Collaborative Research: Shear Wave Studies of Hydrate Ridge, Oregon Continental Margin, During Planned ODP leg 198

合作研究：计划 ODP 第 198 段期间俄勒冈州大陆边缘水合物脊的剪切波研究

• 批准号: 0002487
• 负责人: Nathan Bangs
• 金额: $ 38.29万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0002487&HistoricalAwards=false
• 关键词: Collaborative; Research; Shear; Wave; Studies

Pecher 00-02487Trehu 00-02410Recommended project is for a series of seismic experiments to be conducted from boreholes during Ocean Drilling Program (ODP) Leg 198 to map occurrences of gas hydrate and free gas in sediments on Hydrate Ridge offshore Oregon. These experiments will geophysically extend observations from direct core description, direct core measurement, and borehole logging into the surrounding sediments, thereby provide 3-D coverage of inferred gas hydrate and free gas occurrence over a much larger sediment volume. The experiments include: 1) constant-offset vertical seismic profiling (VSP) with a fixed source receiver, coordinated with zero-offset VSP's, which will result in vertically continuous shear-wave velocity (Vs) profiles; 2) walkaway VSP's, acquired by shooting over the borehole with a second ship to a receiver at fixed depth within the borehole, thereby acquiring high-quality Vs and compressional wave (Vp) data to calibrate rock physics models of gas-hydrate bearing sediments; 3) deployment of ocean bottom seismometers in a dense array around one of the boreholes for dense 3-D seismic coverage to examine an area of inferred focused fluid flux and its relationship to a gas hydrate cap; and 4) using the ODP Advanced Piston Corer (APC) as a seismic source during piston deployment for a larger array of measurements using the OBS array. These geophysical results will be directly tied to drilling results to constrain relationships between fluid flux, free gas, and hydrate formation in a convergent margin setting.***

Pecher 00-02487 Trehu 00-02410建议项目是在大洋钻探计划第198段期间从钻孔进行一系列地震实验，以绘制俄勒冈州近海水合物山脊沉积物中天然气水合物和游离气的赋存状态。这些实验将从地球物理的角度将观测从直接岩心描述、直接岩心测量和钻孔测井扩展到周围的沉积物，从而在更大的沉积物体积上提供推断的天然气水合物和游离气赋存状态的三维覆盖。实验包括：1)定源距垂直地震剖面(VSP)，配合零偏移距VSP，得到垂直连续的横波速度(VS)剖面；2)走走VSP，用第二艘船在井眼上方激发到井内固定深度的接收器，从而获得高质量的VS和纵波(Vp)数据，以标定含天然气水合物沉积物的岩石物理模型；3)在其中一个钻孔周围以密集阵列部署海底地震仪，以进行密集的三维地震覆盖，以检查推断的聚焦流体通量区域及其与天然气水合物盖的关系；以及4)在活塞部署期间使用ODP型高级活塞取样器(APC)作为震源，以使用OBS阵列进行更大阵列的测量。这些地球物理结果将直接与钻井结果捆绑在一起，以约束收敛边缘环境中流体流量、游离气和水合物形成之间的关系。*