Two-dimensional nuclear magnetic resonance petrophysics

Area of Science:

• Petrophysics
• Geophysics
• Analytical Chemistry

Background:

• Nuclear Magnetic Resonance (NMR) is crucial for characterizing porous media.
• Distinguishing between multiple fluid types (e.g., oil and water) in rocks is essential for petroleum exploration.
• Traditional NMR methods can struggle to differentiate fluids with similar properties.

Purpose of the Study:

• To explore the application of two-dimensional nuclear magnetic resonance (2D NMR) in petrophysics.
• To demonstrate the impact of 2D NMR on petroleum logging technology.
• To delineate and extract information from multiple fluids with different diffusion coefficients in porous media.

Main Methods:

• Utilizing Carr-Purcell-Meiboom-Gill (CPMG) measurements.
• Employing regular pulsing sequences and modified two-window sequences.
• Analyzing data using a 2D NMR plot with T2 relaxation time and diffusion coefficient as independent variables.

Main Results:

• Clear separation of oil and water signals in rocks was achieved.
• The 2D NMR approach successfully delineated fluids based on their diffusion coefficients.
• The method proved effective for systems with multiple fluids having distinct diffusion properties.

Conclusions:

• 2D NMR is a powerful tool for petrophysical analysis and petroleum logging.
• The combination of T2 relaxation time and diffusion coefficient in 2D NMR enables precise fluid identification.
• This 2D NMR concept is extendable to other fluid-saturated porous media studies with different variable combinations.