This experiment is conducted to evaluate effective porosity and water saturation

Abstract:
In
the previous two labs done by students, they will be able to observe the
porosity and water saturation of three Sandstone sample. Each sample has its
own diameter (mm), length (mm) and weight (g). Students were asked to determine
the porosity where it is defined as the percentage of pore volume within rock
than can be filled with fluid, water for example. The pores spaces are located
between grains and cracks in rocks. It is essential to know the porosity of a
rock, this is to know the capacity that the rock can contain fluids, by knowing
porosity, engineers will detect which rock is best to be contained with
hydrocarbons. Moreover, water saturation is the fraction of water in the pore
space corresponding to the effective porosity. It is calculated from the
effective porosity.

Introduction:
This
experiment has of two parts: (part 1) which is the spontaneous inhibition
method, and (part 2) the Desiccator method. In part (1), we observe the
porosity and water saturation. While in part (2), we measure the real
porosities for the samples. To find porosity, divide the pore volume (grain
volume) by the bulk volume (total volume). There are two types of porosity:
first is called total porosity, where it is the total void space in a rock over
bulk volume. Second type is called effective porosity; it is the interconnected
pore volume or void space in a rock that contributes to fluid flow or
permeability in a reservoir. An ideal porosity is ranged between 5-30%. By the
end of this experiment, students will be able to know types of porosity, how to
calculate real porosity, and calculate water saturation.

Discussion:
In
this lab, we record the porosity of three samples of sandstones. In the first
lab, we measured the weight of the three samples after wetting the samples in
water. Also we measured the dimensions of the samples so we can find the total
bulk volume. After that we put the three samples of sandstones in the oven for
about 24 hours to make them dry and measure the weight of the samples after we
dried them. Then we did calculations to find the porosity for each sample. We
noticed that one of the samples has the highest porosity due to the core of
this sample is able to take the highest amount of water. In the second lab we
compared the porosities of the three samples with the porosities of the same
samples when we put them in the water in a desiccator. The desiccator will
remove the air bubbles from the samples. The samples should be kept in the
desiccator for at least 3 to 4 hours until we make sure that all the air has
been removed from the samples. When we removed the samples from the desiccator
we noticed that the porosities have increased because the air was removed out
from the sandstones. As we noticed, when we measured the porosities of the samples
in the second lab they were higher than the porosities of the samples before we
put them in water in desiccator.

Conclusion:
The
more amount of water noticed in wetting the samples means the higher the
porosity is, this is because the porosity is the volume inside the rock that
can contain fluid, and so the volume of water represent the pore volume.
Moreover, It is concluded that the higher porosity in a source rock the more
favorable it isconsidered, because it is considered to be a source of hydrocarbon.
Furthermore, Porosity in the desiccator method (part 2) is much higher than
spontaneous inhibition method due to its accurate results obtained.