Exploration of permafrost with audiomagnetotelluric data for gas hydrates in the Juhugeng Mine of the Qilian Mountains, China

Geophysics ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. B247-B258 ◽  
Author(s):  
Bo Yang ◽  
Xiangyun Hu ◽  
Wule Lin ◽  
Shuang Liu ◽  
Hui Fang
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Qilian Mountains ◽  
High Resistivity ◽  
Electromagnetic Methods ◽  
Survey Technique ◽  
Resistivity Logs ◽  
Gas Hydrate Deposits ◽  
The Qilian Mountains ◽  
The Impact

In China, gas hydrates in onshore permafrost areas have so far only been found in the Juhugeng Mine of the Qilian Mountains. However, their subsurface distribution remains unclear. Electrical resistivity logs have revealed that zones containing gas hydrates have higher resistivity than surrounding zones, which makes electromagnetic methods viable for detecting gas-hydrate deposits. We have deployed a natural-source audio-magnetotelluric (AMT) survey at the Juhugeng Mine. AMT data were collected at 176 sites along five profiles, and resistivity models were derived from 2D inversions after detailed data analysis. After the available geologic and geophysical observations were combined, the inversion results from profile 1 suggested that permafrost near the surface with high resistivity and thickness is essential for underlying gas hydrates to be present. The decrease in resistivity and/or thickness of permafrost due to climate change may lead to gas-hydrate dissociation. The other four AMT transects suggested three prospective gas-hydrate sites. Our results indicate that the AMT survey technique is suitable for exploring gas hydrates in permafrost areas and analyzing the impact of permafrost characteristics on gas-hydrate occurrence.

scholarly journals Mapping and Evaluating Human Pressure Changes in the Qilian Mountains

2021 ◽  
Vol 13 (12) ◽  
pp. 2400
Author(s):  
Quntao Duan ◽  
Lihui Luo ◽  
Wenzhi Zhao ◽  
Yanli Zhuang ◽  
Fang Liu
Keyword(s):  
Human Activities ◽  
Qilian Mountains ◽  
Western China ◽  
Eastern Region ◽  
Human Pressure ◽  
Activity Intensity ◽  
Human Footprint ◽  
Illegal Activities ◽  
The Qilian Mountains ◽  
The Impact

Human activities have dramatically changed ecosystems. As an irreplaceable ecological barrier in western China, the Qilian Mountains (QLM) provide various ecosystem services for humans. To evaluate the changes in the intensity of human activities in the QLM and their impact on the ecosystem, the human footprint (HF) method was used to conduct a spatial dataset of human activity intensity. In our study, the NDVI was used to characterize the growth of vegetation, and six categories of human pressures were employed to create the HF map in the QLM for 2000–2015 at a 1-km scale. The results showed that the mean NDVI during the growing season showed a significant increasing trend over the entire QLM in the period 2000–2015, while the NDVI showed a significant declining trend of more than 70% concentrated in Qinghai. Human pressure throughout the QLM occurred at a low level during 2000–2015, being greater in the eastern region than the western region, while the Qinghai area had greater human pressure than the Gansu area. Due to the improvement in traffic facilities, tourism, overgrazing, and other illegal activities, grasslands, shrublands, forests, wetlands, and bare land were the vegetation types most affected by human activities (in decreasing order). As the core area of the QLM, the Qilian Mountains National Nature Reserve (NR) has effectively reduced the impact of human activities. However, due to the existence of many ecological historical debts caused by unreasonable management in the past, the national park established in 2017 is facing great challenges to achieve its goals. These data and results will provide reference and guidance for future protection and restoration of the QLM ecosystem.

Characterising Gas Hydrate Deposits on New Zealand's Southern Hikurangi Margin using Seismic Reflection Data

2021 ◽  
Author(s):  
◽  
Hanyan Wang
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Research Area ◽  
Low Velocity ◽  
Seismic Reflection Data ◽  
Free Gas ◽  
Reflection Data ◽  
Geological Conditions ◽  
Gas Hydrate Deposits ◽  
Seismic Lines

<p>Reprocessed Bruin 2D seismic data (recorded in 2006) from New Zealand Hikurangi Margin are presented and analyzed to show the presence of gas hydrates. We choose six seismic lines that each showed bottom-simulating reflections (BSRs) that are important indicators for the presence of gas hydrate. The aim is to obtain a higher resolution image of the shallow subsurface structures and determine the nature of the gas hydrate system in this area.  To further investigate the presence of Gas Hydrates was undertaken. There is a strong correlation between anomalous velocities and the depths of BSRs, which supports the presence of gas hydrates in the research area and is useful for detecting areas of both free gas and gas hydrate along the seismic lines.  The combination of high-resolution seismic imaging and velocity analysis is the key method for showing the distribution of gas hydrates and gas pockets in our research area. The results indicate that the distribution of both free gas and gas hydrate is strongly localized. The Discussion Chapter gives several concentrated gas hydrate deposits in the research area. Idealized scenarios for the formation of the gas hydrates are proposed. In terms of identifying concentrated gas hydrate deposits we propose the identification of the following key seismic attributes: 1) existence of BSRs, 2) strong reflections above BSRs in the gas hydrate stability zone, 3) enhanced reflections related to free gas below BSRs, 4) appropriate velocity anomalies (i.e. low velocity zones beneath BSRs and localized high-velocity zones above BSRs).  This study contributes to the understanding of the geological conditions and processes that drives the deposition of concentrated gas hydrate deposits on this part of the Hikurangi Margin.</p>

scholarly journals The Impact of Mountain Range Geographic Orientation on the Altitude Effect of Precipitation δ18O in the Upper Reaches of the Heihe River Basin in the Qilian Mountains

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1797 ◽  
Author(s):  
Jianqiao He ◽  
Wei Zhang ◽  
Yuwei Wu
Keyword(s):  
Water Vapor ◽  
River Basin ◽  
Qilian Mountains ◽  
Heihe River Basin ◽  
Heihe River ◽  
Mountain Range ◽  
The Qilian Mountains ◽  
The Impact ◽  
The Heihe River Basin ◽  
Precipitation Δ18o

The precipitation δ18O-elevation gradients are important for paleoclimate, hydrology, and paleoelevation studies. The field setting for this research was the upper reaches of the Heihe River Basin within the Qilian Mountains in the Northern Tibetan Plateau. Three study sites were established along the Heihe main river. These sites were the Yingluoxia and Qilian hydrological stations and the Yeniugou meteorological station. The Yingluoxia hydrological station was the dividing point between the upper and middle reaches of the Heihe River Basin. The altitudes of these sites range from 1600 m to 3300 m. Summer precipitation is predominant with regard to the annual precipitation amount. By analysis of variance (ANOVA), the precipitation δ18O data collected from the three sites were analyzed, spanning a year of precipitation data from 2007.10 to 2008.9. The results showed that the δ18O-elevation gradient was not significant (α = 0.05) at a seasonal or annual scale in this region and the precipitation-weighted annual mean δ18O was −7.1‰. Mechanisms that have been proposed to explain this result consider the role of two processes, including (1) mixing of moisture sources, a process common in an arid and semiarid region, and (2) the absence of a mechanism for water vapor to climb along slopes in the precipitation system. Atmospheric water vapor mainly travels along the trend of the Qilian Mountains range rather than climbing it because this region is dominated by the westerlies and the trend of the Qilian mountains is geographically aligned to the NWW (north-west-west) direction. We demonstrated that, aside from the water vapor source, the spatial relationship between the water vapor transport pathway and the trend of the mountain range are the main driving factors associated with the stable isotope trends in precipitation. As a result, it is important to re-recognize the timing and location of groundwater recharge in the Heihe River Basin.

scholarly journals Effect of permafrost properties on gas hydrate petroleum system in the Qilian Mountains, Qinghai, Northwest China

2014 ◽  
Vol 16 (12) ◽  
pp. 2711-2720 ◽  
Author(s):  
Pingkang Wang ◽  
Xuhui Zhang ◽  
Youhai Zhu ◽  
Bing Li ◽  
Xia Huang ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Gas Hydrate ◽  
Northwest China ◽  
Qilian Mountains ◽  
Petroleum System ◽  
Stability Zone ◽  
The Qilian Mountains ◽  
Hydrate Stability

Evolution of gas hydrate petroleum system in the Qilian Mountains permafrost: (A) end of Late Pleistocene and (B) modern day. GHSZ indicates gas hydrate stability zone.

scholarly journals Application of resonant oscillatory systems for the seafloor gas hydrates development

2021 ◽  
Vol 230 ◽  
pp. 01020
Author(s):  
Hennadii Haiko ◽  
Oleksandr Zhivkov ◽  
Lubov Pyha
Keyword(s):  
Energy Consumption ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Methane Hydrates ◽  
High Quality ◽  
Technical Problems ◽  
Gas Recovery ◽  
Oscillatory Systems ◽  
Industrial Experiments ◽  
Gas Hydrate Deposits

The prospects for the gas recovery from bottom gas hydrates are studied, and the necessity for the formation of an innovation environment and practical steps for conducting industrial experiments are formulated. The promising methods of shielded development of seafloor gas hydrate deposits are analyzed and the technical problems of their improvement are revealed. The possibilities of using resonant oscillatory systems for the shielded development of bottom gas hydrates are studied, in particular, a Helmholtz flow-excited resonator. The expediency of using high-quality oscillations of the “rotator” type has been substantiated in order to facilitate controlled gas hydrates dissociation over large areas of a gas hydrate field and to counteract the formation of new gas hydrates in the fractures of hydraulic reservoir fracturing. A method has been developed of gas recovery from bottom methane hydrates using a resonator device, which significantly reduces the energy consumption for the gas hydrates dissociation and contributes to the technological processes control.

scholarly journals GAS HYDRATES – HISTORY OF DISCOVERY

2019 ◽  
pp. 45-49
Author(s):  
S. V. Goshovskyi ◽  
Oleksii Zurian
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Oil And Gas ◽  
Earth’S Crust ◽  
The Usa ◽  
History Of ◽  
Gas Hydrate Deposits ◽  
Earth's Crust ◽  
Research Institute

The literature sources dealing with the history of gas hydrate studies and discovery of possible existence of gas hydrate deposits in natural conditions were analyzed. They contain facts proving that within 1966 and 1969 the conditions for formation of hydrates in porous medium were researched at the Department of Gas and Gas Condensate Deposits Development and Exploitation of Gubkin Russian State University of Oil and Gas. The first experiments were set up by the Ukraine-born Yurij F. Makogon, Department Assistant Professor. The results proved possibility of formation and stable existence of gas hydrates in earth’s crust and became a scientific substantiation of natural gas hydrate deposits discovery. In 1969 the exploitation of Messoyakha deposits in Siberia started and it was the first time when the natural gas was derived directly from hydrates. The same year that invention was officially recognized and registered. Following the comprehensive international expert examination the State Committee on Inventions and Findings of the USSR Council of Ministers assumed that the citizens of the USSR Yurij F. Makogon, Andrej A. Trofimuk, Nikolaj V. Cherskij and Viktor G. Vasilev made a discovery described as follows: “Experiments proved previously unknown ability of natural gas to form deposits in the earth’s crust in solid gas hydrate state under definite thermodynamic conditions (Request dated March 19, 1969)”. The authors were presented with diplomas on March 4, 1971. From then onwards the issue of natural gas hydrates existence was widely researched all around the world. In 1985 Yurij F. Makogon became a Professor. Since 1973 he was a head of the gas hydrate laboratory in the All-Russian Scientific Research Institute of Natural Gases and Gas Technologies. Within 1974–1987 he was a head of the gas hydrate laboratory in Oil and Gas Research Institute RAS. In 1992 he was invited by one of the largest universities of the USA to arrange modern laboratory for gas hydrate study. The laboratory was created in the Texas University, USA and in 1995 Yurij Makogon became its head. As far as interest in gas hydrates increases Yurij F. Makogon reports at 27 international congresses and conferences, gives lectures in 45 world leading universities, functions as an academic adviser and participates in different international programs on research and exploitation of gas hydrate deposits in USA, Japan and India. The heritage of the scientist includes 27 patents, eight monographs (four of them were translated and published in the USA and Canada) and more than 270 scientific articles.

scholarly journals Geological and structural prerequisites of gas-bearing capacity and gas hydrate formation in the World Ocean (in terms of the Black Sea)

2018 ◽  
Vol 27 (2) ◽  
pp. 294-304
Author(s):  
E. Maksymova ◽  
S. Kostrytska
Keyword(s):  
Black Sea ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
World Ocean ◽  
Ocean Floor ◽  
The Black Sea ◽  
Sea Floor ◽  
The World ◽  
Gas Hydrate Deposits ◽  
Gas Bearing

Gas hydrates occurring in the World Ocean are considered as the additional and perspective non-traditional resource of hydrocarbon materials. The proposed classification of deposits as for mining and geological conditions of their occurrence as well as methodological approach to their development and calculation of technological parameters of methane extraction from the World Ocean floor with minimum impact upon the Earth’s hydrosphere is of considerable importance in the context of current studies of new and most prospective source of energy in terms of the available experience gap as for the development of gas hydrate deposits. The approach to search for and explore gas hydrate deposits occurring on and under the World Ocean floor has been suggested; the approach is based upon the regularities of gas hydrate distribution in lithological varieties and geological structures. The necessity to take into consideration the pore space enclosing gas hydrate thicknesses to calculate their reserves has been substantiated. The overview of scientific literature sources summarizingthe results of marine expeditions as well as the analysis of publications of world scientific community dealing with the studies of gas hydrates has made it possible to determine that gas hydrate deposits are associated to the zones of jointing of continental plates and oceanic troughs. In their turn, those zones, due to different genesis, are made up of the corresponding various products of sedimentary rock accumulations. Detailed analysis of the Black Sea floor structure has been performed. Three geomorphological zones have been singled out; basic types of gas-bearing capacity manifestation and methane liberation from the interior have been represented. Quantitative evaluation of methane content in gas hydrate deposits has been given taking into account the detected ones. Data concerning gas-bearing capacity of the Black Sea floor proved by the map of mud volcanoes location within the areas of gas hydrate sampling have been considered. That was the basis to analyze peculiarities of the formation of bottom-sediment gas hydrates basing upon genetic origin of lithological composition of their enclosing rocks and their structures in terms of the Black Sea floor. Relation between the features of the World Ocean floor structure and the distribution of gas hydrate deposits has been determined. Theoretical approach to search for and explore gas hydrate deposits both in the Black Sea and in the World Ocean has been developed and proposed. Interaction between different zones of the World Ocean floor and types of gas hydrate deposits based upon the compositions of their enclosing rock has been shown. Lithological composition of the rocks enclosing gas hydrates has been analyzedin detail. That will make it possible to determine the type of any specific deposit and elaborate technological scheme to open and develop methane-containing gas hydrate deposits.

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