Petroleum Reservoir Engineering Practice

Chapter 9. Oil Reservoirs

9.1 Introduction

One of the important functions of a reservoir engineer is the estimation of oil-in-place (OIP) volumes, and the calculation of oil reserves thereafter. In this chapter, methods for estimating OIP volumes are presented for volumetric reservoirs, reservoirs with primary gas caps, and reservoirs with water influx. As was the case for gas reservoirs (Chapter 8), volumetric oil reservoirs are assumed to have constant hydrocarbon pore volume. Oil reservoirs are discovered at undersaturated or saturated conditions. As discussed in Chapter 4, an undersaturated oil reservoir has no initial gas cap at discovery, and reservoir pressure is at or above bubble point pressure. A saturated oil reservoir has a primary ...