scholarly journals A review of the gas hydrate distribution offshore Chilean margin

2021 ◽  
Vol 230 ◽  
pp. 01007
Author(s):  
Ivan Vargas-Cordero de la Cruz ◽  
Michela Giustiniani ◽  
Umberta Tinivella ◽  
Giulia Alessandrini

In last decades, the Chilean margin has been extensively investigated to better characterize the complex geological setting through the acquisition of geophysical data and, in particular, seismic lines. The analysis of seismic lines allowed identifying the occurrence of gas hydrates and free gas in many places along the margin. Clearly, the gas hydrate reservoir could be a strategic energy reserve for Chile, but, on the other hand, the dissociated of gas hydrate due to climate change could be an issue to face. Moreover, this region is characterized by large and mega-scale earthquakes that may contribute to gas hydrate dissociation and consequent submarine slides triggering. In this context, Chilean margin should be considered a natural laboratory to study the hydrate system evolution.

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 709
Author(s):  
Ivan Vargas-Cordero ◽  
Michela Giustiniani ◽  
Umberta Tinivella ◽  
Lucia Villar-Muñoz ◽  
Giulia Alessandrini

In recent decades, the Chilean margin has been extensively investigated to better characterize the complex geological setting through the geophysical data. The analysis of seismic lines allowed us to identify the occurrence of gas hydrates and free gas in many places along the margin and the change of the pore fluid due to the potential hydrate dissociation. The porosity reduction due to the hydrate presence is linked to the slope to identify the area more sensitive in case of natural phenomena or induced by human activities that could determine gas hydrate dissociations and/or leakage of the free gas trapped below the gas-hydrate stability zone. Clearly, the gas hydrate reservoir could be a strategic energy reserve for Chile. The steady-state modelling pointed out that the climate change could determine gas hydrate dissociation, triggering slope failure. This hypothesis is supported by the presence of high concentrations of gas hydrate in correspondence of important seafloor slope. The dissociation of gas hydrate could change the petrophysical characteristics of the subsoil triggering slopes, which already occurred in the past. Consequently, it is required to improve knowledge about the behavior of the gas hydrate system in a function of complex natural phenomena before the exploitation of this important resource.


2020 ◽  
Author(s):  
Michela Giustiniani ◽  
Umberta Tinivella

Few potential distributing areas of gas hydrates have been recognized in literature in Antarctica: the South Shetland continental margin, the Weddell Sea, the Ross Sea continental margin and the Wilkes Land continental margin. The most studied part of Antarctica from gas hydrate point of view is the South Shetland margin, where an important gas hydrate reservoir was well studied with the main purpose to determine the relationship between hydrate stability and environment effects, including climate change. In fact, the climate signals are particularly amplified in transition zones such as the peri-Antarctic regions, suggesting that the monitoring of hydrate system is desirable in order to detect potential hydrate dissociation as predicted by recent modeling offshore Antarctic Peninsula. The main seismic indicator of the gas hydrate presence, the bottom simulating reflector, was recorded in few parts of Antarctica, but in some cases it was associated to opal A/CT transition. The other areas need further studies and measurements in order to confirm or refuse the gas hydrate presence.


2016 ◽  
Vol 50 (6) ◽  
pp. 58-68 ◽  
Author(s):  
Narayanaswamy Vedachalam ◽  
Sethuraman Ramesh ◽  
Arunachalam Umapathy ◽  
Gidugu Ananda Ramadass

AbstractNatural gas hydrates are considered to be a strategic unconventional hydrocarbon resource in the Indian energy sector, and thermal stimulation is considered as one of the methods for producing methane from gas hydrate-bearing sediments. This paper discusses the importance of this abundantly available blue economic resource and analyzes the efficiency of methane gas production by circulating hot water in a horizontal well in the fine-grained, clay-rich natural gas hydrate reservoir in the Krishna-Godavari basin of India. Analysis is done using the electrothermal finite element analysis software MagNet-ThermNet and gas hydrate reservoir modeling software TOUGH+HYDRATE with reservoir petrophysical properties as inputs. Energy balance studies indicate that, in the 90% hydrate-saturated reservoir, the theoretical energy conversion ratio is 1:4.9, and for saturations below 20%, the ratio is <1. It is identified that a water flow of 0.2 m3/h at 270°C is required for every 1 m2 of wellhead surface area to dissociate gas hydrates up to a distance of 2.6 m from the well bore within 36 h.


Author(s):  
Tao Yu ◽  
Weiguo Liu ◽  
Jiafei Zhao ◽  
Yongchen Song ◽  
Yu Liu

The paper presented a numerical model on the gas hydrate production by depressurization. During the simulation a one-dimensional dissociation model applied to a gas hydrate reservoir was set up to simulate the process of gas hydrate production by depressurization. Based on the calculation results, influences of the gas pressure, saturation, porosity and absolute permeability on the production effect were studied respectively. The results obtained from the sensitivity analysis provide theoretical supported for the actual gas hydrate production.


Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 234 ◽  
Author(s):  
Giulia Alessandrini ◽  
Umberta Tinivella ◽  
Michela Giustiniani ◽  
Iván de la Cruz Vargas-Cordero ◽  
Silvia Castellaro

In the last few years, interest in the offshore Chilean margin has increased rapidly due to the presence of gas hydrates. We have modelled the gas hydrate stability zone off Chilean shores (from 33° S to 46° S) using a steady state approach to evaluate the effects of climate change on gas hydrate stability. Present day conditions were modelled using published literature and compared with available measurements. Then, we simulated the effects of climate change on gas hydrate stability in 50 and 100 years on the basis of Intergovernmental Panel on Climate Change and National Aeronautics and Space Administration forecasts. An increase in temperature might cause the dissociation of gas hydrate that could strongly affect gas hydrate stability. Moreover, we found that the high seismicity of this area could have a strong effect on gas hydrate stability. Clearly, the Chilean margin should be considered as a natural laboratory for understanding the relationship between gas hydrate systems and complex natural phenomena, such as climate change, slope stability and earthquakes.


2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Wei-Li Hong ◽  
Marta E. Torres ◽  
JoLynn Carroll ◽  
Antoine Crémière ◽  
Giuliana Panieri ◽  
...  

Abstract Arctic gas hydrate reservoirs located in shallow water and proximal to the sediment-water interface are thought to be sensitive to bottom water warming that may trigger gas hydrate dissociation and the release of methane. Here, we evaluate bottom water temperature as a potential driver for hydrate dissociation and methane release from a recently discovered, gas-hydrate-bearing system south of Spitsbergen (Storfjordrenna, ∼380 m water depth). Modelling of the non-steady-state porewater profiles and observations of distinct layers of methane-derived authigenic carbonate nodules in the sediments indicate centurial to millennial methane emissions in the region. Results of temperature modelling suggest limited impact of short-term warming on gas hydrates deeper than a few metres in the sediments. We conclude that the ongoing and past methane emission episodes at the investigated sites are likely due to the episodic ventilation of deep reservoirs rather than warming-induced gas hydrate dissociation in this shallow water seep site.


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