Petroleum Production Systems

Chapter 3. Production from Two-Phase Reservoirs

3.1. Introduction

The performance relationships presented in Chapter 2 were for single-phase oil wells and, while gas may come out of solution after oil enters the wellbore, the use of those relationships does not consider free gas to be present in the reservoir. Expansion of oil itself as a means of recovery is a highly inefficient mechanism because of the oil’s small compressibility. It is likely that even in the best of cases (the issue is addressed in Chapter 10), if the bottomhole pressure is above the bubble-point pressure, as is the case for heavy oil, a very small fraction of the original-oil-in-place would be recovered. Therefore, in most oilfields, oil will be produced along with free ...