页岩吸附气含量测定的影响因素定量分析

发布时间：2018-05-01 12:09

本文选题：页岩气 + 等温吸附　；参考：《天然气地球科学》2016年03期

【摘要】：页岩气是一种重要的非常规天然气资源,页岩吸附气含量的准确测定是正确评价页岩含气量和资源潜力的关键参数。通常采用等温吸附实验的方法确定页岩吸附气含量。但是,现在多数情况下页岩高压时的吸附量出现负值,等温吸附曲线特征也呈现下降形态,与以往在煤层气领域的认识明显不同。为了正确解释此种现象,研究中选取了国际页岩吸附量测定对比的标准样品(Kimmeridge页岩、Posidonia页岩)以及我国四川盆地龙马溪组和塔里木盆地奥陶系页岩等样品,开展了一系列的等温吸附实验和数值计算,对页岩吸附气含量测定的影响因素进行了半定量—定量分析。研究表明,气体状态方程、自由空间体积、压力传感器精度和空白测试等是影响页岩吸附气含量测定的主要因素。气体状态方程中,Se-W方程最适用于页岩的甲烷吸附量计算,其次是S-R-K方程,最差的是P-R方程。自由空间体积与吸附量呈负相关关系,即自由空间体积偏大,吸附量比实际减小;相反,自由空间体积偏小,吸附量结果比实际大,高压条件下对吸附量的影响更为明显。相对于温度传感器,压力传感器精度对页岩甲烷吸附量的影响更为突出,万分之一精度压力传感器的等温吸附实验结果比千分之一精度的更精确。此外,未经过空白测试校正的页岩吸附量通常比实际吸附量低,且会导致吸附量出现负值。因此,开展页岩吸附气含量的测定需要对影响因素进行系统的认识和相应的校正。
[Abstract]:Shale gas is an important unconventional natural gas resource. The accurate determination of shale adsorption gas content is the key parameter to correctly evaluate the gas content and resource potential of shale. The adsorption gas content of shale is determined by the method of isothermal adsorption. However, the adsorption amount of shale at high pressure is negative in most cases and isothermal adsorption curve in most cases. In order to correctly explain this phenomenon, the international standard samples (Kimmeridge shale, Posidonia shale) and samples of the Sichuan basin and the Ordovician shale in the Sichuan basin and the Tarim Basin were selected for the correct interpretation of this phenomenon. A series of isothermal adsorption experiments and numerical calculations have been used to make a semi quantitative and quantitative analysis of the factors affecting the determination of shale adsorption gas content. The study shows that the gas state equation, free space volume, pressure sensor precision and blank test are the main factors affecting the determination of shale adsorption gas content. In gas state equation, Se-W equation It is the most suitable for the calculation of methane adsorption of shale, followed by the S-R-K equation, and the worst is the P-R equation. The volume of free space has a negative correlation with the amount of adsorption, that is, the volume of free space is larger and the adsorption amount is smaller than the actual. On the contrary, the volume of free space is smaller, the adsorption amount is larger than that in the real world, and the effect on the adsorption amount is more obvious under the condition of high pressure. Compared with the temperature sensor, the effect of the pressure sensor precision on the adsorption of shale methane is more prominent, and the results of the isothermal adsorption experiment of the 1/10000 precision pressure sensor are more accurate than the 1/1000 precision. In addition, the shale adsorption quantity which is not corrected by the blank test is usually lower than the actual adsorption quantity, and it will lead to the negative amount of adsorption. Therefore, the determination of shale gas content should be systematically understood and corrected accordingly.

【作者单位】：中国石油勘探开发研究院;中国石油天然气集团公司盆地构造与油气成藏重点实验室;提高石油采收率国家重点实验室;
【基金】：中国石油天然气股份公司“十二五”科技攻关课题(编号:2014A-0214)资助
【分类号】：P618.13

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