砂岩输导层内天然气运移速率影响因素的实验研究

EXPERIMENT RESEARCH ON INFLUENCING FACTORS OF GAS MIGRATION RATE IN SANDSTONE CARRIER BEDS

采用岩心的砂岩微观模型进行气驱水运移实验,从实验观察和实验数据定量统计两个角度探讨了在岩心砂岩孔隙介质内影响天然气运移速率的主要因素。实验中发现,天然气在岩心砂岩孔隙介质内运移过程中,经常发生前缘跳跃和卡断—聚并现象,运移的速率是极不均一的,通过对这一现象的分析认为,砂岩孔隙结构特征、运移动力以及含气量是影响天然气渗流速率的主要因素。定量统计岩心砂岩的特征参数——渗透率、压力梯度、含气饱和度与平均运移速率的关系表明,天然气平均运移速率的大小与它们的综合效应成正比。

By using true sandstone micro-models, the experiment of gas driving water is performed to simulate the secondary migration in the sandstone carrier beds. The factors influencing the speed of gas migration are evaluated from two aspects, experiment phenomenon and quantitative statistical analysis in the true sandstone pore medium. It is found that the migration speed is inhomogeneous during the course of gas migration. The phenomena of frontal jump, snap-off and converging often occur. There are close relations between the gas osmosis speed, the quality of pore structures, migration force and the quantity of gas. The statistical analysis between the characteristic parameters of the influencing factors and the gas migration velocity shows that the mean flow speed of gas is in direct proportion to permeability, dynamic gradient and gas saturation.