深部咸水层条件下钾长石有序度对其与CO2反应速率的影响研究

矿物封存是深部咸水层封存CO2的重要机制。目前矿物封存的研究集中在矿物成分方面，主要探究与CO2反应的储层矿物和新生成矿物的种类。矿物晶体结构对矿物与CO2反应的影响没得到足够的重视。钾长石是常见的储层矿物，其有序度反映了晶体中Al-Si分布的有序程度，是钾长石晶体结构的重要指标。随着结晶温度的降低，钾长石的有序度逐渐升高。深部咸水层中钾长石的溶解过程可以看作是不同条件下钾长石结晶过程的逆反应，因此我们推测在富含CO2的咸水层中，随着钾长石有序度的升高，其溶解速率会逐渐降低。为了验证该假设，我们选择结晶温度不同的钾长石系列样品——透长石、正长石和微斜长石，首先测定其有序度，然后模拟深部咸水层中CO2-咸水-钾长石的反应过程，测定钾长石的反应速率，最后分析钾长石结构有序度对其与CO2反应速率的影响。本项目将为CO2矿物封存开辟一个新的研究方向，揭开研究晶体结构对CO2矿物封存的影响的新篇章。

Mineral sequestration is one of the most mechanisms of sequestrating CO2 in deep saline aquifers. Present researches on mineral sequestrations focus on mineral composition and they mainly explore reservoir minerals reacting with CO2 and new substances produced, while the influence of crystal structure on reaction of minerals with CO2 has not been paid enough attention. Potassium feldspar is a common reservoir mineral. Its order degree shows degree of order of Al-Si distribution of feldspar crystal, and it is an important indicator of crystal structure of potassium feldspar. The order degree of potassium feldspar rises along with decline of crystallization temperature. The dissolution process of potassium feldspar in deep saline aquifers can be seen as the reverse reaction of crystallization process in different conditions. We speculate the dissolution rate of potassium feldspar may decline with the rising of its order degree in deep saline aquifers rich in CO2. In order to test this hypothesis, we plan to choose a series of potassium feldspars, such as sanidine, orthoclase and microcline. First of all, we will measure their order degree; then we will perform the reaction of CO2 - saline water - feldspar in conditions of deep saline aquifers in high-temperature and high-pressured tank. After this reaction, we will measure reaction rate of potassium feldspar and then analyze influence of order degree of potassium feldspar on its reaction rate with CO2. This project will open up a new research direction of mineral sequestration and uncover a new chapter of researching influence of crystal structure on CO2 mineral sequestration.