10,323
edits
Changes
Jump to navigation
Jump to search
Line 46:
Line 46: − + + + + Line 52:
Line 55: − − [[file:predicting-reservoir-system-quality-and-performance_fig9-28.png|300px|thumb|{{figure number|3}}Relative permeability relationships for rock with different pore types.]]
no edit summary
==Pore throat size and k<sub>r</sub>==
==Pore throat size and k<sub>r</sub>==
Every pore type has a unique relative permeability signature. Consider the hypothetical drainage relative permeability type curves shown below. Curves A, B, and C represent the relative permeability relationships for rocks with different port types: macro, meso, and micro, respectively. Curve A represents a rock with greater performance capability than B or C. Note how critical water saturation decreases as pore throat size increases. Also note the changing position of K<sub>ro</sub>–K<sub>rw</sub> crossover with changes in pore throat size.
[[file:predicting-reservoir-system-quality-and-performance_fig9-28.png|300px|thumb|{{figure number|3}}Relative permeability relationships for rock with different pore types.]]
Every pore type has a unique relative permeability signature. Consider the hypothetical drainage relative permeability type curves shown in [[:file:predicting-reservoir-system-quality-and-performance_fig9-28.png|Figure 3]]. Curves A, B, and C represent the relative permeability relationships for rocks with different port types: macro, meso, and micro, respectively. Curve A represents a rock with greater performance capability than B or C. Note how critical water saturation decreases as pore throat size increases. Also note the changing position of K<sub>ro</sub>–K<sub>rw</sub> crossover with changes in pore throat size.
==Critical water saturation==
==Critical water saturation==
==Critical water saturation==
==Critical water saturation==
The critical S<sub>w</sub> value is different for each port type. Curve A in Figure 9-28 represents rocks with macroporosity. It has a critical S<sub>w</sub> less than 20%. Curve B represents a rock (continued) with mesoporosity. Mesoporous rocks have a critical S<sub>w</sub> of 20–60%. Curve C represents rocks with microporosity. They have a critical S<sub>w</sub> of 60–80%.
The critical S<sub>w</sub> value is different for each port type. Curve A in Figure 9-28 represents rocks with macroporosity. It has a critical S<sub>w</sub> less than 20%. Curve B represents a rock (continued) with mesoporosity. Mesoporous rocks have a critical S<sub>w</sub> of 20–60%. Curve C represents rocks with microporosity. They have a critical S<sub>w</sub> of 60–80%.