This monograph describes the practical aspects of planning, drilling, completion and operation of horizontal wells for the production of conventional crude oil, heavy oil, bitumen and natural gas. It provides the practising engineer with a broad background knowledge of the subject and an up-to-date summary of the latest in horizontal well technology. A major theme is the prediction of the performance of horizontal wells relative to that of conventional wells and the identification and evaluation of practical opportunities for the application of horizontal wells. Many field projects are described and their performances are compared to the models and concepts outlined. This book should enable engineers to reliably design and implement horizontal well projects. It integrates the diverse information into a consolidated, single reference. R.M. Butler is the author of "Thermal Recovery of Oil and Bitumen".