Formation Evaluation: Status And Developments
Authors: Evans Hilton B. , Pickett G.R. 
Published: December 2007

This paper was prepared for the 40th Annual California Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in San Francisco, Calif., Nov. 6–7, 1969. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.
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Abstract
The current status and apparent trends in formation evaluation are reviewed. There are at present well over two dozen borehole present well over two dozen borehole measurements available for formation evaluation encompassing cuttings samples, cores, borehole fluid logs, wireline logs and productivity and fluid flow tests. Some twenty major applications in petroleum engineering are realized by use of petroleum engineering are realized by use of this array of measurements. The predominant application continues to be estimation of recoverable hydrocarbon volumes, but other important applications in connection with exploration, exploitation, and well completion are also realized.
Some of the most interesting and useful of the innovations introduced include (1) nuclear magnetism logs for determining "movable" reservoir fluids, (2) activation analyses using the pulsed-neutron system to define lithology and pulsed-neutron system to define lithology and fluid saturation, (3) the "Borehole Televiewer", a wireline system for acoustically "photographing" the casing or borewall face, and (4) "ULSEL", the very long spaced electrical device for detecting anomalies in resistivity or conductivity far removed from the normal zone investigated by modern log suites.
Recent interpretive advances include techniques for quantitative determination of mixed lithology components, application of computer technology to interpretation problems and derivation of statistical techniques for determining many parameters of interest in formation evaluation, including the hydrocarbon content of potential reservoirs.

Introduction
One objective of this paper is to provide petroleum engineers with a generalized petroleum engineers with a generalized perspective of the devices, techniques, and parameters perspective of the devices, techniques, and parameters which are the basis for formation evaluation measurements in boreholes. Therefore, we shall attempt to survey the status of formation evaluation applications and describe the trends in research.
Any discussion encompassing the field of formation evaluation is necessarily nonspecific in nature. Therefore, when details are too extensive to be appropriately covered or are unavailable, generalizations must suffice. Specifics, however, are readily available in individual papers concerning the topics mentioned in this review; references are provided.