何岩峰,赵虹宇,窦祥骥,王相,徐慧
HE Yanfeng,ZHAO Hongyu,DOU Xiangji,WANG Xiang,XU Hui

• 1:常州大学石油工程学院

摘要(Abstract)：

页岩储层纳米孔隙中气体传输模型是页岩气开发的研究重点之一。现有的页岩气表观渗透率计算模型通常假设页岩气为理想状态,而未考虑真实气体密度和应力敏感的影响,且应力敏感模型大多通过实验数据拟合的经验公式进行计算,适用范围有限。为了建立更加准确的页岩气表观渗透率模型,着重考虑了应力敏感影响下孔隙压力与半径的相互影响以及页岩基质中气体的滑移流动和过渡扩散,并通过修正的Soave-Redlich-Kwong(SRK)状态方程,计算出页岩气的密度。研究认为:随着页岩气开采的进行,有效应力增大,纳米孔隙半径随孔隙压力的降低而减小;页岩纳米孔隙渗透率随着孔隙压力的降低而减小,且孔隙半径越大,渗透率下降的幅度越大;页岩储层本身性质对纳米孔的半径有影响,在相同孔隙半径条件下,弹性模量越小,纳米孔半径受有效应力影响越大,即孔径缩小的幅度越大,页岩气开采难度越大。模型计算结果与实验数据进行对比表明,新计算模型可靠。
The gas transporting model in the nano-pores of shale reservoirs is one of the important research focuses.The existing shale-gas apparent permeability model assumes that the gas is ideal gas and does not consider the impacts of the real gas density and stress sensitivity,and moreover most of the stress-sensitive models are calculated by the empirical formula fitted by the experimental data,and furthermore the applied range is rather limited. In order to build more accurate model for the shale-gas apparent permeability,the mutual influence between the pore pressure and radius and moreover the slip flow and transition diffusion of the gas in the shale matrix were emphatically considered,besides,with the help of the modified SRK( Soave-Redlich-Kwong) equation of the state,the shale gas density was calculated. The study shows that with the production of the shale,the effective stress increases,with the decrease of the pore pressure,the nano-pore radius decreases as well,so does the nano-pore permea-bility,the bigger the pore radius is,the greater decline will be for the permeability; the itself properties of the shale reservoir possess the influences on the nano-pore radius,under the same pore radius condition,the smaller the elastic modulus is,the greater impact of the effective stress will have on the nanopore radius i. e. the larger the pore radius reduced,the more difficult will be for the shale gas production. The contrast between the model calculated results and experimental data shows that the new calculating model is reliable.

关键词(KeyWords)： 页岩储层;纳米孔隙;应力敏感;渗透率;页岩气密度
shale reservoir;nano-pore;stress sensitivity;permeability;shale gas density

Abstract:

Keywords:

基金项目(Foundation): 江苏省高等学校自然科学研究项目“基于无梯度多级进化算法的页岩气藏生产智能优化方法”(17KJB440001)

作者(Author): 何岩峰,赵虹宇,窦祥骥,王相,徐慧
HE Yanfeng,ZHAO Hongyu,DOU Xiangji,WANG Xiang,XU Hui

DOI: 10.19597/J.ISSN.1000-3754.201808013

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