An easy and efficient way to evaluate mechanical properties of gas hydrate-bearing sediments: The direct shear test

Abstract Understanding the mechanical behaviours of gas hydrate-bearing sediments (GHBS) is important for their associated applications in wellbore stability, stratum deformation during exploitation, geological disaster prevention, and the risk assessment of replacing CH 4 with CO 2 in hydrate reservoirs and CO 2 sequestration in oceans. However, triaxial tests on mechanical properties of GHBS are taxing and time-consuming. Here, we presented an easy and efficient way to evaluate these behaviours by using a self-developed direct shear apparatus. Then a series of direct shear tests on GHBS represented by CO 2 hydrate-bearing silt were performed to investigate their mechanical behaviours and strength indices by changing the axial pressure, CO 2 hydrate saturation, shear rate and hydrate synthesis temperature. Our results indicate that CO 2 hydrate significantly strengthens specimens by cementing silt grains. In addition, when hydrate saturation increases, the cohesions are enhanced from 0.09 to 2.39 MPa, and the internal friction angles increase and decrease at the range from 28.6° to 43.3° under the experimental conditions. These findings have direct implications for evaluating the stability and safety of natural gas hydrate reservoirs, CO 2 replacement to extract CH 4 and CO 2 sequestration.

[1]  Caglar Sinayuc,et al.  An experimental study on the CO2–CH4 swap process between gaseous CO2 and CH4 hydrate in porous media , 2014 .

[2]  J. Nagao,et al.  Mechanical properties of hydrate-bearing turbidite reservoir in the first gas production test site of the Eastern Nankai Trough , 2015 .

[3]  J. Santamarina,et al.  Hydro-bio-geomechanical properties of hydrate-bearing sediments from Nankai Trough , 2015 .

[4]  Thijs J. H. Vlugt,et al.  Mechanical properties of clathrate hydrates: status and perspectives , 2012 .

[5]  Feng Yu,et al.  A new strength criterion and constitutive model of gas hydrate-bearing sediments under high confining pressures , 2013 .

[6]  G. Ali Mansoori,et al.  An introduction to natural gas hydrate/clathrate: The major organic carbon reserve of the Earth , 2007 .

[7]  Tae Sup Yun,et al.  Physical properties of hydrate‐bearing sediments , 2009 .

[8]  William F. Waite,et al.  Methane gas hydrate effect on sediment acoustic and strength properties , 2007 .

[9]  Ayhan Demirbas,et al.  Methane hydrates as potential energy resource: Part 2 – Methane production processes from gas hydrates , 2010 .

[10]  Arun Kumar Jain,et al.  Soil Mechanics And Foundations , 2005 .

[11]  K. Ohgaki,et al.  Exploitation of CH_4 Hydrates under the Nankai Trough in Combination with CO_2 Storage , 1994 .

[12]  J. F. Wright,et al.  Relation between Gas Hydrate and Physical Properties at the Mallik 2L‐38 Research Well in the Mackenzie Delta , 2000 .

[13]  Qingping Li,et al.  Experimental study on mechanical properties of methane-hydrate-bearing sediments , 2012 .

[14]  Malcolm Mellor,et al.  Deformation and Fracture of Ice Under Uniaxial Stress , 1972, Journal of Glaciology.

[15]  J. Nagao,et al.  Triaxial testing system for pressure core analysis using image processing technique. , 2013, The Review of scientific instruments.

[16]  J. Y. Lee,et al.  Physical properties of sediments from the Ulleung Basin, East Sea: Results from Second Ulleung Basin Gas Hydrate Drilling Expedition, East Sea (Korea) , 2013 .

[17]  Weiguo Liu,et al.  Effect of confining pressure on mechanical behavior of methane hydrate-bearing sediments , 2011 .

[18]  Carolyn A. Koh,et al.  Clathrate hydrates of natural gases , 1990 .

[19]  S Kjelstrup,et al.  Compressibility, thermal expansion coefficient and heat capacity of CH4 and CO2 hydrate mixtures using molecular dynamics simulations. , 2015, Physical chemistry chemical physics : PCCP.

[20]  Masaki Ota,et al.  Methane recovery from methane hydrate using pressurized CO2 , 2005 .

[21]  W. Waite,et al.  Methane hydrate formation in partially water-saturated Ottawa sand , 2004 .

[22]  Anyi Hu,et al.  CO2 sequestration by methanogens in activated sludge for methane production , 2015 .

[23]  Kazuo Aoki,et al.  Mechanical Properties of Sandy Sediment Containing Marine Gas Hydrates In Deep Sea Offshore Japan , 2007 .

[24]  S. Kjelstrup,et al.  Mechanical instability of monocrystalline and polycrystalline methane hydrates , 2015, Nature Communications.

[25]  K. Kvenvolden,et al.  A primer on gas hydrates , 1993 .

[26]  Yukio Nakata,et al.  Mechanical and dissociation properties of methane hydrate-bearing sand in deep seabed , 2013 .

[27]  Yukio Nakata,et al.  A comparative analysis of the mechanical behavior of carbon dioxide and methane hydrate-bearing sediments , 2014 .

[28]  C.R.I. Clayton,et al.  Potential impact of gas hydrate and its dissociation on the strength of host sediment in the Krishna–Godavari Basin , 2014 .

[29]  Jiafei Zhao,et al.  Experimental measurements of mechanical properties of carbon dioxide hydrate-bearing sediments , 2013 .

[30]  Kiyoteru Takano,et al.  Methane Exploitation by Carbon Dioxide from Gas Hydrates—Phase Equilibria for CO2-CH4 Mixed Hydrate System— , 1996 .

[31]  J. Grozic,et al.  Strength behavior of methane hydrate bearing sand in undrained triaxial testing , 2013 .

[32]  Jiafei Zhao,et al.  Mechanical property of artificial methane hydrate under triaxial compression , 2010 .

[33]  Yukio Nakata,et al.  Basic research on the mechanical behavior of methane hydrate-sediments mixture , 2005 .

[34]  Tsutomu Yamaguchi,et al.  Effect of Confining Pressure on Mechanical Properties of Sediment Containing Synthetic Methane Hydrate , 2010 .

[35]  Tae Sup Yun,et al.  Observations of pore‐scale growth patterns of carbon dioxide hydrate using X‐ray computed microtomography , 2015 .

[36]  Yukio Nakata,et al.  Mechanical behavior of gas‐saturated methane hydrate‐bearing sediments , 2013 .

[37]  Yukio Nakata,et al.  Development of high-pressure low-temperature plane strain testing apparatus for methane hydrate-bearing sand , 2013 .

[38]  Yukio Nakata,et al.  Effects of dissociation on the shear strength and deformation behavior of methane hydrate-bearing sediments , 2014 .

[39]  Tae Sup Yun,et al.  Mechanical properties of sand, silt, and clay containing tetrahydrofuran hydrate , 2007 .

[40]  A. Mohammadi,et al.  Thermodynamic modeling of pressure–temperature phase diagrams of binary clathrate hydrates of methane, carbon dioxide or nitrogen + tetrahydrofuran, 1,4-dioxane or acetone , 2012 .

[41]  Feng Yu,et al.  Analyses of stress strain behavior and constitutive model of artificial methane hydrate , 2011 .

[42]  J. Sangwai,et al.  Effect of silica sand size on the formation kinetics of CO2 hydrate in porous media in the presence of pure water and seawater relevant for CO2 sequestration , 2014 .

[43]  K. Kvenvolden.  Methane hydrate — A major reservoir of carbon in the shallow geosphere? , 1988 .

[44]  J. Nagao,et al.  Mechanical behavior of hydrate-bearing pressure-core sediments visualized under triaxial compression , 2015 .

[45]  T.H.W. Baker.  Strain rate effect on the compressive strength of frozen sand , 1979 .