The permeability of unconventional reservoirs is low

such as shale gas

coal-bed methane and tight gas. It is difficult to measure the permeability by the conventional method. Therefore

a method using the improved pressure depletion to measure the porosity and permeability of tight rock is proposed. The principle is to use a smaller volume gas container with a high pressure applied to one end of the rock sample and then record the process of pressure depletion. According to the variation of pressure with time

calculate the permeability and porosity of core. Therefore

the test principle is analyzed and the computational model for porosity and permeability is established

the pressure depletion rule of the typical compact shale rock samples is tested

and the effects of different factors（gas composition

temperature

confining pressure and displacement pressure） on pressure depletion and permeability are studied. The permeability values of a shale sample under different test conditions are calculated according to the experimental results. Permeability calculation results show that the permeability decreases with the increase of temperature or confining pressure

which prove that the temperature and confining pressure have important effects on permeability measurement results. Compared with the field test results

it is found that the permeability test results are consistent with it

indicating that the experimental method is reliable.