Petrophysical and geochemical evaluation of shales using magnetic resonance T1-T2∗ relaxation correlation. (15th January 2021)

• Record Type: Journal Article
• Authors: Zamiri, Mohammad Sadegh; MacMillan, Bryce; Marica, Florea; Guo, Jiangfeng; Romero-Zerón, Laura; Balcom, Bruce J.
• Is Part Of: Fuel. Volume 284(2021)
• Publication Date: 2021-01-15
• Subjects: Oil shale -- Magnetic resonance relaxation -- Fluid content -- Kerogen content -- 2D relaxation correlation maps -- Water sorption; MR magnetic resonance -- RF radio frequency -- CPMG Carr-Purcell-Meiboom-Gill -- FID free induction decay -- RH relative humidity -- TOC total organic carbon -- API American Petroleum Institute; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.119014
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: New insight in magnetic resonance relaxation mechanisms of 1 H -bearing compounds in shales. A novel 2D magnetic resonance T 1 - T 2 ∗ technique is introduced for shale fluid typing. T 1 - T 2 ∗ capability in quantifying water in adsorption/desorption process is studied. A procedure is provided to quantify shale fluid content based on the T 1 - T 2 ∗ technique. T 1 - T 2 ∗ technique provides quantitative 1 H content of kerogen allowing geochemical studies. Abstract: Quantification of fluid and organic matter content of shale samples are principal goals of petrophysical and geochemical evaluation of shales that are essential to determine reservoir quality. While volumetric methods to characterize shales are cumbersome and destructive, 1 H magnetic resonance (MR) methods are robust, fast, and non-destructive. However, short-lived MR signal lifetimes of shale samples challenge existing MR methods and motivate the development of new MR methods. Two-dimensional (2D) MR T 1 - T 2 relaxation correlation is a powerful method to differentiate hydrogen-bearing species in porous materials. However, the experimental echo time limitation of the T 1 - T 2 method precludes acquisition of important short lifetime signal components. In addition, due to overlap of signal components in T 1 - T 2 correlations, quantification accuracy is impaired in shales. Here, we introduce the 2D MR T 1 - T 2 ∗ relaxation correlation measurement for quantitative determination of shale 1 H components. Liquid-rich shale samples from the Eagle Ford Formation were used in adsorption/desorption and evaporation experiments. 2D MR T 1 - T 2 and T 1 - T 2 ∗ correlations coupled with gravimetric measurements were performed to identify water, oil/bitumen, and kerogen peaks in the relaxation correlation maps. Peaks associated with shale components showed significant contrast in T 1 - T 2 ∗ correlations. This allowed quantitative measurement of water and oil content using the signal intensity of each peak.