Relationship Between Throats Characteristics and Permeability in Tight Sandstone Based on Rate-controlled Mercury Injection - Example of Fuyu oil layer in Da'an area of Songliao Basin

摘要

There are a large number of throats in tight sandstone reservoir, the throat morphology is various and the distribution of throat radius is wide. These characteristics have great influence on the permeability of the tight sandstone reservoir. However, it has not been well studied. In this paper, we address this issue using a case study in the Da'an area of Songliao Basin, northeast China (Fuyu oil layer age, 2000-2500 m). Pores and throats dominate the properties of the reservoir. However, only the pores were the focus of previous studies. Thus, here we investigate the throats and its impacts on permeability, providing a complementary understanding of the microscopic characteristics in the tight sandstone reservoir. Using Rate-controlled Mercury Injection data of core samples, it was discovered that the throat radius of tight sandstone varies widely from 200 nm to 1100 nm, with an average of 580 nm. The rate-controlled mercury injection test results showed that the throat radius of the samples with different permeability was different. The size and number of the effective throat are the main controlling factors to increase the permeability of the reservoir.