Electrical well logging was introduced to the oil industry over a half century ago. The first log was recorded on September 5, 1927, in a well in the small oil field of Pechelbronn, in Alsace, a province of northeastern France. This log, a single graph of the electrical resistivity of the rock formations cut by the borehole, was recorded by the “station” method. The downhole tool (called a sonde) was stopped at periodic intervals in the borehole, measurementsw ere made, and the calculated resistivity was hand-plotted on a graph. This procedure was repeated from station to station until the entire log was recorded.<...>

Ideas that karst can develop at depth without direct genetic relationship to the surface have a long history, but remained on the periphery of karstological thinking, not influencing the traditional paradigm of karst until the last 25 years. More attention to hypogene karst since 1990, and particularly the dramatic burst of studies in this field during the last decade, has changed our notion of hypogene karst from a curiosity to one of the fundamental categories of karst, at least of compatible importance with more familiar epigene karst. <...>

Cave geology, as treated in this book, concerns not only the geology and origin of caves, but also related aspects such as hydrology, geochemistry, and microbiology. All cave sciences are combined in the field otspeteolag)'. More than any other science, speleology is closely tied to exploration and adventure. Anyone can participate in it.

The Niger Delta region is attractive to petroleum exploration companies primarily because of its prolific hydrocarbon wealth. Since the first commercial discovery of hydrocarbon from the Oloibiri Field in 1965 by Shell–BP Petroleum Development Company, the Niger Delta region has been an area of intensive oil and gas exploration activity. The vast amount of subsurface material and data accumulated over the past six decades, have hitherto been proprietary to the different operating companies. This book Cenozoic Foraminifera and Calcareous Nannofossil Biostratigraphy of the Niger Delta is the first attempt to harmonize, in a single volume, the biostratigraphic data of the individual companies that operate in the region <...>