The Upper Paleozoic reservoirs were of low permeability and a gently west-dipping slope in the Ordos Basin, and the gas field being deep basin gas trap. The meteoric water flowed, induced by gravity, from the northern and eastern basin edges into the interior, but the gas flowed from the west to the east, some of which would escape upwards, making up the present kinetic models of underground fluids.With the buried depth increasing, gas and mudstone-compacted water permeated the reservoirs, resulted in high abnormal fluids pressures, and gas could dissolute into formation water. As the gas concentration increased, or bed erosion or buried depth decreased during formation water flowing, fluid pressures decreased. The gas was freed from water and the deep basin gas field created, some of them escaped upwards along the formation water flow directions, which was a typical characteristics of deep basin gas field. Due to low permeability, the recharge of formation water could be very slowly, and gas escaping could induce low abnormal fluid pressures. In the meantime, the gas flow could migrate slowly since its low permeability, and the deep basin gas field could be preserved.