ABSTRACT

Specific factors which affect electrical logging are discussed and related to two different types of the Eocene Wilcox.

In the shallow Wilcox, exemplified by the Natchez trend, use of the induction log and MicroLog solves most of the logging problems.

In the other type, the deep Wilcox, the response of various logging devices depends to a great extent on the type of drilling mud and the invasion effects thereby produced. Suggestions are made which will improve the efficiency of certain logging methods and will permit satisfactory qualitative interpretation.

The Wilcox formation of the Gulf Coastal embayment exhibits a wide range of special conditions which affect both production practices and the evaluation of electrical surveys. Our purpose is to study these conditions as they are related to electrical logging problems.

In general, the Eocene Wilcox consists of a very thick series of shales, shaly sands and sands, together with many lignite beds. To describe this series in more detail requires that this formation be divided into at least two types.