| 干酪根对页岩基质中甲烷运移规律的影响 |
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| 引用本文： | 王金杰,于龙,苑庆旺,何文波,郭超华.干酪根对页岩基质中甲烷运移规律的影响[J].地球科学,2017,42(8):1386-1393. |
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| 作者姓名： | 王金杰 于龙 苑庆旺 何文波 郭超华 |
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| 作者单位： | 1.中国地质大学资源学院, 湖北武汉 430074 |
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| 基金项目： | 中国地质大学（武汉）杰出人才培育基金项目G1323541746 |
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| 摘 要： | 微/纳米孔隙内甲烷的运移研究是进行页岩气藏开发预测及评价的前提和基础.页岩中分布大量的微/纳米孔隙，其中干酪根中的纳米级孔隙分布广泛.由于气体在不同尺度孔隙中的运移机理大不相同，且在有机孔中存在明显的吸附/解吸现象.因而，甲烷在页岩中的运移机理仍需完善.本研究综合物理模拟及数学分析方法，对甲烷渗流规律进行研究.研究结果表明:（1）温度升高，单位质量页岩的产量减少，达到平衡的时间缩短，总体体现在甲烷在高温下的吸附/解吸-扩散速率大.（2）相同生产压力下，随入口压力升高，甲烷运移速率增大，达到产量平衡的时间增长.（3）数学模型充分考虑干酪根中甲烷扩散对气体运移过程的影响，并与实验结果及不考虑干酪根影响的模型进行对比分析，结果显示，本文建立的数学模型能更准确地描述甲烷在页岩基质中的运移动态.
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| 关 键 词： | 页岩 干酪根 吸附/解吸 扩散 动态实验 |
| 收稿时间： | 2017-03-31 |
Effect of Kerogen on the Methane Transport Mechanism in Shale Matrix |
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| Abstract: | It is essential to understand methane mass transport through micro/nano pores in shale for the reservoir evaluation and gas production prediction. There distributes large numbers of pores, including micropores, mesopores and macropores. Kerogen, as the organic matter in shale, is rich in micro/meso-pores with width less than 50 nm. Multiple gas transport mechanisms coexist in porous media with complex pore size distribution, including viscous flow and Knudsen diffusion of free gas, and surface diffusion of adsorbed gas. During pressure depletion of a reservoir, the adsorbed gas desorbs into pore space as additional "free gas", and meanwhile, diffuses along the surface of nanopores in porous media. In this paper, experimental and calculated results for the gas transport in nanopores of shale matrix are presented, accounting for the effect on dynamic transport process of surface diffusion. The main conclusions are:(1) the equilibrium time for gas transport process decreases very quickly with temperature and less gas produced under higher temperature; (2) higher saturation pressure could accelerate the process and increase the amount of produced gas; (3) the mathematical model considers the effect of kerogen on the methane transport. Compared with the models not considering the effect of kerogen, the model presented in this paper fits the experimental results better. This study provides an experimental investigation of the methane mass transport through shale matrix considering the effect of kerogen, which is a relatively simple but information-rich technique for the assessment of shale gas targets. |
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