深盆气藏是一种特殊机理形成的具有气水倒置和负压异常等特征的致密气藏。储层致密是导致深盆气藏中气水倒置和负压异常的根本原因。在深盆气藏形成后 ,气藏内部任意一点的地层压力等于气水界面之上的静水柱压力与气藏内该点至气水界面处的气柱压力之和。由于气体的密度远小于水的密度 ,因此上述气水两段压力之和小于该两段都为静水柱时的压力之和 ,所以深盆气藏表现为负压异常。依据深盆气负压的特征及大小 ,可以判别含气层位的连通性、气柱高度和分布范围。在常规天然气成藏后 ,气藏内部任一点的地层压力等于气水界面之上的静水柱压力与气藏内该点至气水界面处的气柱压力之差。由于气体密度小于水的密度 ,气层内的压力比对应深度的静水柱压力大 ,因而常规气藏表现为超压异常。超压异常是常规气藏的一般特征 ,在一般地质条件下不能作为深盆气藏的判别标志。在几种特殊情况下 ,深盆气藏范围内也可以表现超压异常 Deep basin gas reservoirs are a kind of tight gas reservoirs with the characteristics of gas-water inversion and negative pressure anomalies formed by a special mechanism. The densification of reservoirs is the root cause of abnormal gas-water inversion and negative pressure in deep-basin gas reservoirs. After the deep basin gas pool is formed, the formation pressure at any point within the gas reservoir is equal to the sum of the hydrostatic pressure above the gas-water interface and the gas pressure at this point in the gas reservoir to the gas-water interface. Because the density of gas is far less than the density of water, the sum of the two pressures of gas and water is less than the sum of the pressures when the two sections are hydrostatic columns. Therefore, the deep basin gas reservoir shows negative pressure anomaly. Based on the characteristics and size of the deep basin gas negative pressure, connectivity of gas-bearing beds, gas column height and distribution range can be distinguished. After conventional natural gas accumulation, the formation pressure at any point inside the gas reservoir is equal to the difference between the hydrostatic pressure above the gas-water interface and the gas pressure at this point in the gas reservoir to the gas-water interface. As the gas density is less than the density of water, the pressure in the gas layer is larger than the hydrostatic pressure corresponding to the depth, so conventional gas reservoirs show overpressure anomalies. Overpressure anomalies are common features of conventional gas reservoirs and can not be used as discriminant markers for deep-basin gas reservoirs under general geological conditions. In several special cases, overpressure anomalies can also be expressed in the deep basin gas pool