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为了更好地认识鲕粒灰岩及鲕粒云岩的溶蚀机制,并指导油气勘探,通过岩石薄片溶蚀模拟实验,结合环境扫描观察和能谱分析进行原位微观形貌观察和分析,并采用分形与多重分形对能谱面扫描图像进行分析.实验结果显示,硫酸介质下鲕粒灰岩溶蚀从结构缺陷点(解理或裂隙)开始,钙含量高的点溶蚀速率快,而钙含量低的点和含硅部分溶蚀慢或不溶蚀,从而形成凹凸不平的溶蚀坑孔隙空间;而鲕粒云岩在硫酸介质中的溶蚀从白云石晶体间裂隙开始,这是因为颗粒及颗粒间有大量微裂隙.相同条件下,鲕粒云岩的溶蚀丢失质量比鲕粒灰岩多出约80%,这表明硫酸介质对白云岩具有更强的溶蚀能力.通过对溶蚀微观形貌的观察发现,硫酸对鲕粒白云岩结构的破坏作用而形成的颗粒状表面,更有利于溶蚀作用的深入进行,进而发育优质孔隙.此外,分形与多重分形分析结果表明,碳酸盐岩薄片表面的Ca、Mg、Si含量分布的非均质性的差异控制着溶蚀反应,成分差异大、元素含量非均质性强能促进溶解反应的进行.
In order to better understand the dissolution mechanism of oolitic limestone and oolitic dolomite and to guide the exploration of oil and gas, the in situ microscopic morphology was observed and analyzed by the rock thin slice erosion simulation experiment combined with environmental scanning and energy spectrum analysis. Fractal and multifractal analysis of the energy spectrum scanning image.The experimental results show that oolitic limestone dissolution under sulfuric acid medium starts from the structural defect point (cleavage or cleavage), the point of high calcium dissolution rate is fast, and the calcium content is low Of the silicon and silicon parts of the dissolution of slow or non-corrosion, resulting in uneven karst pit pore space; and oolitic dolomite dissolution in sulfuric acid medium from the fracture between the dolomite crystals, this is because there are a large number of particles and particles In the same condition, the dissolution loss of dolomite dolomite is about 80% more than that of oolitic limestone, which shows that sulfuric acid medium has stronger dissolution ability to dolomite.According to the observation of dissolution microstructure, Sulfuric acid on the oolitic dolomite structure of the role of the formation of the granular surface is more conducive to the erosion in-depth progress, and thus the development of high-quality pores.In addition, fractal and multifractal analysis showed that carbon Ca sheet surface of the rock salt, Mg, differences in the heterogeneity of the Si content distribution control erosion reaction, large differences in composition, the content of the element strong heterogeneity can promote the dissolution reaction.