摘要：Dolomitization, as one of the most important diagenetic processes in carbonate reservoirs, is essential for reservoir porosity development and evolution. However, the geochemical mechanism of dolomitization is unclear. In this study, theoretical analysis, laboratory physical experiments, thermodynamic calculation and computer numerical simulation were combined to explore the coupled effects of temperature and solution compositions on dolomitization. A series of water-rock reaction experiments at various temperature were firstly carried out. X-ray diffraction (XRD), scanning electron microscope (SEM), ICP-MASS and other analytical methods were used to monitor ion concentration, relative content and surface morphology of all minerals. Secondly, molecular dynamics (MD) simulation and thermo-hydro-chemical (THC) coupling simulation were employed to analyze various processes of dissolution, precipitation and transformation of carbonate rock. Finally, combining thermodynamic calculation, coupled effects of temperature and solution compositions on dolomitization were determined and the optimum formation conditions of dolomite were confirmed. Dolomitization experienced a series of transitional processes from calcite -> Mg-bearing calcite -> high-calcium dolomite -> low-calcium dolomite. At 60 degrees C, 80 degrees C and 95 degrees C, the equilibrium constants of dolomitization are 1.67, 1.75 and 1.80, respectively. Dolomite is formed when Mg/Ca ratio equals 5.3 (at 95 degrees C) and the scope activity of Mg2+ is 32.91-54.52%. It would need a much higher activated Mg2+ or it may be impossible to form dolomite if the Mg/Ca ratio is less than 3. This study has revealed coupled effects of temperature and solution compositions on metasomatism dolomitization, which could provide a basis for evaluating and predicting high-quality carbonate reservoirs.

关键字：Carbonate reservoir; Dolomitization; Coupled effects; Temperature; Solution compositions; Controlling factors

ISSN号：0022-1694

卷、期、页：卷604:127199

发表日期：2022-01-01

影响因子：5.721500

期刊分区（SCI为中科院分区）：二区

收录情况：SCI（科学引文索引印刷版）,地学领域高质量科技期刊分级目录（国外T1）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：Journal of Hydrology

参与作者：刘可禹,朱光有

通讯作者：于林姣

第一作者：杨磊磊,贾冀辉,刘琦

论文类型：期刊论文

论文概要：杨磊磊,于林姣,刘可禹,贾冀辉,朱光有,刘琦，Coupled effects of temperature and solution compositions on metasomatic dolomitization: Significance and implication for the formation mechanism of carbonate reservoir，Journal of Hydrology，2022，卷604:127199

论文题目：Coupled effects of temperature and solution compositions on metasomatic dolomitization: Significance and implication for the formation mechanism of carbonate reservoir