Rapid determination of fluid viscosity using low-field two-dimensional NMR

Area of Science:

• Petroleum Geosciences
• Analytical Chemistry
• Physical Chemistry

Background:

• Accurate fluid viscosity prediction is crucial for heavy-oil exploration and transportation.
• Traditional 2D NMR methods for viscosity prediction are time-consuming.

Purpose of the Study:

• To develop a rapid and accurate method for predicting fluid viscosity.
• To utilize 2D NMR relaxation time distributions for enhanced analysis.

Main Methods:

• Proposed a new pulse sequence: Driven-Equilibrium Fast-Inversion Recovery (DEFIR).
• DEFIR enables rapid measurement of 2D relaxation times using only two 1D measurements.
• Established a relationship between T1/T2 ratio, T1 distribution, and fluid viscosity via Bloembergen theory.

Main Results:

• DEFIR sequence is over 2 times faster than traditional 2D NMR methods.
• Developed a precise method for viscosity prediction based on NMR relaxation data.
• Successfully applied the method for on-site, on-line viscosity prediction in down-hole NMR fluid analysis systems.

Conclusions:

• The novel DEFIR-based method provides efficient and accurate fluid viscosity prediction.
• This technique enhances the capabilities of down-hole NMR fluid analysis.
• The method is particularly valuable for heavy-oil reservoir characterization.