Petrophysics

[1] Some fundamental petrophysical properties determined are lithology, porosity, water saturation, permeability, and capillary pressure.

[1] The petrophysicists workflow measures and evaluates these petrophysical properties through well-log interpretation (i.e. in-situ reservoir conditions) and core analysis in the laboratory.

During well perforation, different well-log tools are used to measure the petrophysical and mineralogical properties through radioactivity and seismic technologies in the borehole.

Petrophysics is part of the geosciences, and its studies are used by petroleum engineering, geology, geochemistry, exploration geophysics and others.

In the petroleum industry, rock samples are retrieved from the subsurface and measured by oil or service companies' core laboratories.

The electrolytes flowing inside the pore space within the water conduct electricity resulting in lower resistivity of the rock.

The fifth track shows the fraction of the total rock that is pore space filled with fluids (i.e. porosity).

The black line shows the fraction of the pore space, which contains either water or oil that can move or be "produced" (i.e. effective porosity).

While the magenta line indicates the toral porosity, meaning that it includes the water that is permanently bound to the rock.

The yellow pattern represents the fraction of the rock (excluding fluids) composed of coarser-grained sandstone.

Hence, a significant portion of clay minerals and silt-size particles results in a fine-grained sandstone with higher density and rock complexity.

As shown in Figure 2, for modelling clastic rock formation, there are four components whose definitions are typical for shaly or clayey sands that assume: the rock matrix (grains), clay portion that surrounds the grains, water, and hydrocarbons.

Due to the complex microstructure, for a water-wet rock, the following terms comprised a clastic reservoir formation: Vma = volume of matrix grains.