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标题：AN EXPERIMENTAL STUDY ON THE FACTORS CONTROLLING CARBONATE ROCK DISSOLUTION UNDER WIDE RANGE OF TEMPERATURE AND PRESSURE
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作者：Jianwen Gao ; Dazhong Ren ; Wei Sun 等
期刊名称：Fresenius Environmental Bulletin
印刷版ISSN：1018-4619
出版年度：2020
卷号：29
期号：8
页码：6672-6685
语种：English
出版社：PSP Publishing
摘要：In recent years, hydrocarbon exploration has revealed that marine carbonate rocks in deep strata have the potential to be prospective reservoirs. In order to study the factors (i.e. solution flow rate, temperature, pressure, the properties of the solution, and the m ineral composition of the carbonate rocks) that affect carbonate rock dissolution in a deep burial environm ent, a series of carbonate rock- water dissolution experiments were conducted at temperatures/pressures ranging from 40°C / 10 MPa to 140°C / 50 MPa. A ll reaction solutions were unsaturated w ith respect to calcite and dolom ite, including deionized water, gypsum-rock solution, salt-rock solution, and CO2 aqueous solution. The main elements of each reaction solution were tested before and after the experiment using an ion chromatograph. Meanwhile, scanning electron m icroscopy and CT-scanning technology were used to observe rock samples before and after dissolution. The experimental results revealed that: (1) temperature is the fundamental factor in controlling dissolution of carbonate, however, at temperatures greater than 100 °C is not conducive to the dissolution of carbonate rocks, (2) due to the common ion effect and ionic strength effect, the ground water properties play a significant role in carbonate rock dissolution, and (3) hydrogen supply capacity of acidic substances is an im portant determinant in carbonate dissolution. When temperature and pressure exceed 90°C / 30 MPa, the concentration of H + produced by the ionization of CO2 aqueous solution drops, nevertheless, it s till has strong dissolution capacity and improves the perm eability and porosity of carbonate rock. Therefore, the enrichment area and distribution of acidic substances provide a direction for predicting high-quality carbonate reservoirs.
关键词：Carbonate rock dissolution;Deep burial environment;Salt-rock solution;Gypsum-rock solution;Closed system;Flow system