Characterization of the Degree of Fracturing and the Nature of Fracture Alteration from MCS Logging Data at Site 395A, 418A and 504B

该项目分析了现有的钻孔声波测井数据 以获得高分辨率的速度， 衰减估计，从其中推断的程度 海洋地壳的断裂这很重要，因为流体流动 主要受断裂控制：在年轻时， 海洋地壳数据表明，浅地壳含有许多 开放的裂缝构成了一个低压含水层， 高渗透性。随着时间的变化，产品密封这些 降低渗透性和流体流动的裂缝 戏剧性地。通过整合改进的速度数据和新的 用井中电视和伽马射线估算衰减 测井，裂缝间隔将被定位和表征为 打开或密封。变更性质的变化 密封裂缝中的材料将从 速度和衰减资料与其它测井资料相结合 数据和岩心地球化学结果。光圈的变化 或开放裂缝的渗透性将从 衰减数据。

This project analyzes existing sonic log data from bore holes in the ocean floor to obtain high resolution velocity and attenuation estimates from which to infer the degree of fracturing in ocean crust. This is important because fluid flow in the crust is controlled primarily by fractures: in young ocean crust data indicate that the shallow crust contains many open fractures which constitute an underpressured aquifer of high permeability. With time alteration products seal these fractures which reduces the permeability and fluid flow dramatically. By integrating improved velocity data and new attenuation estimates with borehole televiewer and gamma ray logs, fractured intervals will be located and characterized as open or sealed. Variations in the nature of the alteration material in the sealed fractures will be indentified from velocity and attenuation data in conjunction with other log data and core geochemical results. Variations in the aperture or permeability of the open fractures will be identified from the attenuation data.