| Over the last four years, ODP Logging Services has undertaken a major effort to create an easily accessible, on-line database of the log data collected by the Ocean Drilling Program. Currently, the ODP Log Database contains the majority of the log data collected by ODP, and in the future will provide access to all ODP log data. It can be accessed and searched through the internet, providing a convenient method for downloading large amounts of data, as well as educational and technical information about the applications of log data to scientific problems. The ODP Log Database can be accessed at:
http://www.ldeo.columbia.edu/BRG/ODP/DATABASE/
The ODP Log Database provides access to log data 24 hours a day, 7 days a week from any computer in the world. Using the database, a user has the ability to search by leg, hole, location, ocean/sea, or tool:
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The Data Search screen on the ODP Logging Services web site.
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The Search Results screen. Data are organized by hole number.
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A keyword search will soon be available as well. This feature will greatly enhance the search capability of the database. For example, scientists will be able to search for all holes where basement was penetrated, or search for all the holes where fluid processes were an important objective.
The log database is useful not only for scientific research, but also for cruise planning. If a proponent is writing a proposal for drilling in an accretionary prism, for instance, the keyword feature can be used to search for all holes logged in accretionary prisms and determine what tools were used in each. The links to the on-line logging summaries would reveal that the traditional coring and logging techniques used in the early cruises were not very successful. Recent cruises (such as Legs 170 and 171A) that used logging-while-drilling (LWD) techniques, however, delivered very satisfactory results. Links are also available to a "Guide to Logging" section, where in-depth information on the tools is provided, and to "Proponent’s Helper," a section that provides assistance in completing the required site forms.
While the log database is an important asset to most ODP research, its value is greatly enhanced when the data can be integrated and compared with core data. For this reason, a link is provided from each listing of log data collected in a hole to the corresponding core data set at the TAMU web site.
The ODP log database consists of profiles and images of geophysical measurements – e.g., density, gamma ray, porosity, resistivity, and acoustic properties – recorded as a function of depth in a drill hole. There are two basic data formats currently available on-line: ASCII and GIF. ASCII can be opened in a variety of applications, although spreadsheet and graphing programs are most often used. Image data, such as the FMS, are provided as GIF files. The easiest way to view these files is in a web browser such as Netscape Navigator or Internet Explorer. They can also be imported into graphics programs or included in word processing documents.
Along with these files, the log database contains explanatory documentation and log summary plots. The documentation provides an overview of operations for each hole as well as information about processing procedures and quality control. The file dictionaries provide a list of data file names for each hole and the corresponding data type contained within it. The log summary plots show various types of log data and core recovery plotted versus depth. They are available only for the more recent legs (Leg 155 and later).
For one year after the drilling leg, log data from the leg can be accessed by members of the shipboard scientific party only; a username and password unique to each leg are distributed about two weeks after the leg. After a one year moratorium the password is lifted and the data become available to the rest of the scientific community. |
