Gas Reservoir Engineering provides the undergraduate as well as the graduate student with an introduction to fundamental problem solving in gas reservoir engineering through practical equations and methods. Although much oil well technology applies to gas wells, many differences exist. This book helps students understand and recognize these differences to enable appropriate handling of gas reservoir problems. Natural gas production has become increasingly important in the U.S., and the wellhead revenue generated from it is now greater than the wellhead revenue generated from oil production. Because this trend eventually will be followed worldwide, we feel that it is important to emphasize gas reservoir engineering courses at the undergraduate level and to have a textbook devoted to this purpose. This book also serves as an introduction to gas reservoir engineering for graduate students and practicing petroleum engineers. Although much of the technology for oil wells applies to gas wells, there are still many differences. It is important to learn these differences and to have a good, fundamental background in how to recognize and handle them. We have tried to provide practical equations and methods while emphasizing the fundamentals on which they are based. We have not attempted to be complete in the sense of presenting the best-known solution(s) to all problems in this area of technology. In many cases, we didn't even present the problem, much less a solution. Instead, we concentrated on fundamentals and hope to have made the literature in gas reservoir engineering more accessible both now and in the future. If you don't find your favorite topic in the table of contents or in the index, it simply didn't make our short list of fundamentals that we believed to be key parts of the literature.