Gas Hydrate Identification of Parametic Array Sub-bottom Data by Coherence Attribute Analysis

EasyChair Preprint 1434

Abstract

Nowadays, sub-bottom profile is also a effective method for detecting the shallow sediments. It is widely used in submarine geological structure detection, and marine engineering. The parametric array sonar greatly improved the detection resolution and suppress noise. These technical advantages, determine the parametric sonar is suitable for shallow sediment detection.

Coherence technique is known as one of the most important breakthroughs in the field of seismic exploration in recent decades. Compared with the previous method, coherence technique can more clearly identify faults and stratigraphic features. Zones with low coherence values are closely related to strata with poor continuity, such as faults, special lithologic structure boundaries, and so on.

The parametic array sub-bottom data used in this study is collected from gas hydrate potential area of the East China Sea. The 3D data volume was formed by mesh construction and interpolation smoothing. After calculating, the coherence attribute data volume is obtained. The profiles clearly reflect the discontinuity of sub-bottom stratum. It is considered that these discontinuities would be related to blank zone. it is suggested that the sedimentation around blank zone may be different from normal sub-bottom. In addition, the largest continuity interruption occurs at the gas chimney zone, which may be related to free gas charge.

The study area is roughly divided into two parts by the trough from northwest to southeast. The elevation of northwest is higher than the southeast. Comparing coherence slices of different depth, there is good correspondence between the low coherence regions and the blank zones, especially the gas chimney areas. The boundaries of anomalous areas are significantly more clear than conventional seismic data. Considering the relationship between gas chimney and hydrate, the gas hydrate can be well identified.

Keyphrases: Coherence Technique, Parametic Array, Sub-bottom Profile, gas hydrate

@booklet{EasyChair:1434,
  author    = {Rui Yang and Shanshan Chen and Huaning Xu and Jun Liu and Zhonghui Yan and Hong Liu and Xiaojie Wang and Xinxin Liu and Jiajia Yang and Jiangxin Chen and Hailong Li and Yuanyuan Huo and Panke Qin and Guangxuan Chen and Nengyou Wu},
  title     = {Gas Hydrate Identification of Parametic Array Sub-bottom Data by Coherence Attribute Analysis},
  howpublished = {EasyChair Preprint 1434},
  year      = {EasyChair, 2019}}