton is the most important source of organic matter in the study area and the contribution of higher plants is insignificant. The relationship between parameters of paleoproductivity and the redox condition versus total organic carbon (TOC) suggests that compared with the preservation conditions, the input of organic carbon is the most important controlling factor of organic matter accumulation in the study area. View Full-Text
Keywords: shale oil; geochemistry; biomarkers; volcanic ash; aryl isoprenoids; brackish lacustrine water shale oil; geochemistry; biomarkers; volcanic ash; aryl isoprenoids; brackish lacustrine water
Show Figures

Figure 1

MDPI and ACS Style

Jiang, Y.; Hou, D.; Li, H.; Zhang, Z.; Guo, R. Impact of the Paleoclimate, Paleoenvironment, and Algae Bloom: Organic Matter Accumulation in the Lacustrine Lucaogou Formation of Jimsar Sag, Junggar Basin, NW China. Energies 2020, 13, 1488.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop