# What is the absolute porosity?

## What is the absolute porosity?

The absolute porosity is defined as the ratio of the total pore space in the rock to that of the bulk volume. A rock may have considerable absolute porosity and yet have no conductivity to fluid for lack of pore interconnection.

## What is effective porosity and total porosity?

Effective porosity is that portion of the total void space of a porous material that is capable of transmitting a fluid. Total porosity is the ratio of the total void volume to the total bulk volume. Porosity ratios traditionally are multiplied by 100 and expressed as a percent.

**How do you determine effective porosity?**

In essence, total porosity minus shale water, where solid minerals and the volume of shale (Vsh) constitute the matrix (non-effective porosity) and the remaining volume constitutes the effective porosity.

**What are the three types of porosity?**

There are three levels of porosity: low, medium, and high.

### Why is effective porosity less than the total porosity?

Effective porosity is typically less than total porosity. In the original definition of core analysts, the volume of connected pores in a unit volume of rock. The definition is based on the analysis of shaly formations, in which the clay-bound water is considered immobile and hence ineffective.

### What is absolute porosity in petroleum engineering?

Absolute porosity: It is a ratio of total pore space to a rock bulk volume. This will not account for voids which don’t connect to others. Effective porosity: It is a ration of interconnected pore spaces to a rock bulk volume. This is a proper figure to use to calculate fluid volume in a reservoir.

**What is the difference between effective porosity and permeability?**

Effective porosity is the space available for fluid to flow, and is calculated as the volume of interconnected void space to the total volume, typically given as a percentage. Porosity can be deemed either primary or secondary….Porosity and Permeability.

Rocks | Porosity (%) |
---|---|

Silt | 0.35 – 0.50 |

Clay | 0.40 – 0.70 |

**Is core porosity total or effective?**

9.4 Comparison of Log and Core Porosity. Core porosity is usually an accurate measure of local porosity because the porosity is measured directly.

## Why is effective porosity less than total porosity?

## Which material 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.

**What is effective permeability?**

1. n. [Geology] The ability to preferentially flow or transmit a particular fluid when other immiscible fluids are present in the reservoir (e.g., effective permeability of gas in a gas-water reservoir).

**What is secondary porosity?**

Primary porosity is the original porosity of the rock when it formed, and secondary porosity is the pore space created by subsequent processes such as fracturing.

### What is the formula for calculating porosity?

If you want to calculate porosity theoretically in a given problem, use the equation porosity = pore volume ÷ total volume . Before inserting your values, make sure the units of measurement match because porosity is expressed as a percentage.

### Is porosity always less than the void ratio?

Porosity is the percentage of void space in a rock. Porosity is the percentage of void space in a rock. It is defined as the ratio of the volume of the voids or pore space divided by the total volume. It is written as either a decimal fraction between 0 and 1 or as a percentage. For most rocks, porosity varies from less than 1% to 40% .

**What factors determine porosity?**

Factors affecting porosity. The most obvious factor is rock type. Crystalline igneous and metamorphic rocks have virtually no porosity. The porosity of sedimentary rocks varies according to: The degree of sorting. The amount of Diagenesis the rock has undergone. Grain shape. Packing of the grains.

**What is the difference between porosity and voids?**

As nouns the difference between porosity and void is that porosity is (uncountable) the state of being porous while void is an empty space; a vacuum or void can be . As an adjective void is containing nothing; empty; vacant; not occupied; not filled. As a verb void is (label) to make invalid or worthless.