Laboratory Investigation Into the Formation and Dissociation Process of Gas Hydrate by Low‐Field NMR Technique

Abstract

We monitored the gas hydrate through low-field nuclear magnetic resonance measurement. An observed decrease of the relaxation time (T 2 ) intensity corresponds to the formation process, whereas an increase of the intensity corresponds to the dissociation process. The right domain of the spectrum with T 2 larger than 10 ms disappears gradually with the formation time, whereas the left domain with T 2 smaller than 1 ms remains invariant, indicating the gas hydrate forms preferentially in larger pores. In addition, the right domain increases rapidly with the dissociation time, revealing that the gas hydrate preferentially decomposes in large pores. The spectrum distributions move toward the fast relaxation domain with the growth of gas hydrate, because the generated gas hydrate occupies the large pore and accelerate the relaxation rate. There is no obvious relationship between the gas hydrate saturation and the porosity, whereas the volume and preliminary dissociation ratio are strongly correlated with the porosity.

Study on the Effects of Heterogeneous Distribution of Methane Hydrate on Permeability of Porous Media Using Low‐Field NMR Technique

“…They are effective methods to determine the water content in porous media using the cumulative amplitude of T 2 distribution (Ge et al, ; Kleinberg et al, ) and the signal intensity of magnetic resonance image (Wang et al, ; Zhao et al, ). In this study, both ends of the core sample were connect with bulk water during the permeability measurement.…”

“…They are effective methods to determine the water content in porous media using the cumulative amplitude of T 2 distribution (Ge et al, 2018;Kleinberg et al, 2003) and the signal intensity of magnetic resonance…”

A Practical Method to Compensate for the Effect of Echo Spacing on the Shale NMRT2Spectrum

“…To ensure most of the pores are occupied with the solution, the confining pressure and the saturating time are fixed as 30 MPa and 72 hr, respectively. To improve the SNR and the experiment efficiency, we used the benchtop of MesoMR23‐060H manufactured by Niumag Analytical Instrument Co., Ltd to perform the measurements (Ge et al, ; Su et al, ). The magnetic field strength of the device is 0.5 T. The T W and the NS are chosen as 3 s and 16, respectively.…”

“…Unfortunately, there are few proven methodologies to compensate for the effect caused by the T E . The best way to eliminate the effect is by reducing the instrument's intrinsic T E , which is feasible in laboratory investigation (Brizi et al, ; Dick et al, ; Ge et al, ; Menapace et al, ; Saidian, ; Sun, Yao, et al, ; Sun, Xiao, et al, ). However, reducing the T E of logging instruments are far more difficult due to the restraints of the electrical device and the apparatus structure.…”

Introduction to Special Issue on Gas Hydrate in Porous Media: Linking Laboratory and Field‐Scale Phenomena

“…Fine-grained particles that are mixed with coarser sediments can be mobilized under certain conditions and are also considered a component of pore fill in some cases. (2018) On the importance of advective versus diffusive transport in controlling the distribution of methane hydrate in heterogeneous marine sediments Lei and Santamarina (2018) Laboratory strategies for hydrate formation in fine-grained sediments (also fines) You and Flemings (2018) Methane hydrate formation in thick sandstones by free gas flow Effect of gas flow rate on hydrate formation within the hydrate stability zone Meyer, Flemings, DiCarlo, You, et al (2018) Experimental investigation of gas flow and hydrate formation within the hydrate stability zone Sahoo et al (2018) Presence and consequences of coexisting methane gas with hydrate under two phase water-hydrate stability conditions Almenningen et al (2018) Upscaled anisotropic methane hydrate critical state model for turbidite hydrate-bearing sediments at East Nankai Trough Ge et al (2018) Laboratory investigation into the formation and dissociation process of gas hydrate by low-field nuclear magnetic resonance technique Role of fines Han et al (2018) Depressurization-induced fines migration in sediments containing methane hydrate: X-Ray computed tomography imaging experiments Hyodo et al (2017) Influence of fines content on the mechanical behavior of methane hydrate-bearing sediments Jang et al (2018) Impact of pore fluid chemistry on fine-grained sediment fabric and compressibility Taleb et al (2018) Hydromechanical properties of gas hydrate-bearing fine sediments from in situ testing Geomechanical and hydraulic properties Spangenberg et al (2018) A quick look method to assess the dependencies of rock physical sediment properties on the saturation with pore-filling hydrate Madhusudhan et al (2019) The effects of hydrate on the strength and stiffness of some sands Kossel et al (2018) The dependence of water permeability in quartz sand on gas hydrate saturation in the pore space Gil et al (2019) Numerical analysis of dissociation behavior at critical gas hydrate saturation using depressurization method Cook and Waite (2018) Archie's saturation exponent for natural gas hydrate in coarse-grained reservoirs Zhou et al (2018) Upscaled anisotropic methane hydrate critical state model for turbidite hydrate-bearing sediments at East Nankai Trough Coupled numerical modeling Sánchez et al (2018) Coupled numerical modeling of gas hydrate-bearing sediments: From laboratory to field-scale analyses Kim et al (2018) Methane production from marine gas hydrate deposits in Korea: Thermal-hydraulic-mechanical simulation on production wellbore stabilit...…”