Study on porosity of low-permeability rocks collected from F₄ fault zone in Gansu Beishan region based on digital image analysis

As a research object of this plan, Xinchang area is one of the candidate areas in Gansu Beishan region, Gansu province which is preselected to be the area for China's high-level radioactive waste repository. Through the field investigation and sample collection, on the base of rock pretreatment, a complete set of system approach based on digital image technology have been set up in order to extract rock pore parameters, the extraction and statistics of rock samples in F₄ fault zone were also acquired in this experiment. Meanwhile, digital image processing technique was put into use. Areal porosity data and mineral composition in S₁, S₂ and S₃ were obtained through taking method of digital image processing which had great contribution to acquire hydrogeological data from this fault zone. (authors)