川西蓬莱镇组致密砂岩毛管自吸水膜厚度变化与水锁关系实验

川西蓬莱镇组致密砂岩储层具有低孔、低渗特征,在开发过程中外来流体导致储层严重水锁损害。因此有必要对致密砂岩毛管自吸条件下不同含水率水膜厚度变化进行研究,为改善水锁损害方法的研究提供依据。利用毛管自吸法加工不同饱含水岩样,以氮气为流动介质,通过公式计算水膜厚度大小;并结合压汞实验数据,设计实验定量的分析水膜厚度差异与水锁关系。结果表明,岩石微观孔径主体分布为200 nm左右,毛管压力高,润湿相受毛管力作用表现为易进难出;当水膜厚度从10 nm增加到90 nm时,有效孔隙半径从100 nm减小到25 nm,氮气渗透率下降了95%。因此,认为通过对比水膜厚度与有效孔径大小可表征相应水锁损害程度,毛管自吸作用水膜厚度的增加导致致密砂岩气藏微观渗流能力下降,且随水膜厚度的不断增加水锁损害加剧。

The study in the relationship of tight sandstone wool tube water film thickness change and water blocking in western sichuan penglai town group

The tight sandstone reservoir of western Sichuan PengLai town has characteristics of low permeability reservoirs, There are serious water locking damage differences in the development process. So it is necessary for tight sandstone wool tube suction under the condition of different moisture content of the water film thickness changes, improve water locking damage. Using wool tube adsorption process with different water sample, with nitrogen as the flow medium, combined with the mercury injection experiment data, a quantitative analysis of design experiments of water film thickness difference, to study the relations of water film thickness and water lock. The results show that the rock micro aperture main distribution is about 200 nm, high capillary pressure, wetting phase by the capillary force is easy into difficult. When the water film thickness increased from 10 nm to 90 nm, the effective pore radius from 100 nm to 25 nm, nitrogen gas permeability decreased by 95. So that by comparing the water film thickness and the effective aperture size can represent the corresponding water lock damage, permeate sucking water film thickness increase led to the decrease of the tight sandstone gas reservoir microscopic percolation ability, and with the increasing water film thickness of water lock damage.