地质力学学报  2018, Vol. 24 Issue (4): 498-504
 引用本文

RAN Yanxia, YE Bin, CHENG Zirui. RESEARCH PROGRESS OF GAS SLIPPAGE EFFECT IN COMPACT POROUS MEDIUM[J]. Journal of Geomechanics, 2018, 24(4): 498-504.

DOI10.12090/j.issn.1006-6616.2018.24.04.052     文章编号：1006-6616(2018)04-0498-07
RESEARCH PROGRESS OF GAS SLIPPAGE EFFECT IN COMPACT POROUS MEDIUM
RAN Yanxia , YE Bin , CHENG Zirui
College of Civil Engineering, Tongji University, Shanghai 200092, China
Abstract: The gas seepage in compact rock media is different from fluid seepage. The gas slippage effect is an important factor affecting gas flow in compact porous media. This paper summarizes the research progress on the gas slippage effect and synthetically analyzes the production mechanism and conditions of slippage effect, considering that the motion state of gas molecules near the pore wall contributes to the slippage effect of the gas. In addition, the effect of pore gas pressure, confining pressure, water saturation, gas properties, and other factors on the effect of gas slippage and its essence are studied and analyzed. It is of great reference for studying gas flow law in low permeability medium and measuring the gas permeability parameters in the development of low-permeability gas fields, etc.
Key words: compact rock media    gas seepage    slippage effect    low permeability medium    permeability
0 引言

1 气体滑脱效应产生的机理和条件 1.1 滑脱效应产生的机理

1.2 滑脱效应产生的条件

2 考虑气体滑脱效应的理论模型

 ${k_{\rm{g}}} = {k_\infty }(1 + b/{p_m})$ (1)

 $b = 4c\lambda {p_{\rm{m}}}/r \approx 4{p_{\rm{m}}}Kn$ (2)

λ为给定压力和温度下的气体分子平均自由程，nm；r为孔隙平均半径，nm；c为近似为1的比例常数。

 ${k_{\rm{g}}} = {k_\infty }\left( {1 + 4Kn} \right)$ (3)

 $q = f\left( {Kn} \right)\frac{{\pi {r^4}}}{{8\mu }}\frac{{\Delta p}}{l}$ (4)

 $f\left( {Kn} \right) = \left( {1 + \alpha Kn} \right)\left( {1 + \frac{{4Kn}}{{1 + Kn}}} \right)$ (5)

 $\alpha = \frac{{128}}{{15{\pi ^2}}}{\rm{ta}}{{\rm{n}}^{- 1}}[4.0K{n^{0.4}}]$ (6)

 ${k_{\rm{g}}} = {k_\infty }\left[{1 + {{\left( {\frac{b}{{{p_{\rm{m}}}}}} \right)}^2}\left( {\frac{{{L_{{\rm{ke}}}}}}{\lambda }} \right)} \right]$ (7)

3 气体滑脱效应的试验研究

3.1 不同致密储层中的滑脱效应 3.1.1 砂岩

 图 1 平均气体孔隙压力与渗透率关系[31] Figure 1 Relationship between average pore pressure and gas permeability[31]
3.1.2 煤层

3.1.3 其他储层

 图 2 流量与进出口压力平方差曲线[35] Figure 2 Curves of flow and outlet pressure squared difference[35]
3.2 滑脱效应的影响因素分析

4 结论

(1) 气体在致密岩石介质中低速渗流时，产生气体滑脱效应的实质是：气体分子的平均自由程接近孔隙孔径的尺寸时，孔隙壁面上各个气体分子都处于运动状态而速度不再为零，并且贡献一个附加流量，从而在宏观上表现为气体在孔隙壁面上具有非零速度，产生滑脱效应。当储层渗透率大于0.1×10-3 μm2时，气体滑脱效应可以忽略不计。