Acoustic wave attenuation in the gas hydrate-bearing sediments of Well GC955H, Gulf of Mexico
Acoustic wave attenuation in the gas hydrate-bearing sediments of Well GC955H, Gulf of Mexico
复制标题
墨西哥湾GC955H井含天然气水合物沉积物中的声波衰减
DOI：
10.1007/s11001-017-9336-1
复制
发表时间：
2018-12
期刊：
影响因子：
--
通讯作者：
Priyank Jaiswal
中科院分区：
文献类型：
--
作者：
Jiliang Wang;Shiguo Wu;Jianhua Geng;Priyank Jaiswal
更好地了解含水合物沉积物中的波衰减对于改进海洋天然气水合物的地球物理定量化是必要的。在这里，我们比较了水合物饱和沉积物和水饱和沉积物在墨西哥湾GC955H站点的衰减行为，该站点在JIP LEG II探险期间进行了调查。在单极子波形上用中值频移法计算了含天然气水合物沉积物的纵波衰减。结果表明，细颗粒沉积物水合物充填裂隙中的低饱和度(<； )引起的P波衰减与充水裂隙情况相当。相反，由于水合物充填的粗粒沉积物孔隙中的高饱和度(>； 0.4)导致的P波衰减可达水饱和情况的三倍之多。相关分析表明，对于高饱和度的含气水合物砂岩段，纵波衰减随天然气水合物饱和度的增加而增大，而对于低饱和度的页岩段，纵波衰减与水合物饱和度的相关性较弱。结果表明，与细粒沉积物相比，P波衰减更有可能作为天然气水合物定量的地球物理指标。为了研究纵波在砂土中的行为，我们使用改进的LCAM模型，该模型考虑了颗粒边界粗糙度和喷流等物理因素，解释了水合物和饱和水的粗粒沉积物之间纵波衰减的差异。我们的结果为该区含天然气水合物沉积中的P波行为提供了进一步的地球物理证据。
A better understanding of wave attenuation in hydrate-bearing sediments is necessary for the improved geophysical quantification of marine gas hydrates. Here we compare the attenuation behavior of hydrate-saturated vs water-saturated sediments at site GC955H, in the Gulf of Mexico, which was surveyed during the JIP Leg II expedition. We compute the P-wave attenuation of the gas hydrate bearing sediments using the median frequency shift method on the monopole waveforms. The results show that P-wave attenuation due to low saturation (< 0.4) in hydrate-filled fractures of fine-grained sediment is comparable to that of the water-filled fracture case. On the contrary, P-wave attenuation due to high saturation (> 0.4) in the hydrate-filled pores of coarse-grained sediments can be up to as much as three times more than that of the water-saturated case. The correlation analysis shows that the P-wave attenuation increases with the increasing gas hydrate saturation for the highly saturated gas hydrate-bearing sand interval while the correlation of the P-wave attenuation and hydrate saturation is weak for low saturated gas hydrate-bearing shale interval. The results show that P-wave attenuation is more likely to be used as a geophysical proxy for gas hydrate quantification of highly concentrated coarse-grained sediment rather than for that of fine-grained sediment. To examine the P-wave behavior in sand, we use the improved LCAM model, which accounts for physical factors such as grain boundary roughness and squirt flow to explain the observed differences in P-wave attenuation between hydrate and water-saturated coarse-grained sediment. Our results provide further geophysical evidences for P-wave behavior in the gas hydrate-bearing sediments in the field.
登录
查看更多内容
影响因子：
4.2
作者：
S. Haines;P. Hart;T. Collett;W. Shedd;M. Frye;P. Weimer;R. Boswell
通讯作者：
S. Haines;P. Hart;T. Collett;W. Shedd;M. Frye;P. Weimer;R. Boswell
影响因子：
5.2
作者：
J. Dvorkin;M. Prasad;A. Sakai;D. Lavoie
通讯作者：
J. Dvorkin;M. Prasad;A. Sakai;D. Lavoie
影响因子：
--
作者：
G. Guérin;D. Goldberg
通讯作者：
G. Guérin;D. Goldberg
DOI：
10.4133/1.3614243
发表时间：
2011
期刊：
--
影响因子：
--
作者：
L. Baron;K. Holliger
通讯作者：
L. Baron;K. Holliger
影响因子：
2.8
作者：
J. Priest;A. Best;C. Clayton
通讯作者：
J. Priest;A. Best;C. Clayton