This dictionary is the result of the new era of Russian-American oil industry cooperation. During the course of translation work by the authors, many omissions and inaccuracies were noted in existing dictionaries. What began as a few pages of words and phrases for our internal use has evolved into what we believe to be the most comprehensive and accurate reference currently available.This is the first dictionary known to the authors which was developed in a joint effort by American and Russian petroleum professionals. Each term has been thoroughly discussed to provide the closest possible translation or an adequate communication of the concept.Primary emphasis of this dictionary is on petroleum engineering and its related subdivisions: drilling and completions, production engineering, and reservoir engineering. However, we have also endeavored to include the most often-used terms from petroleum geology, exploration geophysics, petroleum economics, and finance. We have drawn on many sources in the compilation of this book: research, technical literature, our own experience in field operations, and the collaboration of other petroleum professionals from both countries.For the first time, a dictionary has been made user-friendly through multiple listings. E.g., "drill collar" will be found under both the general headings "drill" and “collar." Thus, users of different perceptions are ensured convenience and quickest access to the object of the search.We would like to point out that this dictionary is not complete, nor is it intended to be so. We have intentionally restricted ourselves to the main terms used in the petroleum industry. The dictionary also includes a comprehensive listing of abbreviations and units’ conversions most frequently used in the petroleum industry.