The scientific results of the cruise are initially presented in the Initial Reports (IR) volume, which is organized by site. The Logging Staff Scientist is responsible for presenting the results of any downhole measurements made during the leg. Any site for which logging operations are conducted requires a chapter on downhole measurements. In this section the Logging Scientist will:

  1. Present the operational details for the site. If more than one toolstring is run, then the operations will be summarized in a table organized by toolstring with the following information: start and stop time, logging speed, pipe depth, mudline measured depth, interval logged for each pass, and the tools on the string. The text will also contain general information about the site, such as total penetration, core recovery, muds that were circulated etc. Finally, the conditions of the hole during logging will be discussed, as well as any obstacles or difficulties encountered which affect data quality.
  2. Present the results of the logging. This section is usually similar to the data results of a paper in which log data are presented (in plot form) and the pertinent features described. The presentation of results will be tailored to the science of the leg and integrated as much as possible with the results from other groups (physical properties, sedimentology, biostratigraphy, magnetics, geochemistry, etc.). Frequently a summary figure containing all of the log curves, caliper curve, stratigraphy, sedimentology, etc., is presented. This is then followed by a breakdown of each of the records describing them in the context of the other data, including plots where necessary.
  3. Discuss the detailed comparisons with other data, core-log comparisons, and definitions of stratigraphic intervals. Finally, the results of any analysis or scientific highlights of the logs will be presented. This section may be included in each of the tool results sections if it is not significant enough to merit an independent section.


Occasionally, the Logging Staff Scientist will collaborate with other shipboard scientists in producing the seismic stratigraphy chapter of the Initial Reports volume. Seismic sequence analysis is usually outlined in this chapter to describe the structural boundaries between layers of different ages and to provide scientific context for the proper interpretation of drilling and logging results. The seismic profiles included in this chapter are usually collected during pre-cruise site surveys; occasionally, seismic profiles from industry sources are also available. The quality and density of the seismic data are usually a function of the scientific objectives of the drilling leg. For legs on which seismic stratigraphic sequence analysis is most important, multichannel seismic (MCS) data are frequently available; for the others, single-channel seismic (SCS) data are usually the norm. The specifications for the seismic data are usually given in this chapter, including acquisition and processing.

On certain legs -- such as those on which vertical seismic profiling is performed -- the Logging Staff Scientist will be more involved in the collection and interpretation of seismic profiles, and thus will have a more active role in the production of the stratigraphy chapter of the IR volume.

Geological information derived from the stratigraphic sequences is used to define in detail the geological or tectonic setting of the leg, to design the leg operation, and to tie seismic boundaries with core and log depths, both during the leg and post-cruise. Proper use of the results of seismic sequence analyses can help in the integration of core, log and seismic data and can enhance the spatial interpretation of high-resolution profiles of structural, physical, and chemical properties from the core and log data.


The purpose of the explanatory notes chapter of the IR volume is to provide the reader with the technical and operational background for the wireline logging operations conducted during the leg. Although there are an infinite number of ways to present this material, a typical downhole logging section of the Explanatory Notes would contain the following sections:

    Introduction
    This section should introduce the reader to what wireline logging is and how it is conducted (e.g. the in situ measurement of physical, chemical, and structural properties). It is tailored to the science relevant to the leg under discussion and may include general principles of how these measurements can contribute to the scientific goals of the leg. Other points frequently included are:

    • The particular advantages of wireline measurements and how they complement the other types of analysis that will be made.
    • Past examples of applications and pertinent references.
    • Information about who provides the logging services (e.g. ODP Logging Services & Schlumberger) and the role that each plays.

    Operations
    This section will provide operational details for the reader. Some typical topics are as follows:

    • Hole is flushed with fluid.
    • Wiper trip is conducted.
    • Pipe pulled to logging depth (e.g., 90m).
    • Tools assembled and lowered on 7 conductor cable.
    • WHC employed.
    • Details on data acquisition system and satellite transfer methods.

    Because the operations section is site specific, it is possible to cover the general operational techniques in the introduction, specific operational details in the site chapter, and omit this as a separate section.

    Logging Tools
    This section will introduce the tools and how they were combined during the leg. Usually, figures and tables are employed to present the information more coherently. Typically, a figure of the toolstrings employed on the leg and a table of the tools and their depth of investigation, sample interval, and vertical resolution are presented in this section. In the text, the names of the tools, their acronyms, and the measurements they make are introduced, and the theory behind the measurements may be summarized. This will essentially amount to a paragraph about each tool. If new tools were used or conventional tools employed in an unconventional way, then a more detailed explanation of the tool and the way it makes its measurements will be provided.

    Data Quality
    Any environmental (borehole conditions, excessive heave etc.) or technical problems encountered on the leg will be discussed here in the context of how they affect data quality.

    Data Processing
    This section is somewhat optional, but it is usually included, especially if the logging operation employed new tools, new techniques, or data were applied in new ways. The basics of depth shifting and correlation between the passes are briefly presented. Then details of how particular estimates are derived from the data will be given. For example, these may include the onboard generation of a magnetostratigraphy (using the GHMT) or clay typing (using natural gamma ray and photoelectric effect).

The above sections are meant to provide guidelines for the type of information to be conveyed in the Explanatory Notes. As the specific operations and science of each leg is different, it may be beneficial to refer to previous examples of explanatory notes from legs with similar scientific objectives and/or tool deployments (e.g. 162,167,172, 175 for paleoceanography, or 118, 140, 148 or 176 for hard rock environments).


The preliminary report is meant to supply operational details and highlights of the data which is recovered. Operational details that are usually presented include: BHA depth, tools used and depths logged during each pass, number of passes, problems encountered, highlights of the recovered data and its potential utility (e.g., potential for core-log integration, cyclicity related to climate, good magnetics that allow reversal stratigraphy etc. ).
 

Data
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Logging
Operations
Stuck/Lost
Tool Policy
Shipboard
Reports