Application of binomial-edited CPMG to shale characterization.

Area of Science:

• Geochemistry
• Petroleum Geology
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Unconventional shale resources contain significant hydrogen within organic solids like kerogen.
• Direct detection of these organic solids is challenging with conventional Nuclear Magnetic Resonance (NMR) systems.
• Understanding the distribution and type of organic matter is key to resource evaluation.

Purpose of the Study:

• To present binomial-edited NMR as an indirect detection method for solid organic materials in shales.
• To evaluate the effectiveness of binomial-editing in distinguishing different phases within shale samples.
• To assess the potential of binomial-editing for characterizing fluid locations and organic content.

Main Methods:

• Application of a binomial-edited Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence.
• Analysis of various natural and experimentally altered shale samples.
• Monitoring signal loss to infer the presence and abundance of organic solids.

Main Results:

• Shale samples rich in organic solids exhibited substantial signal loss when analyzed with binomial-editing.
• Fluids residing in inorganic pores showed minimal signal alteration, indicating phase specificity.
• The technique successfully differentiated between organic solid phases.

Conclusions:

• Binomial-editing offers a viable indirect method for detecting solid organic matter in shales.
• This NMR approach can determine fluid locations and quantify solid organic content.
• The technique shows promise for kerogen-bitumen discrimination in unconventional resources.