The Characteristics of Gas Hydrates Recovered from Shenhu Area in the South China Sea

Liu, Changling; Ye, Yuguang; Meng, Qingguo; He, Xianqiang; Lu, Hailong; Zhang, Jian; Liu, Jian; Yang, Shengxiong

doi:10.1016/j.margeo.2012.03.004

Cited by 171 publications

(76 citation statements)

References 30 publications

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“…Shenhu area is in the middle of the northern slope of SCS, between Xisha Trough and Dongsha Islands, and tectonically located in the Zhu II Depression, Pearl River Mouth Basin, that has been in the process of tectonic subsidence since the middle Miocene ). Water depth ranges between 800 m and 2,000 m, with complex submarine topography (Liu et al 2012). A central diapiric zone with various types of diapiric structures, such as turtleback-like arches, weak piercing, gas chimneys, diapir faults (or cracks), mud volcanoes and seabed pockmarks (Wang et al 2006a;Wu et al 2013) was observed in this area.…”

Section: Geological Settingmentioning

confidence: 89%

Geochemical and magnetic signals for the mud volcano-induced methane seepage in the core sediments of Shenhu area, northern South China Sea

et al. 2014

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The Shenhu Area of the northern South China Sea (SCS) has been regarded as a promising area for gas hydrate exploration. In this research, the petrography and stable isotopic composition of authigenic carbonates within a core of shallow sediment from Site 08CF7 in the Shenhu area have been studied. Based on the results of grain sizes, magnetic susceptibility, carbonate contents, textural characteristics, the age constrains of the core and the tectonic setting of the study area, it can be inferred that the core may represent the subsurface sediment in a mud volcano area within the gas hydrate system. Core sediments below 188 cm in the core may be associated with the in situ mud volcano activity. The authigenic carbonates (calcite, aragonite and dolomite) in fine size fraction below 188 cm indicate the mud volcano-induced methane seepage and anaerobic oxidation of methane (AOM), and their carbon source was mainly biogenic methane. In addition, the variation in magnetic susceptibility corresponds with in situ mud volcano sediments and associated methane seepage. These signals provide new methods of identifying AOM and application prospect for the exploration of seepage gas hydrates in SCS.

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Section: Geological Settingmentioning

confidence: 89%

Geochemical and magnetic signals for the mud volcano-induced methane seepage in the core sediments of Shenhu area, northern South China Sea

et al. 2014

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“…Chen et al [40] found that gas hydrate containing sediment layers in the Shenhu area were rich in calcareous nanofossils and foraminifers. Calcareous nanofossils and foraminifers are small, but they are larger than most sediment grains in the Shenhu area; thus they probably aided gas hydrate formation and accumulation by increasing the sediment porosity [3]. Sediments rich in such bioclasts have not been found in the PRM basin.…”

Section: Thermal Transport Propertiesmentioning

confidence: 99%

“…The migration of grains could lead to serious problems in production. The mean grain size of sediments from the PRM basin is relatively finer than sediments in the Shenhu area where GMGS1 was conducted [3]. Thus when selecting the optimum screen system for gas production, grain migration concepts adapted from soil-mechanics could be useful.…”

Section: Grain Migration Behaviormentioning

confidence: 99%

“…As a potential alternative strategic energy source and for the possible impact on the global climate, natural gas hydrates have aroused worldwide attention [1][2][3][4][5]. Gas hydrates are non-stoichiometric inclusion compounds made from water and light molecules, which are stable under high-pressure and low-temperature conditions [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the Physical Properties of Hydrate Sediments Recovered from the Pearl River Mouth Basin in the South China Sea: Preliminary Investigation for Gas Hydrate Exploitation

et al. 2017

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Laboratory based research on the physical properties of gas hydrate hosting sediment matrix was carried out on the non-pressurized hydrate-bearing sediment samples from the Chinese Guangzhou Marine Geological Survey 2 (GMGS2) drilling expedition in the Pearl River Mouth (PRM) basin. Measurements of index properties, surface characteristics, and thermal and mechanical properties were performed on ten sediment cores. The grains were very fine with a mean grain size ranging from 7 to 11 µm throughout all intervals, which provide guidance for the option of a screen system. Based on X-ray Computed Tomography (CT) and SEM images, bioclasts, which could promote hydrate formation, were not found in the PRM basin. However, the flaky clay might be conducive to hydrate formation in pore spaces. The measured sediment thermal conductivities are relatively low compared to those measured at other mines, ranging from 1.3 to 1.45 W/(m·K). This suggests that thermal stimulation may not be a good option for gas production from hydrate-bearing sediments in the PRM basin, and depressurization could exacerbate the problems of gas hydrate reformation and/or ice generation. Therefore, the heat transfer problem needs to be considered when exploiting the natural gas hydrate resource within these areas. In addition, the results of testing the mechanical property indicate the stability of hydrate-bearing sediments decreases with hydrate dissociation, suggesting that a holistic approach should be considered when establishing a drilling platform. Both the heat-transfer characteristic and mechanical property provide the foundation for the establishment of a safe and efficient production technology for utilizing the hydrate resource.

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“…Moreover, the velocity of TDeF is much faster than that of TInF. The temperature after TDeF decreases and approaches the equilibrium temperature corresponding to P well because of the endothermic nature of GH dissociation Table 1 Conditions of the hydrate-bearing sediment under the combination of depressurization and heating Liu et al, 2012).…”

Section: Evolutions Of the Pressure The Temperature And The Gh Satumentioning

confidence: 99%

A theoretical model for predicting the spatial distribution of gas hydrate dissociation under the combination of depressurization and heating without the discontinuous interface assumption

Liu

Zhang

2015

Journal of Petroleum Science and Engineering

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a b s t r a c tSpatial distribution of gas hydrate dissociation is essential in analyzing gas recovery and related potential hazards. This work develops a 1D model for predicting the spatial distribution of gas hydrate dissociation under the combination of depressurization and heating in the clay-silty sediments. Without assuming a discontinuous interface and a sudden decrease of pressure, the sediment is divided into a dissociated zone, a dissociating zone, and an undissociated zone. The dissociating zone is further separated into a heating subzone and a non-heating subzone. This work finds that (i) the thicknesses of the dissociating zone and the heating subzone as well as the propagation distance of the hydrate dissociation front are all linear with the square root of time, and the square root of hydrate dissociation time at any location is also linear with the distance between the location and the production well; (ii) the expansion velocity of the dissociating zone is about ninety times faster than that of the heating subzone, and a higher absolute permeability causes a faster expansion velocity of the dissociating zone, but barely affects the expansion velocity of the heating subzone; and (iii) the thickness of the heating subzone is less than 5% of the thickness of the dissociating zone in the latter stage of the hydrate dissociation process.

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The Characteristics of Gas Hydrates Recovered from Shenhu Area in the South China Sea

Cited by 171 publications

References 30 publications

Geochemical and magnetic signals for the mud volcano-induced methane seepage in the core sediments of Shenhu area, northern South China Sea

Geochemical and magnetic signals for the mud volcano-induced methane seepage in the core sediments of Shenhu area, northern South China Sea

Analysis of the Physical Properties of Hydrate Sediments Recovered from the Pearl River Mouth Basin in the South China Sea: Preliminary Investigation for Gas Hydrate Exploitation

A theoretical model for predicting the spatial distribution of gas hydrate dissociation under the combination of depressurization and heating without the discontinuous interface assumption

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