scholarly journals Experimental Study on Mechanical Properties of Hydrate-Bearing Sand: The Influence of Sand-Water Mixing Methods

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2554
Author(s):  
Weiguo Liu ◽  
Dedong Pan ◽  
Shi Shen ◽  
Zeshao You ◽  
Yuechao Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Water Distribution ◽  
Hydrate Formation ◽  
Triaxial Tests ◽  
Water Mixture ◽  
Water Mixing ◽  
Low Field ◽  
Seeding Method ◽  
Hydrate Bearing Sediments

Laboratory-synthesized specimens are employed for an experimental study on the mechanical properties of hydrate-bearing sediments (HBS) due to the difficulty of field coring. A representative synthesized sample for the analysis of the mechanical properties of HBS in the experimental study requires evenly distributed hydrates in the pores of the sample. However, a specimen made with an improper sand–water mixing method might have an uneven water distribution, resulting in an uneven hydrate distribution when applying the ice-seeding method for hydrate formation. This study adopted three kinds of methods to mix sand and water before forming hydrates and applied the low-field nuclear magnetic resonance (NMR) technique to investigate how these methods affect the hydrate distribution, further affecting the mechanical properties. To analyze the mechanical properties of HBS, we conducted drained triaxial tests. As shown in low-field NMR, when we compacted a sample of the sand–water mixture and froze it upside-down before hydrate formation, a sample with an even water distribution was obtained. Subsequently, the hydrate in HBS distributed also evenly. The stress-strain curves present different strain softening and hardening patterns due to the different hydrate distributions. Moreover, the samples with the evenly distributed hydrates have higher initial elastic modulus and strength than the ones made with other methods.

Experimental study on methane hydrate formation in a partially saturated sandstone using low-field NMR technique

Fuel ◽  
2019 ◽  
Vol 251 ◽  
pp. 82-90 ◽  
Author(s):  
Yunkai Ji ◽  
Jian Hou ◽  
Guodong Cui ◽  
Nu Lu ◽  
Ermeng Zhao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Methane Hydrate ◽  
Hydrate Formation ◽  
Partially Saturated ◽  
Low Field ◽  
Low Field Nmr

A Study on the Differences of Mechanical Properties between CH4 and CO2 Hydrate-Bearing Sediments

2013 ◽  
Vol 353-356 ◽  
pp. 1240-1244 ◽  
Author(s):  
Yuan Luo ◽  
Yong Chen Song ◽  
Wei Guo Liu ◽  
Jia Fei Zhao ◽  
Yun Fei Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gas Hydrate ◽  
Triaxial Compression ◽  
Triaxial Tests ◽  
Long Term Storage ◽  
Replacement Method ◽  
Three Stages ◽  
The Stability ◽  
Hydrate Bearing Sediments

The CH4-CO2replacement method to recover CH4from hydrate-bearing sediments has received great attention because it enables the long term storage of CO2and is expected to maintain the stability of gas hydrate-bearing sediments. This paper extends our previous study of the stability of CH4hydrate-bearing sediments to CO2hydrate-bearing sediments to evaluate the safety of the CH4-CO2replacement method. Low temperature, high pressure triaxial compression apparatus was used to measure the mechanical properties of CO2hydrate-bearing sediments. The triaxial tests results for CH4and CO2hydrate-bearing sediments were then compared. It was found that the failure mode of both the CO2and CH4hydrate-bearing sediments was a bulging deformation at mid-height on the samples. Moreover, the stress-strain curves of both the CO2and CH4hydrate-bearing sediments appear to be hyperbolic in shape, and could be divided into three stages: the quasi-elastic stage, the hardening stage and the yield stage. However, the strength of the CO2hydrate-bearing sediments was approximately 15% larger than that of the CH4hydrate-bearing sediments under the same conditions. The results imply that the stability of gas hydrate-bearing sediments could be maintained using the CH4-CO2replacement method to recover CH4from these sediments.

The Assessment of Loosely and Tightly Bound Water in Water Distribution Changes of Human Cortical Bone by NMR

2008 ◽  
Author(s):  
Qingwen Ni ◽  
Huijie Leng ◽  
Daniel P. Nicolella
Keyword(s):  
Mechanical Properties ◽  
Cortical Bone ◽  
Water Distribution ◽  
Bound Water ◽  
Size Distributions ◽  
Low Field ◽  
Pore Size Distributions ◽  
Low Field Nmr ◽  
Non Destructive

Bone quality in terms of water distribution, porosity, and pore size distributions in cortical bone and relate these measures can be used to correlate bone mechanical properties. The objective of this paper is to demonstrate that non-destructive low-field NMR technique can be used to determine the mobile and the bound water distribution, and further determine the loosely and the tightly bound water in cortical bone in vitro.

Quantitatively study on methane hydrate formation/decomposition process in hydrate-bearing sediments using low-field MRI

Fuel ◽  
2020 ◽  
Vol 262 ◽  
pp. 116555 ◽  
Author(s):  
Yuying Zhang ◽  
Yuechao Zhao ◽  
Xu Lei ◽  
Mingjun Yang ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Methane Hydrate ◽  
Hydrate Formation ◽  
Decomposition Process ◽  
Low Field ◽  
Low Field Mri ◽  
Hydrate Bearing Sediments

Experimental study on mechanical properties of gas hydrate-bearing sediments using kaolin clay

2011 ◽  
Vol 25 (1) ◽  
pp. 113-122 ◽  
Author(s):  
Yang-hui Li ◽  
Yong-chen Song ◽  
Feng Yu ◽  
Wei-guo Liu ◽  
Jia-fei Zhao
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Gas Hydrate ◽  
Kaolin Clay ◽  
Hydrate Bearing Sediments

scholarly journals Characterization of Baboon Cortical Bone Microstructural Changes by Low Field NMR and Correlation of Bone Mechanical Properties

2020 ◽  
Vol 10 (11) ◽  
pp. 89-95
Author(s):  
Qingwen Ni ◽  
Anahi Tinajero ◽  
Daniel P. Nicolella
Keyword(s):  
Mechanical Properties ◽  
Relaxation Time ◽  
Cortical Bone ◽  
Water Distribution ◽  
Bound Water ◽  
T2 Relaxation ◽  
Relaxation Data ◽  
Bone Mechanical Properties ◽  
Mobile Water ◽  
Low Field

A NMR spin-spin (T2) relaxation technique has been described for determining the porosity, mobile and the bound water distribution in baboon cortical bone and correlate to their mechanical properties. The technique of low-field proton NMR involves spin-spin relaxation and free induction decay (FID) measurements, and the computational inversion methods for decay data analysis. The advantages of using NMR T2 relaxation techniques for bone water distribution are illustrated. The CPMG T2 relaxation data can be inverted to T2 relaxation distribution and this distribution then can be transformed to a pore size distribution with the longer relaxation times corresponding to larger pores. The FID T2 relaxation data can be inverted to T2 relaxation distribution and this distribution then can be transformed to bound and mobile water distribution with the longest relaxation time corresponding to mobile water and the middle relaxation time corresponding to bound water. The technique is applied to quantify apparent changes in porosity, bound and mobile water in cortical bone. Overall bone porosity is determined using the calibrated NMR fluid volume from the proton relaxation data divided by overall bone volume. The NMR porosity, bound and mobile water components are determined from cortical bone specimens obtained from baboon donors of different ages, and the results are correlated to bone mechanical properties.

Experimental study on mechanical properties of methane-hydrate-bearing sediments

2012 ◽  
Vol 28 (5) ◽  
pp. 1356-1366 ◽  
Author(s):  
Xu-Hui Zhang ◽  
Xiao-Bing Lu ◽  
Li-Min Zhang ◽  
Shu-Yun Wang ◽  
Qing-Ping Li
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Methane Hydrate ◽  
Hydrate Bearing Sediments

scholarly journals Crustal fingering facilitates free-gas methane migration through the hydrate stability zone

2020 ◽  
Vol 117 (50) ◽  
pp. 31660-31664
Author(s):  
Xiaojing Fu ◽  
Joaquin Jimenez-Martinez ◽  
Thanh Phong Nguyen ◽  
J. William Carey ◽  
Hari Viswanathan ◽  
...  
Keyword(s):  
Hydrate Formation ◽  
Elevated Pressure ◽  
Water Mixture ◽  
Gas Migration ◽  
Stability Zone ◽  
Critical Gap ◽  
Methane Seepage ◽  
Field Evidence ◽  
Hydrate Bearing Sediments ◽  
Hydrate Stability

Widespread seafloor methane venting has been reported in many regions of the world oceans in the past decade. Identifying and quantifying where and how much methane is being released into the ocean remains a major challenge and a critical gap in assessing the global carbon budget and predicting future climate [C. Ruppel, J. D. Kessler. Rev. Geophys. 55, 126–168 (2017)]. Methane hydrate (CH4⋅5.75H2O) is an ice-like solid that forms from methane–water mixture under elevated-pressure and low-temperature conditions typical of the deep marine settings (>600-m depth), often referred to as the hydrate stability zone (HSZ). Wide-ranging field evidence indicates that methane seepage often coexists with hydrate-bearing sediments within the HSZ, suggesting that hydrate formation may play an important role during the gas-migration process. At a depth that is too shallow for hydrate formation, existing theories suggest that gas migration occurs via capillary invasion and/or initiation and propagation of fractures (Fig. 1). Within the HSZ, however, a theoretical mechanism that addresses the way in which hydrate formation participates in the gas-percolation process is missing. Here, we study, experimentally and computationally, the mechanics of gas percolation under hydrate-forming conditions. We uncover a phenomenon—crustal fingering—and demonstrate how it may control methane-gas migration in ocean sediments within the HSZ.

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