Significant Contributions in Formation Evaluation and Well Testing

Formation evaluation and well testing are subjects that have the reservoir in common, but have distinctly different technical approaches. Therefore, this review has been organized to present the technical approaches separately; first, formation evaluation, then well testing. It is not surprising that these subjects have different literature development. Formation evaluation literature started with the first records of Drake's well in 1859, whereas well testing technology has developed more recently and more nearly parallels the 25-year life span of the Journal of parallels the 25-year life span of the Journal of Petroleum Technology. Petroleum Technology. Formation Evaluation

In a general sense, formation evaluation can be defined as the science and the art, in that order, of economic evaluation of natural resources occurring in earth formations. For the purposes of this paper, however, the definition will be confined to the evaluation of petroleum reservoirs. In this context, formation evaluation may be considered to include all coring, well logging, mud logging, testing, and sampling procedures. As the demand for energy resources has increased, the science of formation evaluation has responded to the challenge, with technology advancing at such a rapid rate that textbooks in this field are usually outdated before they can be printed. The increase in number of publications and number of local, national, and international meetings each year reflects the unparalleled growth in this field. Research in petrophysics, the transfer of technology from related petrophysics, the transfer of technology from related scientific disciplines, and the extensive use of computers have contributed significantly to establishing formation evaluation as an earth science. However it must be emphasized that this field is still very much a growing science, constantly stretching its frontiers. Thus, where science and technology end, the art (educated intuition) must take over. Early developments in formation evaluation are thoroughly documented in a review article by Leonardon. A recent list of significant contributions to formation evaluation through 1969 has been compiled by the SPE-AIME Reprint Series Committee as part of the reprint booklet on well logging. This committee succeeded in reducing the vast literature on formation evaluation to a relatively few key papers, which have been collected into a single volume of slightly more than 400 pages. This significantly increased the access to relevant and up-to-date information in this field. More recently, Jorden forecast future trends in formation evaluation for the next two to three decades. We do not attempt here an exhaustive review of the above-cited selected literature. Instead, we have tried to provide a general and, we hope, informative review and to refer the reader to pertinent literature for further details.

JPT

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