Fig 1.
The location map of structure zone in the study area.
Table 1.
Pore-throat structure parameters measured by HPMI.
Fig 2.
Triangular diagram of sandstone rock types of Eh3Ⅸ Formation in Anpeng area.
Fig 3.
The correlation chart of porosity and permeability of Eh3Ⅸ Formation.
Fig 4.
Microscopic characteristics of sandstones in Eh3Ⅸ Formation of Anpeng area.
(a) Residual intergranular pores and intergranular dissolved pores, flake or curved flake throat, S6, CTS; (b) Common feldspar dissolution pores and lithic dissolved pores, S8, CTS; (c) Feldspar dissolved pores and intergranular micropores, S14, CTS; (d) Intergranular pores and dissolved pores, flake or curved flake throat, S11, SEM; (e) Intergranular bridging illite, development of microcracks, S12, SEM. (f) Petal shaped chlorite adheres to the surface of particles, with enlarged authigenic quartz and the development of microcracks, S8, SEM.
Fig 5.
Mercury saturation curves, pore size distribution curves and Permeability contribution curves of Type Ⅰ (a, b, c), Ⅱ (d, e, f), and Ⅲ (g, h, i) samples obtained from HPMI test.
Fig 6.
Double logarithmic curves of the mercury inlet pressure (Pc) and the mercury inlet saturation (SHg) of the sandstone samples.
Table 2.
Fractal dimensions of pore-throat structure obtained from HPMI.
Fig 7.
Comparison of the effects of alkaline diagenesis and classical diagenesis on pores.
Fig 8.
Fractal characteristics of pore throats at different scales.
(a) The superposition diagram of Pittman curve and fractal curve of typical sandstone sample (S8); (b) The correlation between the turning point radius of fractal curves (rt) and the vertex radius of Pittman curves (rapex) of 14 sandstone samples.
Fig 9.
Binary pore structure model of tight sandstone.
Fig 10.
Relationship between different fractal dimensions (D1, D2, Da, and Dw) and reservoir physical properties, pore-throat structure, and reservoir quality parameters.
Fig 11.
Distribution characteristics of pore-throats of different scales.
(a-c) The distribution relationship between pore-throat size and mercury saturation and permeability contribution value for three types of typical sandstone samples (S8, S2, and S6) from type I to type Ⅲ; (d) Pore-throat volume distribution characteristics of sandstone samples at different scales.
Fig 12.
Permeability estimation model.
(a) Correlation between characteristic parameters and permeability; (b) The relationship between predicted permeability and measured permeability.
Table 3.
Permeability estimation models with different characteristic parameters.