Origin of dedolomite in the Carboniferous of Eastern Sichuan basin and its geological significance
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- 作者：Wen Huaguo ; Cao Jixiang ; Wen Longbin ; Zheng Rongcai
- 刊名：Carbonates and Evaporites
- 出版年：2016
- 出版时间：September 2016
- 年：2016
- 卷：31
- 期：3
- 页码：249-257
- 全文大小：2,151 KB
- 刊物类别：Earth and Environmental Science
- 刊物主题：Geology
Earth sciences
Mineral Resources
Mineralogy - 出版者：Springer Berlin Heidelberg
- ISSN：1878-5212
- 卷排序：31
文摘
Resulting in dense lithology and poor physical properties, dedolomitization has detrimental effects on reservoir characteristics, so there has been little systematic research reported on the dedolomitization in the Carboniferous Huanglong Formation from the Eastern Sichuan basin. Through well drilling, well logging, thin-section authentication, and geochemistry tests, we studied for the first time the growth characteristics, regularities of distribution, genesis, and geological significance of dedolomitization in rock with typical fabric. From this study, we arrived at three conclusions: (1) the microstructure type divisions of dedolomite are as follows: A. a large micrite core and clear calcite rim, B. dolomite crystal, C. gypsum crystal, and D. rhombohedral pores; (2) rocks had low porosity and high density after dedolomitization in Eastern Sichuan, which is detrimental to reservoir development; and (3) micrite–microlite crystal dolomite and micrite–microlite crystal gypsum dolomite are the protoliths before dedolomitization. Sabkha is the primary sedimentary environment, in which the sabkha brine was kept within the layer and would become the main fluid of dolomitization in the high-quality dolomite reservoir from Eastern Sichuan. Analyzing the instances of dedolomitization has important geological significance in some ways, such as recovering the protolith, recovering the ancient environment, and discussing the relationships between diagenetic fluid properties and the reservoir’s development.KeywordsDedolomitizationDedolomiteOriginPaleokarstCarboniferousEastern Sichuan basin