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

Abstract

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.

Evolution of the Percolation Threshold in Muds and Mudrocks During Burial

“…The lines shown are power law fits for each bin, with the equation annotated; the solid line is for <40% clay sized, and the dashed line is for ≥40% clay sized. References for grain size data: Sawyer et al (), Ursa Basin; Wang et al (), South China Sea; Park et al (), Ulleung Basin; Daigle and Dugan (), Nankai Trough; Schneider (), resedimented Boston Blue Clay + silt and Nankai Trough + silt; Daigle and Piña (), Southern Alaska; Guiltinan et al (), resedimented quartz + kaolinite.…”

Influence of Reservoir Stimulation on Marine Gas Hydrate Conversion Efficiency in Different Accumulation Conditions

“…Value of R cv was calculated by subtracting the minimum x from the maximum x, with the following expression, R = x max − x min (12) r = R/x min (13) As shown in Table 10, r cv was decreased with increasing S H0 , and the r cv for case S H0 = 0.3 was the largest. This was because a higher S H0 had a lower effective permeability, and stimulation effect was more obvious in lower effective permeability condition, which led to a less difference of Q cv .…”

“…In this work, we considered the interaction of various factors and used the whole simulation experiments method (L 27 (3) 13 ) to analyze the significance of intrinsic permeability k, initial NGH saturation S H0 , and the stimulation effect (represented by cracks quantity N) and their interaction on NGH conversion efficiency of NGH deposits in the Shenhu area. Because these factors and their interactions both would affect NGH conversion efficiency, it was inaccurate to use a single variable approach to describe the influence rules of these three factors on NGH conversion efficiency; thus, a whole simulation experiment program which contained the interactions between these factors was necessary.…”

Non-Embedded Ultrasonic Detection for Pressure Cores of Natural Methane Hydrate-Bearing Sediments

“…At present, the exploration and development of natural gas hydrates in various countries in the world have promoted considerable research and numerous techniques [4][5][6][7]. With the development of natural gas hydrate sampling techniques, the detection and analysis of gas hydrate pressure cores become the bridge that connects hydrate exploration and exploitation [8][9][10]. Natural gas hydrate pressure cores reflect the reservoir characteristics and hydrate accumulation [11][12][13].…”