页岩气水力压裂过程中压裂液—甲烷—矿物反应实验模拟研究
发布时间：2019-01-17 19:12
【摘要】：页岩气是一种环保、高效的能源,主要赋存于地壳深部的页岩层中。水力压裂是当今开采页岩气的最主要的方法。水力压裂所用的压裂液含有各种成分,可能会对地下水含水层以及地下岩层造成污染。为了探究压裂液与页岩层的反应机理,配制成分简单的压裂液,挑选我国主要页岩气产区岩层中含量较高的矿物,使用甲烷气体作为气相,利用室内高温高压反应釜模拟单矿物以及混合矿物的反应实验,并采用PHREEQC软件进行温度、压力、离子强度及离子类型等影响条件的模拟。得出的结论如下:在高温高压条件下,单矿物与压裂液在甲烷条件下发生反应,甲烷并不参与矿物的反应;由于超临界流体的性质,甲烷条件下的矿物溶解度比氮气条件下的矿物溶解程度要低大约10%。将几种不同的矿物以一定的比例混合,在高温高压条件下与压裂液在甲烷环境中发生反应。方解石不仅发生在液相中的溶解反应,同时还与呈现酸性的压裂液发生酸碱中和反应,溶解的量也要大于其他三种矿物。当p H值由初始的酸性到接近中性后,方解石的溶解反应开始变缓,方解石在体系中起到控制p H值的作用;蒙脱石的溶解程度较小,但其遇水之后吸水膨胀增大了接触面积,当矿物的结构变松散后,分子之间的作用力也会减弱,分子更容易被淋滤或者交换出来,此时蒙脱石的溶解量会增大。高岭石和石英的溶解程度较小,溶解贡献的离子浓度都较低。根据PHREEQC软件平衡模拟结果可知,甲烷的溶解程度约为1.1 mmol/L左右,而系统的p H值在稳定后会在9 10之间。温度和Na Cl浓度等因素的变化会影响四种矿物的溶解,温度越高,矿物溶解变化量越大;在一定范围内,Na Cl浓度越高,矿物溶解变化量越大。甲烷的压力对矿物的溶解变化影响很小;而在不同的水型中,由于同离子效应的产生导致矿物的溶解也有所差异。
[Abstract]:Shale gas is an environmental-friendly and efficient energy source, which mainly exists in the deep crust of shale. Hydraulic fracturing is the most important method to exploit shale gas. Fracturing fluid used in hydraulic fracturing contains various components, which may pollute groundwater aquifers and rock formations. In order to explore the reaction mechanism between fracturing fluid and shale formation, the fracturing fluid with simple composition was prepared, and the minerals with high content in rock strata in the main shale gas producing areas in China were selected, and methane gas was used as gas phase. The reaction experiments of single mineral and mixed mineral were simulated by high temperature and high pressure reactor in laboratory, and the influence conditions such as temperature, pressure, ionic strength and ion type were simulated by PHREEQC software. The conclusions are as follows: under the condition of high temperature and high pressure, the single mineral reacts with the fracturing fluid under the condition of methane, and methane does not participate in the reaction of minerals; Because of the properties of supercritical fluid, the solubility of minerals in methane is about 10. 0% lower than that in nitrogen. Several different minerals were mixed in a certain proportion and reacted with fracturing fluid in methane environment under high temperature and high pressure. Calcite not only dissolves in liquid phase, but also neutralizes acid and base with acid fracturing fluid. The amount of dissolution of calcite is larger than that of other three minerals. When pH value changes from initial acidity to neuter, the dissolution of calcite begins to slow down, and calcite plays a role in controlling pH value in the system. The dissolution of montmorillonite is relatively small, but the water swelling increases the contact area after it meets water. When the mineral structure becomes loose, the interaction between molecules will weaken, and the molecules will be more easily leached or exchanged out. At this time, the dissolution of montmorillonite will increase. The dissolution degree of kaolinite and quartz is smaller and the ion concentration of dissolution contribution is lower. According to the results of PHREEQC software equilibrium simulation, the solubility of methane is about 1.1 mmol/L, and the pH value of the system is between 9 and 10 after stabilization. The changes of temperature and Na Cl concentration will affect the dissolution of the four minerals. The higher the temperature, the greater the change of mineral dissolution, and the higher the concentration of, Na Cl in a certain range, the greater the change of mineral dissolution. The pressure of methane has little effect on the dissolution of minerals, but in different water types, the dissolution of minerals is also different due to the production of the same ion effect.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE377
本文编号：2410289
[Abstract]:Shale gas is an environmental-friendly and efficient energy source, which mainly exists in the deep crust of shale. Hydraulic fracturing is the most important method to exploit shale gas. Fracturing fluid used in hydraulic fracturing contains various components, which may pollute groundwater aquifers and rock formations. In order to explore the reaction mechanism between fracturing fluid and shale formation, the fracturing fluid with simple composition was prepared, and the minerals with high content in rock strata in the main shale gas producing areas in China were selected, and methane gas was used as gas phase. The reaction experiments of single mineral and mixed mineral were simulated by high temperature and high pressure reactor in laboratory, and the influence conditions such as temperature, pressure, ionic strength and ion type were simulated by PHREEQC software. The conclusions are as follows: under the condition of high temperature and high pressure, the single mineral reacts with the fracturing fluid under the condition of methane, and methane does not participate in the reaction of minerals; Because of the properties of supercritical fluid, the solubility of minerals in methane is about 10. 0% lower than that in nitrogen. Several different minerals were mixed in a certain proportion and reacted with fracturing fluid in methane environment under high temperature and high pressure. Calcite not only dissolves in liquid phase, but also neutralizes acid and base with acid fracturing fluid. The amount of dissolution of calcite is larger than that of other three minerals. When pH value changes from initial acidity to neuter, the dissolution of calcite begins to slow down, and calcite plays a role in controlling pH value in the system. The dissolution of montmorillonite is relatively small, but the water swelling increases the contact area after it meets water. When the mineral structure becomes loose, the interaction between molecules will weaken, and the molecules will be more easily leached or exchanged out. At this time, the dissolution of montmorillonite will increase. The dissolution degree of kaolinite and quartz is smaller and the ion concentration of dissolution contribution is lower. According to the results of PHREEQC software equilibrium simulation, the solubility of methane is about 1.1 mmol/L, and the pH value of the system is between 9 and 10 after stabilization. The changes of temperature and Na Cl concentration will affect the dissolution of the four minerals. The higher the temperature, the greater the change of mineral dissolution, and the higher the concentration of, Na Cl in a certain range, the greater the change of mineral dissolution. The pressure of methane has little effect on the dissolution of minerals, but in different water types, the dissolution of minerals is also different due to the production of the same ion effect.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE377
【参考文献】
相关期刊论文 前1条
1 聂海宽;张金川;;页岩气聚集条件及含气量计算——以四川盆地及其周缘下古生界为例[J];地质学报;2012年02期
，本文编号：2410289
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