Reservoir Evaluation and Development ›› 2020, Vol. 10 ›› Issue (1): 49-55.doi: 10.13809/j.cnki.cn32-1825/te.2020.01.008

• Method and Theory • Previous Articles     Next Articles

Improved pressure depletion method measure the porosity and permeability of shale

REN Jianhua1,LU Bi1,REN Shaoran2   

  1. 1. Research Institute of Exploration and Development, Sinopec East China Oil and Gas Company, Nanjing, Jiangsu 210011, China
    2. School of Petroleum Engineering, China University of Petroleum(East China), Qingdao, Shandong 266580, China
  • Received:2019-06-17 Online:2020-02-26 Published:2020-02-04

Abstract:

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.

Key words: tight rock, permeability, porosity, pressure depletion method, influencing factors

CLC Number: 

  • TE122