What is intercrystalline porosity?

Intercrystalline Porosity. This type of porosity is formed in the existing space among the dolomite crystals (Figure 3(a)) and their geological origin is from sabkha to open marine. This porosity is one of the best spaces for gas reserves in the gas field.

What is good porosity in reservoir rock?

Commonly, permeability in the range of 100 to 500 md are reasonable values for a petroleum reservoir rock.

What is vuggy porosity?

Vuggy porosity is gas- or fluid-filled openings in rock matrix that are large enough to be seen with the unaided eye. Well-connected vugs can form major conduits for flow of ground water, especially in carbonate rocks.

What are the different classification of porosity?

Seven porosity types (interparticle, intraparticle, intercrystal, moldic, fenestral, fracture, and vugs) are common and volumetrically important.

What is Moldic porosity?

1. n. [Geology] A type of secondary porosity created through the dissolution of a preexisting constituent of a rock, such as a shell, rock fragment or grain. The pore space preserves the shape, or mold, of the dissolved material.

What is Fenestral porosity?

Fenestral porosity refers to penecontemporaneous or primary pores larger than the surrounding grain-supported fabric. Fenestral pores can develop in beach sands or carbonate muds as a result of air or gas bubbles in the sediment.

Which rock has the highest porosity?

Clay is the most porous sediment but is the least permeable. Clay usually acts as an aquitard, impeding the flow of water. Gravel and sand are both porous and permeable, making them good aquifer materials. Gravel has the highest permeability.

How do you determine porosity?

The first equation uses the total volume and the volume of the void. Porosity = (Volume of Voids / Total Volume) x 100%. The second equation uses the total volume and the volume of the solid. Porosity = ( ( Total Volume – Volume of the Solid ) / Total Volume ) x 100%.

How do you calculate porosity?

What is intragranular porosity?

(viii) Intragranular porosity The porosity due to voids within the rock grains. (ix) Dissolution porosity The porosity resulting from dissolution of rock grains. (x) Fracture porosity The porosity resulting from fractures in the rock at all scales.

What is fabric selective porosity?

If a dependent relationship exists between porosity and particular fabric elements, that porosity is referred to as fabric-selective, which can be primary or secondary (Figure 2). If no relationship between fabric and porosity can be established, the porosity is classed as not fabric-selective.