Deep sea NMR: Methane hydrate growth habit in porous media and its relationship to hydraulic permeability, deposit accumulation, and submarine slope stability

Author(s):  
R. L. Kleinberg ◽  
C. Flaum ◽  
D. D. Griffin ◽  
P. G. Brewer ◽  
G. E. Malby ◽  
...  
Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5090
Author(s):  
Qingsheng Liu ◽  
Jinjia Guo ◽  
Wangquan Ye ◽  
Kai Cheng ◽  
Fujun Qi ◽  
...  

As a powerful in situ detection technique, Raman spectroscopy is becoming a popular underwater investigation method, especially in deep-sea research. In this paper, an easy-to-operate underwater Raman system with a compact design and competitive sensitivity is introduced. All the components, including the optical module and the electronic module, were packaged in an L362 × Φ172 mm titanium capsule with a weight of 20 kg in the air (about 12 kg in water). By optimising the laser coupling mode and focusing lens parameters, a competitive sensitivity was achieved with the detection limit of SO42− being 0.7 mmol/L. The first sea trial was carried out with the aid of a 3000 m grade remotely operated vehicle (ROV) “FCV3000” in October 2018. Over 20,000 spectra were captured from the targets interested, including methane hydrate, clamshell in the area of cold seep, and bacterial mats around a hydrothermal vent, with a maximum depth of 1038 m. A Raman peak at 2592 cm−1 was found in the methane hydrate spectra, which revealed the presence of hydrogen sulfide in the seeping gas. In addition, we also found sulfur in the bacterial mats, confirming the involvement of micro-organisms in the sulfur cycle in the hydrothermal field. It is expected that the system can be developed as a universal deep-sea survey and detection equipment in the near future.


Géotechnique ◽  
2016 ◽  
Vol 66 (3) ◽  
pp. 188-201 ◽  
Author(s):  
A. M. Puzrin ◽  
L. N. Germanovich ◽  
B. Friedli

Author(s):  
Eric C. Otto

     Read as apocalyptic ecothrillers, Frank Schätzing’s The Swarm and Liz Jensen’s The Rapture do not offer much in the way of critical reflection on the ecocatastrophes they stage. The Swarm’s focus on the feat of confronting the violent efforts of a superintelligent, deep-sea species to protect its ocean habitat against continued human exploitation and The Rapture’s focus on the feat of locating on time the psychically-predicted disaster zone of an impending undersea calamity overshadow their more than occasional spotlighting of, for example, the dangers of methane hydrate mining. Science fiction, however, requires readers to be attentive to those narrative moments when incongruities between the known world and the extrapolated world of the text emerge with critical, not just plot-supporting, purpose. Fundamental to the reading and interpretation of science fiction is the reader’s awareness of the genre’s extrapolative practice, which connects the now with the imagined then and therefore instigates critical thinking about present human practices. Read as extrapolative science fiction, The Swarm and The Rapture gain merit as ecopolitical works, for “science fiction reading” mobilizes the latent ecopolitics of ecothrillers, ecopolitics that “ecothriller reading” would otherwise diminish or fail to notice.   Resumen               Considerados ecothrillers apocalípticos, The Swarm de Frank Schätzing y The Rapture de Liz Jensen no ofrecen mucha reflexión crítica sobre las eco-catástrofes que presentan. The Swarm se centra en los violentos esfuerzos de una especie superinteligente que habita las profundidades para proteger su hábitat marino frente a la continua explotación humana. Por su parte,  al centrarse The Rapture en la hazaña de ubicar en el tiempo la zona catastrófica de un desastre submarino inminente que ha sido predicho psicológicamente, se eclipsan las más que ocasionales referencias a, por ejemplo, los peligros de la minería de hidrato de metano. La ciencia ficción, sin embargo, requiere que los lectores estén atentos a esos momentos narrativos en los que las incongruencias entre el mundo conocido y el mundo extrapolado del texto surjan con objetivo crítico, y no sólo para respaldar el argumento. Es fundamental para la lectura y la interpretación de la ciencia ficción la conciencia por parte del lector de la práctica extrapolativa del género, que conecta el ahora con el entonces imaginado, incitando así a reflexionar críticamente sobre el comportamiento humano en la actualidad. Considerados ciencia ficción extrapolativa, The Swarm y The Rapture ganan mérito como obras eco-políticas, porque "la lectura de ciencia ficción" moviliza la eco-política latente de  los eco-thrillers – eco-política que en "la lectura de eco-thrillers" de otra forma pasaría desapercibida.


2017 ◽  
Vol 31 (8) ◽  
pp. 8548-8559 ◽  
Author(s):  
Liang Zhang ◽  
Sudan Xu ◽  
Xin Li ◽  
Yin Zhang ◽  
Ruohan Yang ◽  
...  

2007 ◽  
Vol 44 (3) ◽  
pp. 314-325 ◽  
Author(s):  
M F Nixon ◽  
J LH Grozic

Gas hydrates are icelike compounds composed of water and methane gas in very compact form. There is substantial evidence from case histories that links gas hydrate dissociation to submarine slope failures and other geohazards. Theoretical analyses have also shown that upon dissociation gas hydrates will cause an increase in fluid pressure and a reduction in effective stress and thus result in loss of the soil strength. This paper presents a preliminary quantification of the effects of gas hydrate dissociation through development of a pore-pressure model that was incorporated into one- and two-dimensional slope stability analyses. The ensuing numerical study investigated submarine slope stability through parametric studies and application to two important case histories and found that dissociation of even small amounts of hydrate can have a significant destabilizing effect. Yet whether gas hydrate dissociation can alone cause large-scale slope failures has still to be demonstrated as there are often many destabilizing processes; however, this research highlights the importance of assessing the effects of gas hydrate dissociation on the behaviour of submarine slopes.Key words: gas hydrates, slope stability, marine, offshore, methane gas, instability.


2015 ◽  
Vol 55 (29) ◽  
pp. 7981-7991 ◽  
Author(s):  
Zheng Rong Chong ◽  
Mingjun Yang ◽  
Boo Cheong Khoo ◽  
Praveen Linga

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