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How do petroleum geologists use core samples to evaluate an oil reservoir?
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petroleum production
A semisubmersible oil production platform operating in water 1,800 metres (6,000 feet) deep in the Campos basin, off the coast of Rio de Janeiro state, Brazil.
Petroleum geologists use core samples—cylindrical pieces of subsurface material extracted during drilling—to gain a direct, visual record of the rock formations encountered. By examining these samples, geologists can evaluate an oil reservoir in several critical ways:12
- Physical Properties: Core analysis allows for the direct measurement of porosity (the volume of pore space in the rock) and permeability (the rock's ability to transmit fluids), which are essential for determining how easily oil can be recovered.23
- Reservoir Geometry: Geologists use the samples to determine the depth and thickness of the reservoir rock.3
- Geologic Interpretation: The core provides a physical basis for creating a log, which serves as the fundamental data for geologic analysis and resource calculations.1
- Comparative Analysis: Samples allow geologists to investigate specific features of a strata and compare them with known oil- or gas-bearing zones.2
This information is vital for estimating the total quantity of oil present and assessing the economic viability of the reservoir.3