Characteristics and Significance of Acid-Soluble Organic Matter in Marine Carbonate Source Rocks
Abstract
:1. Introduction
2. Samples and Methods
2.1. Samples
2.2. Instruments and Experimental Methods
3. Results and Discussion
3.1. Comparison of TOC Results Obtained Using Different Methods
3.2. Relationship between Acid-Soluble Organic Matter Content and TOC
3.3. Factors Affecting the Abundance of Acid-Soluble Organic Matter
3.3.1. Thermal Evolution
3.3.2. Carbonate Minerals
3.3.3. Depositional Environment
4. Conclusions
- (1)
- In this study, the characteristics and significance of acid-soluble organic matter in marine carbonate source rocks are discussed. The problem of low TOC measurements caused by the loss of large amounts of organic matter during traditional TOC pretreatment is solved, and a new idea for the evaluation of marine carbonate source rocks is provided.
- (2)
- For most samples, the TOC+ values measured by the new method are higher than the conventional TOC values. The loss of organic matter during conventional TOC testing of some carbonate rock samples from the Eagle Ford Formation accounted for more than half of the total organic matter.
- (3)
- There is no obvious positive correlation between the content of acid-soluble organic matter and TOC. Furthermore, there is a pronounced negative correlation between the content of acid-soluble organic matter of carbonate rocks in the Permian Maokou Formation in the Sichuan Basin and conventional TOC. Additionally, the relative proportion of acid-soluble organic matter to total organic matter has an obvious positive correlation with the mineral content of carbonate rocks.
- (4)
- The content of acid-soluble organic matter is affected by many factors. There is a certain negative correlation between the content of acid-soluble organic matter and the thermal maturity of organic matter, but low-maturity carbonate rocks are not necessarily rich in organic acid salts. The development of acid-soluble organic matter should be considered along with other influencing factors.
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Scholar | TOC Lower Limit/% | Scholar | TOC Lower Limit/% |
---|---|---|---|
Hunt [19] | 0.29 | Liu B. Q. et al. [20] | 0.05 |
Palacas [21] | 0.40 | Chen P. J. et al. [18] | 0.1 |
Tissot et al. [22] | 0.30 | Hao S. S. et al. [23] | 0.2 |
Fu J.M. et al. [17] | 0.1–0.2 | Liang D. G. et al. [24] | 0.5 |
Xia X.Y. et al. [25] | 0.4–0.5 | Peng P. A. et al. [26] | 0.1 |
Sample | Strata | Stage of Thermal Evolution | TOC Distribution Range (%) | Mineral Content of Carbonate Rock (%) | Depositional Environment | Organic Matter Type |
---|---|---|---|---|---|---|
Majiagou Formation | Ordovician | High-over mature (1.6–2.5%) | 0.01–1.67 | 40.2–99.1 | Restricted open carbonate platform | Type I |
Maokou Formation | Permian | Low mature-mature (0.8–1.5%) | 0.16–2.36 | 9.4–69.4 | Open carbonate platform; slope facies | Type II |
Xiaoerbulake Formation | Cambrian | High-over mature (1.8–2.5%) | 0–0.61 | 45–78 | Carbonate gentle slope facies | Type I/II |
the Eagle Ford carbonate rocks | K | Low mature-mature (0.6–1.2%) | 0.09–6.16 | >45 | Littoral shallow marine environment | Type II |
Samples | Lithology | Formation | TOC (Conventional)/% | TOC+ (New Method)/% | δ13C/‰ |
---|---|---|---|---|---|
Tsgt-3 | Oily bituminous limestone | Xiaoerbulake Formation | 0.08 | 0.60 | −31.9 |
Tsgt-4 | Shale interlayers | Xiaoerbulake Formation | 0.61 | 1.41 | −31.3 |
Tsgt-5 | argillaceous limestone | Xiaoerbulake Formation | 0.47 | 1.18 | −32.1 |
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Feng, D.; Wang, X.; Liu, W.; Zhang, D.; Wang, J.; Luo, H.; Liu, P. Characteristics and Significance of Acid-Soluble Organic Matter in Marine Carbonate Source Rocks. Energies 2023, 16, 2017. https://doi.org/10.3390/en16042017
Feng D, Wang X, Liu W, Zhang D, Wang J, Luo H, Liu P. Characteristics and Significance of Acid-Soluble Organic Matter in Marine Carbonate Source Rocks. Energies. 2023; 16(4):2017. https://doi.org/10.3390/en16042017
Chicago/Turabian StyleFeng, Danting, Xiaofeng Wang, Wenhui Liu, Dongdong Zhang, Jie Wang, Houyong Luo, and Peng Liu. 2023. "Characteristics and Significance of Acid-Soluble Organic Matter in Marine Carbonate Source Rocks" Energies 16, no. 4: 2017. https://doi.org/10.3390/en16042017
APA StyleFeng, D., Wang, X., Liu, W., Zhang, D., Wang, J., Luo, H., & Liu, P. (2023). Characteristics and Significance of Acid-Soluble Organic Matter in Marine Carbonate Source Rocks. Energies, 16(4), 2017. https://doi.org/10.3390/en16042017