低速非达西流动机理分析

Analysis of low velocity non-Darcy flow mechanism

对低速非达西流动现象机理的解释历来有争议。近十余年我国学者对地下油气储集层中的非达西流动现象进行了较广泛的数学模拟和实验研究 ,大多相信与流体边界层性质异常有关。边界水曾被认为是在固体表面分子剩余力场作用下形成的一种晶体结构物质 ,但早在 2 0世纪 70年代 ,这种认识已被包括提出者在内的学者们否定 ,有关实验表明 ,边界水与本体水的黏度没有差别 ,不动层厚度仅为 1～ 2个水分子层厚度。根据近代表面与胶体化学原理指出 ,液体在储集层中的低速非达西流动不应归咎于流体边界层性质异常 ,而应归咎于岩石中胶体颗粒进入孔隙流体引起的塑性流动 ;气体在含水岩样中的低速非达西流动不应归咎于水膜 ,而应归咎于气体相渗透率滞后现象导致的水在岩样中的重新分布。

The low velocity non-D arcy flow mechanism is always a controversial subject. Over the past ten years, the Chinese researchers have made many extensive simulations and experimental st udies of this flow in oil and gas reservoirs, most of them believe that this phe nomenon is related to the anomalous boundary layers of the fluids. The boundary water was considered to be a crystalline substance formed by the action of the r emaining force field at the solid surface. But early in 1970s this viewpoint was refused by the researchers including the advocator. The surface force measureme nt shows that the viscosity of water adjacent to the silica surface is not diffe rent from the bulk water and at most 1-2 layers of water molecule are immobiliz ed at this solid surface. On the basis of recent surface and colloid chemistry t heory, it is held that the low velo city non-Darcy flow of the liquid in the reservoir rock could be attributed, no t to the anomalous boundary layers, as generally been assumed, but to the plasti c flow caused by the colloid substances in the reservoir rock entering into the fluid and also held that the low velocity non-Dary flow of the gas in watered r ock could be attributed,not to the water membrane,but to the redistribution of w ater in the rock resulted from the delay of the gas phase permeability.