Next Article in Journal
The Role of Magma Mixing in Generating Granodioritic Intrusions Related to Cu–W Mineralization: A Case Study from Qiaomaishan Deposit, Eastern China
Previous Article in Journal
Deep Mineral Exploration of the Jinchuan Cu–Ni Sulfide Deposit Based on Aeromagnetic, Gravity, and CSAMT Methods
Open AccessArticle

Coupling between Diagenetic Environment and Porosity Evolution—A Quantitative Study of the Zhuhai Formation in the Huizhou Sag, Pearl River Mouth Basin, South China Sea

by Xuan Cao 1,2, Dakang Zhong 1,2,*, Jie Liu 3, Haitao Sun 1,2, Zezhang Song 1,2,*, Tianyu Cao 1,2, Fei Wang 3 and Shuangyi Gong 1,2
1
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China
2
College of Geosciences, China University of Petroleum, Beijing 102249, China
3
Shenzhen Branch, China National Offshore Oil Corporation, Shenzhen 518000, China
*
Authors to whom correspondence should be addressed.
Minerals 2020, 10(2), 170; https://doi.org/10.3390/min10020170
Received: 27 December 2019 / Revised: 11 February 2020 / Accepted: 12 February 2020 / Published: 14 February 2020
(This article belongs to the Section Mineral Deposits)
The diagenetic environment is vital in controlling reservoir quality by influencing diagenetic processes, especially porosity evolution. The Zhuhai Formation is a critical exploration target in the Huizhou Sag. However, there are considerable differences between the reservoirs in the west (Huixi) and east (Huidong) Huizhou Sag with only a 400 m difference in burial depth. To investigate causes of these differences, scanning electron microscopy (SEM), cathodoluminescence analysis, fluorescence analysis, and fluid inclusion analysis are employed for the petrological and diagenetic characterization of the target formation. Moreover, image analysis software is used to qualitatively evaluate the impacts of diagenesis on porosity. The results show that the digenetic environments in Huixi and Huidong are different. Huixi is characterized by a high content of feldspar with a stronger dissolution phenomenon than that observed in Huidong. The main cement types in Huixi are siliceous cement and kaolinite. Moreover, Huixi had a low palaeo-temperature, low palaeo-salinity, and low palaeo-pH diagenetic environment. In contrast, Huidong is accessible via deep faults and rich in lithic fragments which show visible deformation. Moreover, cements in this area include carbonate, gypsum, quartz overgrowth, kaolinite, and chlorite. This evidence confirms that the diagenetic environment in Huidong was a high palaeo-temperature and high palaeo-salinity environment with high palaeo-pH. Additionally, the palaeo-pH evolved following the sequence of weakly alkaline, acidic, alkaline and acidic. Microscopy evidence indicates that the Dongsha Uplift was a likely source of Huixi sediments during the deposition of the Zhuhai Formation. The determination of the porosity evolution shows that compaction and lithic fragment content are the main controlling factors on the reservoir quality of the Zhuhai Formation.
Keywords: diagenetic environment; diagenesis; porosity evolution; the Zhuhai Formation diagenetic environment; diagenesis; porosity evolution; the Zhuhai Formation
MDPI and ACS Style

Cao, X.; Zhong, D.; Liu, J.; Sun, H.; Song, Z.; Cao, T.; Wang, F.; Gong, S. Coupling between Diagenetic Environment and Porosity Evolution—A Quantitative Study of the Zhuhai Formation in the Huizhou Sag, Pearl River Mouth Basin, South China Sea. Minerals 2020, 10, 170.

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