DOI: 10.5061/dryad.6t1g1jxbj
title: Data from: Characterization of fluid occurrence states in Shale reservoirs: Centrifugal-nuclear magnetic resonance experimental analysis

description: The occurrence states of fluids in shale reservoirs directly influence the
 resource assessment of shale gas, reservoir permeability, selection of
 development technologies, and economic benefits. Accurate analysis of
 fluid occurrence states is a key foundation for the efficient exploration
 and development of shale gas. To comprehensively elucidate the fluid
 distribution characteristics within shale pores, this study integrates
 centrifugation-nuclear magnetic resonance (NMR) experiments with stepwise
 thermal drying and methane adsorption analyses. By examining the NMR T₂
 spectra of shale samples under varying centrifugal speeds, the distinction
 between movable and bound fluids is established, clarifying the influence
 of pore structure on fluid occurrence. Quantitative relationships between
 pore size and adsorbed/free gas are further investigated through methane
 adsorption experiments. Results demonstrate that centrifugation
 progressively removes water from macropores and microfractures, leaving
 residual water mainly confined to micropores. The stepwise thermal drying
 method efficiently differentiates movable water, capillary-bound water,
 and clay-bound water. Integrating NMR analysis with methane adsorption
 reveals a significant impact of pore size on fluid occurrence: micropores
 predominantly store adsorbed gas, whereas macropores mainly contain free
 gas. These findings provide a theoretical basis for shale gas development
 and furnish essential data for optimizing exploration and production
 techniques.
description: # Data from: Characterization of fluid occurrence states in Shale
 reservoirs: Centrifugal-nuclear magnetic resonance experimental analysis
 Dataset DOI: [10.5061/dryad.6t1g1jxbj](10.5061/dryad.6t1g1jxbj) ##
 Description of the data and file structure This document provides detailed
 information about the raw data underlying Figure 1 to 5 from the study
 *"Characterization of Fluid Occurrence States in Shale Reservoirs:
 Centrifugal-Nuclear Magnetic Resonance Experimental Analysis"*. The
 data is derived from experimental analyses, including centrifugation-NMR,
 porosity measurements, and methane adsorption tests on shale samples. All
 data is structured to support reproducibility and further research. The
 experimental principles and detailed operational procedures have been
 comprehensively described in the article. This document solely contains
 the experimental data for verification of results or direct use by all
 parties. ### Files and variables #### File: Raw_data.opju
 **Description:** The subfolder "Folder1" under
 "Raw_data" contains Figure 1, 2, 3, 4, 5, and 6. **Figure 1: NMR
 T2 Spectra of Saturated Water and Centrifugal Experiments** Figure 1
 illustrates the evolution of NMR T2 spectra for four shale samples under
 water-saturated conditions and varying centrifugal speeds (4000–12000
 rpm). Figure 1 includes 1a, 1b, 1c, 1d.  The x-axis represents the nuclear
 magnetic resonance T2 spectrum (ms), with data in log10 scale. The y-axis
 represents the signal intensity (au), with data in linear scale. It also
 includes the description of each set of data (Water saturation, The speed
 of the centrifuge). **Figure 2: Changes in NMR Porosity at Different
 Centrifugal Speeds** Figure 2 shows NMR-derived porosity changes for shale
 samples across centrifugal speeds. Figure 2 includes Sheet1.  The x-axis
 represents the Centrifugation rate (rpm). The y-axis represents the
 Magnetic porosity (%). It also includes the description of each set of
 data (Sample Number). **Figure 3: NMR T2 Spectra After Centrifugal
 Experiments** ​Figure 3 compares NMR T2 spectra for core plugs and crushed
 samples after centrifugation, emphasizing pore-type effects. Figure 3
 includes 3a, 3b, 3c, 3d, 3e, 3f.  The x-axis represents the nuclear
 magnetic resonance T2 spectrum (ms), with data in log10 scale. The y-axis
 represents the signal intensity (au), with data in linear scale. It also
 includes the description of each set of data (The speed of the
 centrifuge). **Figure 4: Methane Adsorption NMR T2 Spectra** ​Figure 4
 displays NMR T2 spectra for methane adsorption under pressures (2.80–14.62
 MPa), featuring a three-peak distribution. Figure 4 includes 4a, 4b, 4c,
 4d.  The x-axis represents the nuclear magnetic resonance T2 spectrum
 (ms), with data in log10 scale. The y-axis represents the signal intensity
 (au), with data in linear scale. It also includes the description of each
 set of data (Pressure values). **Figure 5: Methane Mass vs. Pressure
 Relationship** ​Figure 5 quantifies methane mass per peak vs. pressure,
 revealing occurrence states. Figure 5 includes 5-1, 5-2, 5-3. The x-axis
 represents the Pressure (Mpa), with data in linear scale. The y-axis
 represents the First peak methane mass (g), with data in linear scale.
 **Figure 6: Relationship between pore volume and NMR signal intensity for
 each peak in the methane adsorption T2 spectra after fractal analysis**
 Figure 6 shows the correlation analysis between the porosity contributions
 of various pore types and the NMR signal intensities of each peak in
 methane adsorption T₂ spectra. Figure 6 includes 6-1, 6-2, 6-3. The x-axis
 represents the Micro-pore porosity (%), with data in linear scale. The
 y-axis represents the First peak area semaphore (au), with data in linear
 scale. ## Code/software The file can be viewed using Origin software (any
 version). [OriginLab - Origin and OriginPro - Data Analysis and Graphing
 Software](https://www.originlab.com/) ## Access information Other publicly
 accessible locations of the data: * NA Data was derived from the following
 sources: * NA