Density structure of the pore-filling-type methane-hydrate reservoir at the Daini?Atsumi Knoll, Central Japan
Density structure of the pore-filling-type methane-hydrate reservoir at the Daini?Atsumi Knoll, Central Japan
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日本中部第二渥美丘陵孔隙充填型甲烷水合物储层的密度结构
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
T. Takayama
中科院分区：
文献类型：
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作者：
Kiyofumi Suzuki;Y. Komatsu;T. Fujii;T. Takayama
甲烷水合物沉积物的渗透率受沉积物岩性和孔隙中甲烷水合物饱和度的控制。因此，储层孔隙度的估计是重要的。然而，天然气水合物储层中的沉积物是软的;因此，尽管天然气水合物晶体具有沉积物强化作用，但钻井期间的干扰很容易降低数据质量。因此，沉积物测量特性的校正方法是非常重要的。我们获得了甲烷水合物储层内部和上方沉积物的密度（孔隙度）结构。由于密度测井中的不确定性，我们使用井径数据校正了测井，井径数据有时与密度呈负相关。校正后的密度数据与从压力岩心中回收的沉积物分析推断的结果吻合得很好。在这些样品上，我们对2004年和2012年的冷冻减压样品进行了压汞孔隙度测定，并根据常规岩心的机载多传感器岩心测井仪（MSCL）数据确定了密度，特别是在甲烷水合物富集区（MHCZ）。我们的研究结果使我们能够将大尼-厚见穹丘上的天然气水合物稳定带（GHSZ）之上的沉积物划分为四个带，带的边界对应于相的边界。这意味着沉积相不仅对岩性产生强烈影响，而且对密度（孔隙度）等物理性质也产生强烈影响。
The permeability of methane hydrate sediments is controlled by the lithology of the sediments and the saturation of methane hydrate in pore spaces. Thus, estimates of porosity in the reservoir are important. However, sediments in gas hydrate reservoirs are soft; thus, disturbances during drilling easily degrade the quality of data, despite the sediment-reinforcing effects of gas-hydrate crystals. Hence, methods for correcting the measured properties of sediments are quite important. We obtain the density (porosity) structure of sediments within and above the methane hydrate reservoir. Due to uncertainties in the density logs, we corrected the logs using borehole caliper data, which is sometimes negatively correlated with density. The corrected density data agreed well with results inferred from analysis of sediments recovered in pressure cores. On these samples, we conducted mercury injection porosimetry on frozen depressurized samples from 2004 and 2012 and also determined density from the onboard multisensor core logger (MSCL) data on conventional cores, especially in methane hydrate concentrated zone (MHCZ). Our results allow us to divide the sediments above the gas hydrate stability zone (GHSZ) on Daini-Atsumi Knoll into four zones.The zone boundaries correspond to facies boundaries. This implies that the sedimentary facies strongly influenced not only the lithology, but also physical properties such as density (porosity).