四川盆地焦石坝地区页岩吸附特征室内实验

发布时间：2018-02-01 11:06

  本文关键词： 龙马溪组页岩 吸附气 游离气 等温吸附/解吸 压力　出处：《天然气地球科学》2017年09期 　论文类型：期刊论文

【摘要】：页岩含气量对页岩气田储量计算至关重要,直接关系到页岩气的产量、递减规律等。页岩气以游离气和吸附气形式赋存,有重量法等温吸附、容量法等温吸附、现场含气量测试等不同方法测试吸附气、游离气。通过测试页岩气降压解吸过程中气体体积变化来测量吸附气量,首次建立了同时测试页岩吸附气、游离气的方法。该方法采用柱状页岩岩心,模拟不同温度、压力、含水、真实孔隙结构等条件,消除了等温吸附曲线的负吸附异常;分析了有机质含量、压力、温度、含水、气体组成等因素对页岩吸附量的影响。实验结果表明,页岩的甲烷吸附量随压力增加而增加,压力大于12MPa后达到吸附/解吸动态平衡,吸附量不再增加;有机质含量TOC增加时吸附量增加;温度增加时吸附量降低;页岩含水后吸附量降低;甲烷吸附量高于氮气吸附量;焦石坝龙马溪组主力层页岩在温度20℃、压力30MPa下页岩气吸附气量介于1.8~3.1m~3/t之间,总含气量介于5.1~6.5m~3/t之间,吸附气占总气量40%左右。
[Abstract]:Shale gas content is very important to the calculation of shale gas reserves, which is directly related to the production and decline of shale gas. Shale gas occurs in the form of free gas and adsorption gas, with isothermal adsorption by gravimetric method and isothermal adsorption by capacity method. The adsorption gas volume was measured by measuring the volume change of the gas during the depressurization and desorption of shale gas, and the simultaneous measurement of the shale adsorbed gas was established for the first time. The method uses columnar shale core to simulate the conditions of different temperature, pressure, water content and real pore structure, thus eliminating the negative adsorption anomaly of isothermal adsorption curve. The effects of organic matter content, pressure, temperature, water content and gas composition on the adsorption capacity of shale are analyzed. The experimental results show that the methane adsorption capacity of shale increases with the increase of pressure. When the pressure is more than 12MPa, the adsorption / desorption dynamic equilibrium is reached, and the adsorption amount is no longer increased. When the content of organic matter (TOC) increased, the adsorption capacity increased. The adsorption capacity decreases with the increase of temperature. The adsorption capacity of shale decreases after water cut. The adsorption capacity of methane is higher than that of nitrogen. At 20 鈩，

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