The tight-sandstone gas reservoir in Zhongba gas field is a fracture-pore type reservoir controlled by structures and fractures. On the basis of analyzing the basic characteristics of reservoirs

the factors controlling the fractures are discussed to figure out the effect of fractures distribution on the formations and predict the distribution of residual gas. The reservoir is mainly composed of light gray-gray fine-medium lithic feldspar quartz sandstone with its average porosity and permeability being 6.29 % and 0.19×10

-3

μm

2

respectively. It belongs to low porosity and permeability formations. And based on this

the fracture was studied by means of tectonic curva

ture method and rock mechanics experiment. The results showed that the fractures on the surface were mainly developed along the structural axis and close to the southeast arc and the northern conjunction of the saddle. The developments of fractures were tightly related with lithology. Combined with the numerical simulation results of gas reservoir

the potentials of the gas reservoir are analyzed to support the scheme adjustment in the next stage of development.