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微纳米孔隙页岩气藏的运移机制主要包括黏性流、Knudsen扩散、分子扩散及表面扩散,在其表观渗透率计算模型研究过程中,逐渐形成了Civan模型、Florence模型、Javadpour模型、郭超华模型、Xiong X模型、分形模型、有机质与无机质模型以及吴克柳模型等。研究结果表明,表观渗透率计算模型早期仅考虑游离气运移机制,后来全面考虑各种运移机制。随着研究的深入,孔隙结构更加符合微纳米孔隙实际情况,动力学模型更加符合页岩实际运移规律,表观渗透率计算模型向精细化、实际化方向发展。通过实例计算分析可得,不同表观渗透率计算模型计算结果略有差别,但都在误差允许范围内;在相同压力下,考虑表面扩散运移机制的计算模型所得到的表观渗透率值大于不考虑表面扩散运移机制模型计算得到的表观渗透率值。另外,页岩气藏的表观渗透率随有效压力的增大逐渐减小,在压力较低时,表观渗透率随有效压力增大下降较快,压力较高时,表观渗透率值趋于平稳。
The transport mechanism of micro-nano porosimeter shale gas reservoirs mainly includes viscous flow, Knudsen diffusion, molecular diffusion and surface diffusion. Civan model, Florence model, Javadpour model are gradually formed in the study of its apparent permeability calculation model. Guo Chaowei model, Xiong X model, fractal model, organic matter and inorganic model and Wu Keli model. The results show that the apparent permeability calculation model only considers the free gas migration mechanism in the early stage and later fully considers various migration mechanisms. With the deepening of the research, the pore structure is more in line with the actual situation of micro-nano pores, the dynamic model more in line with the actual migration of shale, apparent permeability model to fine and practical direction. Through the calculation and analysis of the examples, it can be seen that the calculation results of the different apparent permeability models are slightly different but within the allowable range of error. Under the same pressure, the apparent permeability value obtained by the calculation model of surface diffusion and transport mechanism Which is larger than the apparent permeability calculated without considering the surface diffusion mechanism model. In addition, the apparent permeability of shale gas reservoir decreases with the increase of effective pressure. When the pressure is low, the apparent permeability decreases rapidly with the increase of effective pressure. When the pressure is higher, the apparent permeability Towards stability.