| 温压条件对非饱和低渗透砂岩中CH4突破压力影响的实验研究 |
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| 引用本文： | 赵世宇,李铱,明亮,张勇,李旭峰,郑长远.温压条件对非饱和低渗透砂岩中CH4突破压力影响的实验研究[J].地质科技通报,2021,40(3):132-139. |
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| 作者姓名： | 赵世宇 李铱 明亮 张勇 李旭峰 郑长远 |
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| 基金项目： | 国家自然科学基金41702251内蒙古自然科学基金2019MS04018江苏省煤基温室气体减排与资源化利用重点实验室创新项目2019B005青海省科学技术应用基础研究项目2018-ZJ-785 |
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| 摘 要： | 突破压力在气藏开采和盖层封闭性评价中起着重要的作用。为模拟地层温度压力变化对低渗透性砂岩中CH4突破压力的影响，采用逐步法对取自鄂尔多斯盆地早二叠世非饱和低渗透砂岩，进行了不同温压组合条件下的CH4突破压力实验。结果表明:随着温度或压力的升高，CH4突破压力和突破时间均呈下降趋势，且压力变化对CH4突破过程的影响更加显著。分析发现，温度压力对CH4突破压力的影响，是由于温压变化改变了界面张力和接触角的大小，进而控制突破压力的大小；另外，突破压力随着两相黏度比的增大而减小，且温度压力越高，黏度比对突破压力的影响越小。因此，实验温压范围内，对于非饱和低渗透砂岩储层，温度和压力越高越有利于气藏开采；对于非饱和低渗透砂岩盖层，温度和压力越低，盖层封闭性越好且越安全。
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| 关 键 词： | 温度 压力 突破压力 CH4 逐步法 低渗透砂岩 |
| 收稿时间： | 2020-07-30 |
Experimental study on the effect of temperature and pressure on CH4 breakthrough pressure in unsaturated low-permeability sandstone |
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| Abstract: | Breakthrough pressure plays an important role in gas reservoir exploitation and caprock sealing evaluation.In order to simulate the effects of temperature and pressure on CH4 breakthrough pressure in low-permeability sandstones, a step-by-step method was used to conduct CH4 breakthrough experiments on an unsaturated low-permeability sandstone from the Ordos Basin under different combinations of temperature and pressure.The results show that with the increase of temperature or pressure, the breakthrough pressure and time of CH4 show a downward trend, and the pressure change has a more significant impact on the breakthrough process of CH4.It was found that the effect of temperature and pressure on the breakthrough pressure of CH4 is due to the change of interfacial tension and contact angle, and then controls the breakthrough pressure.In addition, it was found that the breakthrough pressure decreases with the increase of the two-phase viscosity ratio; the higher the temperature and pressure, the smaller the breakthrough pressure.Therefore, within this P-T range, for the unsaturated low-permeability sandstone reservoir, the higher the temperature and pressure, the more favorable for gas reservoir development; for the unsaturated low-permeability sandstone caprock, the lower the temperature and pressure, the better the sealing property of the cap rock and the safer the caprock. |
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