关键词: 渗透率, 含水饱和度, 封闭压力, 致密砂岩气藏, 孔隙度, 致密气藏, 地质特征, 岩性圈闭, 致密储层, 渗透性

Abstract: As compared to conventional sandy gas reservoir, the water saturation of a tight sandy gas reservoir has a higher effect on its identification in addition to its lower permeability. Moreover, no linear relationship is found to be existed between its porosity and permeability and confining pressure has a much more effect than that in the case of a conventional reservoir. The major parameter used in the classification of a tight gas reservoir for its evaluation is subsurface permeability, and porosity comes to the next, The major geological features are: (1) It is located usually in the centre of a sag in the sedimentary basin or on the slop of a transitional zone; (2) It is a lithologic trap usually; (3) It has a high gas column and with pay zones distribution in a fairly long interval; (4) It is usually abnormally high pressure. Large deltaic sand bodies should be taken as a major target for exploration with a depth of burial of <4000m, and attention should be paid to the parameter, water saturation.