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doi:10.2204/iodp.proc.346.205.2019

Introduction

Well log data is a powerful geological data type that enables direct comparison between laboratory sample measurements and in situ measurements made downhole. Large volumes of publicly available well log data have been generated by the Integrated Ocean Drilling Program (IODP) and its past phases. During these programs, samples have been drilled, logged, and collected from almost every geological setting around the world’s oceans (Goldberg, 1997); however, much of the data can go undiscovered and remain beyond the reach of geoscientists because of lack of knowledge that the data exist, lack of understanding of how to interpret the log data, and lack of software to use for interpretation.

To compound this problem, attaining the necessary skills to operate software packages for unpacking, analyzing, and interpreting log data can be expensive and time consuming. Although many log interpretation software providers offer software at subsidized prices, training in the operation of the software typically requires a fee. Further, after formal training is complete few opportunities exist for researchers to expand on the synthesized training schedule and its associated data. This can result in an environment with little easily accessible and appropriately formatted data from which researchers can gain experience.

The nature of downhole data is such that the data can be seemingly inaccessible to nonexperts. This, coupled with the fact that publicly available data sets are often not clean or well organized and sometimes are unconventionally labeled, can make using downhole data an unappealing and daunting task. One example of this complexity is Schlumberger’s online mnemonics list, which has >50,000 entries (Rider and Kennedy, 2011). Additional mnemonics can also be generated by modified acquisition processes and tools or by company-specific mnemonics, significantly expanding the length of this list.

In an attempt to provide a more accessible introduction to the use of downhole logging data, the Techlog training data set was developed using data acquired during Integrated Ocean Drilling Program Expedition 346.

Expedition 346, sailing in 2013, aimed to explore the climate system surrounding the marginal sea that borders the islands of Japan, the Eurasian continent, and the Korean peninsula. Primary expedition research focuses were on the following areas:

• Determining the effect of uplift of the Himalaya and Tibetan Plateau on the position of the Westerly Jet throughout the Pliocene and Pleistocene,
• Specifying timing and onset of orbital- and millennial-scale variability in the East Asian Summer Monsoon,
• Reconstructing paleoceanographic changes in productivity and bottom water circulation over the last 5 My, and
• Reconstructing the history of the Yangtze River discharge.

Although the Expedition 346 downhole logging program contributed to all expedition research aims, the primary contribution was to reconstruction of paleoceanographic changes in productivity by providing continuous data throughout the full depth of the hole.

Previous scientific drilling expeditions in the region, Ocean Drilling Program (ODP) Legs 127 (summer 1989) and 128 (fall 1989), covered a wide range of drilling targets in the marginal sea, such as volcanic massive sulfide deposits and deciphering the nature of basin extension (Tamaki, Pisciotto, Allan, et al., 1990; Ingle, Jr., Suyehiro, von Breymann, et al., 1990). Expedition 346, however, was the first expedition in the region to focus on paleoclimate systems (see the “Expedition 346 summary” chapter [Tada et al., 2015a]) and expand on objectives first targeted at ODP Site 798 (Ingle, Jr., Suyehiro, von Breymann, et al., 1990).

Data from Expedition 346 were chosen for the creation of a Techlog training data set because the expedition logged four of the seven drilled sites spread across a single basin with basin-wide lithofacies. High-quality data were generated for complete hole depths at all four sites, and these data were integral for achieving the Expedition 346 scientific objectives.

Intended for use with Schlumberger’s Techlog software, the training data set introduces users to Schlumberger’s Techlog package itself while simultaneously introducing basic downhole log data quality assurance/quality control and some of the ways that Techlog can be used to integrate multiple data sets and interrogate them together. The target end users are researchers who are less familiar with downhole log data sets; however, the data set should be useful to anyone who is unfamiliar with IODP log data acronyms and processing standards.

The data set was created to encourage an interdisciplinary approach by incorporating data from multiple methods of shipboard data acquisition, including downhole log data, core physical property data, discrete sample data, and core images.

The data set is designed to function without any latency on computers with the following minimum specifications:

• Intel Core i5 processor or equivalent (quad-core processor with a base frequency of 3 GHz), and
• 8 GB of RAM.

These are the same minimum system requirements for Schlumberger’s Techlog version 2017.2 and are lower than the recommended Techlog system requirement of 16 GB of RAM.

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