Limestone and dolomite reservoir rocks are by far the more important producers of oil and gas in Mexico compared to sandstone reservoirs. Many of the carbonate reservoirs are complex in that they display three types of pores: matrix porosity; vugs, and cavernous porosity; and fracture-induced porosity. This combination of three types of porosity can be described as “triple porosity.” Each pore type presents a different pore-throat size range and each has a different effect on permeability.

In order to better characterize these reservoirs, this paper proposes to visualize the relative abundance of each of these three pore types by plotting them on a triple-porosity pore-type ternary diagram (Fig. 1).

Figure 1.

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Triple-porosity pore-type ternary diagram showing comparisons with previous dual porosity methods. Also shown are areas on the diagram where the main facies of carbonate reservoirs in Mexico plot.

Figure 1.

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Triple-porosity pore-type ternary diagram showing comparisons with previous dual porosity methods. Also shown are areas on the diagram where the main facies of carbonate reservoirs in Mexico plot.