Abstract

The complex pore structure of low‐permeability sandstone reservoir makes it difficult to characterize the heterogeneity of pore throat. Taking the reservoir of Sanjianfang formation in QL oilfield as an example, the fractal dimension of different storage spaces is calculated by using fractal theory based on casting thin section, scanning electron microscope, and high‐pressure mercury injection, and the correlation between porosity, permeability, and contribution of different storage space permeabilities is analyzed. The results show that the reservoir of Sanjianfang formation in QL oilfield mainly develops small pores, fine pores, and micropores, and the fractal dimension of micropore structure is between 2.6044 and 2.9982, with an average value of 2.8316. The more complex the pore structure is, the stronger the microheterogeneity is. The higher the fractal dimension, the more complex the pore structure and the smaller the porosity and permeability. The fractal dimensions of small pores, fine pores, and micropores increase successively with the decrease in pore radius, and the microstructure heterogeneity of large pores is weaker than that of small pores. It provides a theoretical basis for the exploration and development of low‐permeability sandstone reservoirs.

Highlights

  • Academic Editor: Xiaohu Zhang e complex pore structure of low-permeability sandstone reservoir makes it difficult to characterize the heterogeneity of pore throat

  • Taking the reservoir of Sanjianfang formation in QL oilfield as an example, the fractal dimension of different storage spaces is calculated by using fractal theory based on casting thin section, scanning electron microscope, and high-pressure mercury injection, and the correlation between porosity, permeability, and contribution of different storage space permeabilities is analyzed

  • By analyzing the relationship between the permeability contribution of pores at different scales and the fractal dimension (Figure 4), it can be found that the permeability contribution of small pores, fine pores, and micropores is positively correlated with the fractal dimension, and the correlation coefficient (R2) is 0.0051, 0.7291, and 0.4818, respectively. at is to say, the positive correlation between permeability contribution of fine pores and micropores and fractal dimension is better than that of small pores. e main reason may be that the dissolution pores and intercrystalline pores develop in the fine pores and micropores scale interval, whose irregular shape makes the heterogeneity of pore structure stronger but may form dominant channels that play a leading role in fluid flow and have good seepage characteristics

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Summary

Research Article

Fengjuan Dong ,1,2 Na Liu, Zhen Sun, Xiaolong Wei, Haonan Wang, Junxiang Nan, and Dazhong Ren. E complex pore structure of low-permeability sandstone reservoir makes it difficult to characterize the heterogeneity of pore throat. E fractal dimensions of small pores, fine pores, and micropores increase successively with the decrease in pore radius, and the microstructure heterogeneity of large pores is weaker than that of small pores It provides a theoretical basis for the exploration and development of low-permeability sandstone reservoirs. Taking the reservoir of Sanjianfang formation in QL oilfield as an example, the fractal dimension of different storage spaces is calculated by using fractal theory based on casting thin section, scanning electron microscope, and high-pressure mercury injection, and the correlation between porosity, permeability, and contribution of different storage space permeabilities is analyzed It provides theoretical basis for the exploration and development of low permeability sandstone reservoirs

Methods
Small pore Fine pore Micropore
Findings
Fractal dimension Fractal dimension
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