Shale, Siltstone and Mudstone in our Future

Arnold Bouma
Louisiana State University, Baton Rouge, LA

Shales, siltstones and mudstones represent about 2/3 of our sedimentary deposits. Only a small group of earth scientists work on them. The three terms can be divided into hundreds of sub-names. Recently the oil and gas industry became more interested in these muddy sediments because of possible use as seal, source rock and/or reservoir rock. The extreme variety within this sedimentary group does not enable us to fully understand which criteria are the most useful to serve anyone of those needs.

Great studies have been accomplished over time but some are published in unknown journals. Most industrial studies are directed to maximize the production of certain fields. Therefore we are not ready to indicate which parameters are required to produce certain information. Transport and deposition, detailed composition, geo-chemistry, engineering parameters, age, etc., are only a few aspects required to answer important questions. A major interactive and interdisciplinary research program will be required. Because we do not know which data are important we should start with a scientific approach before applicable directions, such as logging equipment and geophysical software, can be developed. Once an initial study is completed we can determine which directions make the next step. Universities and companies have to work together to develop a proper proposal. We should be aware of the age of the deposits, their densities, and the transport and depositional characteristics, before successful application can be obtained.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005