During the past twenty years nuclear well logging has grown to become one of the most important peaceful applications of the principies of nuclear physics. Nuclear logs are used to resolve a variety of exploration and production problems ip both cased and uncased wells and in many areas have provided information not obtainable by other means. Nevertheless, developments have been slow, and as a consequence nuclear logging must still be regarded as being in its infancy. Many of the most promising methods have yet to be tried out experimentally in a borehole, and methods which have been in use for many years are continuously undergoing improvements. This paper reviews the development and principal applications of nuclear weil logs. An aim is to evaluate critically the status of nuclear well logging in general and because of its fundamental aspects, gamma-ray logging in particular.
Durant les vingt dernières années les diagraphies nucléaires sont devenues l'une des applications pacifiques les plus importantes des principes de la phyeique nucléaire. Les diagraphies nucléaires ont permis de résoudre un nombre de problèmes d'exploration et d'exploitation dans des forages tubés aussi bien que non tubés et, dans de nombreuses régions, elles ont fourni des renseignements impossibles à obtenir par d'autres moyens. Toutefois, comme le développement de la méthode a été lent, la diagraphie se trouve encore à ses débuts. Plusieurs méthodes parmi les plus prometteuses doivent encore être mises à l'épreuve dans des forages, et des méthodes, en usage depuis de nombreuses années, sont constamment améliorées. L'article ci-dessous fait la revue du développement et des applications principales des diagraphies nucléaires. Son objet est d'évaluer d'une façon critique l'état actuel des diagraphies nucléaires en général et, étant donné leur importance fondamentale, des diagraphies gamma en particulier.
According to a recent estimate by the United States Atomic Energy Commission, nuclear well logging techniques are saving the petroleum industry between 16 and 24 millions of dollars annually. While we cannot accept these figures even as crude estimates, because we feel that it is impossible (and also rather meaningless) to place a dollar value on any single operation occurring in the history of an oil well, we will concur that nuclear logging is, and should continue to be for many years, one of the most important peaceful applications of the principles of nuclear physics.
Since the commercial introduction. of nuclear logging methods to the petroleum industry nearly twenty years ago, the utilization of nuclear logs has steadily increased to the point where today at least one nuclear device is run in the majority of the wells drilled in the search for
