TABLE OF CONTENTS Reservoir deliverability is defined as the oil or gas production rate achievable from reservoir at a given bottom-hole pressure. It is a major factor affecting well deliverability. Reservoir deliverability determines types of completion and artificial lift methods to be used. A thorough knowledge of reservoir productivity is essential for production engineers.
Reservoir deliverability depends on several factors including the following:
Reservoir pressure
Pay zone thickness and permeability
Reservoir boundary type and distance
Wellbore radius
Reservoir fluid properties
Near-wellbore condition
Reservoir relative permeabilities
Reservoir deliverability can be mathematically modeled on the basis of flow regimes such as transient flow, steady state flow, and pseudo-steady state flow. An analytical relation between bottom-hole pressure and production rate can be formulated for a given flow regime. The relation is called "inflow performance relationship" (IPR). This chapter addresses the procedures used for establishing IPR of different types of reservoirs and well configurations.
When a vertical well is open to produce oil at production rate q, it creates a pressure funnel of radius r around the wellbore, as illustrated by the dotted line in Fig. 3.1a. In this reservoir model, the h is the reservoir thickness, k is the effective horizontal reservoir permeability to oil, ? o is viscosity of oil, B o is oil formation volume factor, r w is wellbore radius, p wf is the flowing bottom hole pressure, and p is the pressure in the reservoir at the distance
