Dynamic prediction of coalbed methane well considering pseudo-steady state diffusion
Dynamic prediction of coalbed methane well considering pseudo-steady state diffusion
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DOI：
10.1504/ijogct.2016.074767
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发表时间：
2016-02
期刊：
影响因子：
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通讯作者：
Fengpeng Lai;Zhiping Li;Y. Meng;Zhihao Yang;Zhen-zhen Guo;Hong Li
中科院分区：
文献类型：
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作者：
Fengpeng Lai;Zhiping Li;Y. Meng;Zhihao Yang;Zhen-zhen Guo;Hong Li
本研究建立了体积平衡和伪稳态扩散相结合的动态预测模型。体积平衡方程考虑了煤层、煤层气（CBM）和地层水，其中扩散发生在气体从基质系统移动到裂缝系统时。计算结果表明，扩散可以提高煤层气的最大产量。研究结果还表明，较大的扩散系数不仅可以提供更高的煤层气最大产量，而且可以提供更长的稳定生产时间。煤层气生产后期基质收缩效应越大，稳产时间越长，产量递减幅度越缓和。同时，产量达到最大值的时间也较短。储层渗透率越大，产量越高，稳产时间越短。渗透率对稳定生产时间的影响更为显着。
Dynamic prediction models combined with volume balance and pseudo-steady state diffusion were established in this study. Coal reservoir, coalbed methane (CBM), and formation water were taken into account in the volume balance equation, where the diffusion occurred as the gas travelled from the matrix system to the fracture system. Calculation results showed that diffusion could increase the maximum production of CBM. The findings also revealed that a larger diffusion coefficient would provide not only a higher maximum CBM production, but also a longer stable production time. Greater matrix shrinkage effect at the later stage of CBM production resulted in longer stable production time and gentler decline rate of production. Meanwhile, the time that production reached the maximum value was shorter. Also, the production was higher and the stable production time was shorter with greater reservoir permeability. Permeability had a more significant influence on stable production time.