Question:
Which of the following is/are obtained using a core sample?
Which of the following is/are obtained using a core sample?
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A core plug is lab tested for porosity, pore size distribution and permeability, but it is too small to reveal reservoir extent.
Updated On: Aug 17, 2026
- Porosity
- Pore size distributions
- Absolute permeability
- Reservoir boundary
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Verified By Collegedunia
The Correct Option is A, B, C
Solution and Explanation
Step 1: Understand what core analysis provides:
A core sample is a physical plug of rock cut from the wellbore and taken to a laboratory, where routine core analysis and special core analysis tests are run directly on that small piece of rock. These tests give the actual measured rock properties at the sample scale, unlike logs or well tests which estimate properties indirectly over a larger volume.
Step 2: Check option A, porosity:
Porosity is measured directly on a core plug using techniques such as helium porosimetry or fluid saturation methods, which find the void volume as a fraction of the bulk volume of the plug. This is one of the most basic and standard outputs of routine core analysis, so option A is correct.
Step 3: Check option B, pore size distributions:
Pore size distribution is obtained through special core analysis, most commonly mercury injection capillary pressure testing, where mercury is forced into the pore network of the plug under increasing pressure and the pressure at which mercury enters pores of a given size is recorded. This gives a detailed picture of how pore sizes are distributed within the sample, so option B is correct.
Step 4: Check option C, absolute permeability:
Absolute permeability is measured on a core plug by flowing a single phase fluid, usually gas or brine, through the fully saturated sample and applying Darcy's law to the measured flow rate and pressure drop. This laboratory permeameter test is a standard part of routine core analysis, so option C is correct.
Step 5: Check option D, reservoir boundary:
A core plug is only a few centimeters in size and represents conditions at one depth in one well. It cannot reveal the areal extent, shape, or sealing behavior of the reservoir as a whole. Reservoir boundaries are instead inferred from seismic surveys, well test pressure transient analysis, and correlation of multiple wells, so option D is not correct.
Final Answer:
\[ \boxed{\text{Porosity, pore size distribution and absolute permeability, options A, B and C}} \]
A core sample is a physical plug of rock cut from the wellbore and taken to a laboratory, where routine core analysis and special core analysis tests are run directly on that small piece of rock. These tests give the actual measured rock properties at the sample scale, unlike logs or well tests which estimate properties indirectly over a larger volume.
Step 2: Check option A, porosity:
Porosity is measured directly on a core plug using techniques such as helium porosimetry or fluid saturation methods, which find the void volume as a fraction of the bulk volume of the plug. This is one of the most basic and standard outputs of routine core analysis, so option A is correct.
Step 3: Check option B, pore size distributions:
Pore size distribution is obtained through special core analysis, most commonly mercury injection capillary pressure testing, where mercury is forced into the pore network of the plug under increasing pressure and the pressure at which mercury enters pores of a given size is recorded. This gives a detailed picture of how pore sizes are distributed within the sample, so option B is correct.
Step 4: Check option C, absolute permeability:
Absolute permeability is measured on a core plug by flowing a single phase fluid, usually gas or brine, through the fully saturated sample and applying Darcy's law to the measured flow rate and pressure drop. This laboratory permeameter test is a standard part of routine core analysis, so option C is correct.
Step 5: Check option D, reservoir boundary:
A core plug is only a few centimeters in size and represents conditions at one depth in one well. It cannot reveal the areal extent, shape, or sealing behavior of the reservoir as a whole. Reservoir boundaries are instead inferred from seismic surveys, well test pressure transient analysis, and correlation of multiple wells, so option D is not correct.
Final Answer:
\[ \boxed{\text{Porosity, pore size distribution and absolute permeability, options A, B and C}} \]
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