Characterizing 3D fracture networks and modeling wave propagation beneath Southern Hydrate Ridge using data from the existing 3D seismic site survey

支持者将挖掘2000年从水合物山脊收集的二维地震数据，以更好地确定山顶地区下方的裂缝网络和管道，这些裂缝网络和管道涉及将天然气输送到天然气水合物稳定带并通过该稳定带。为实现这一目标，将采取的任务包括：1)对叠前地震反射数据采用确定性静校正，以校正潮汐引起的水深变化；2)采用不同的方法对叠前数据进行入库和内插，以改善地震数据切片的南北连续性；3)建立综合了OBS走时层析成像、VSP和声波测井结果的三维速度模型；4)对经潮汐校正和内插的反射数据进行三维叠前深度偏移；以及5)使用单个炮点和中点道集的有限差分合成地震图对波场进行正演模拟，以更好地了解海底散射引起的幅度影响，并将它们与次表层衰减引起的影响分开。该项目的潜在更广泛影响包括为规划目前正在开发的几个大型项目提供重要的背景信息。它还将为一位有前途的年轻女性博士后提供培训。活跃的海底喷口系统的地下管道的3D图像也将有助于将这项研究的兴奋传递给普通公众。

The proponents will mine 2-D seismic data collected in 2000 from Hydrate Ridge to better define the fracture networks and conduits beneath the summit region that are involved in transporting gas into and through the gas hydrate stability zone. Tasks to be undertaken to achieve this goal include 1) incorporation of a deterministic static correction to prestack seismic reflection data to correct for changes in water depth due to tides; 2) a different approach to binning and interpolating the prestack data to improve north-south continuity of slices through the seismic data; 3) construction of a 3D velocity model that integrates results from OBS travel-time tomography, VSPs, and sonic logging; 4) 3D pre-stack depth migration of the tide-corrected and interpolated reflection data; and 5) forward modeling of the wavefield using finite difference synthetic seismograms of individual shot and midpoint gathers to better understand amplitude affects due to seafloor scattering and separate them from those due to attenuation in the subsurface.The potential broader impacts of this project include providing important background information needed for planning several large programs that are currently under development. It will also provide training for a promising young female post-doc. The 3D images of the subsurface plumbing of an active seafloor vent system will also be useful for transmitting the excitement of this research to the general public.