TABLE OF CONTENTS Well deliverability is determined by the combination of well inflow performance (see Chapter 3) and wellbore flow performance (see Chapter 4). Whereas the former describes the deliverability of the reservoir, the latter presents the resistance to flow of production string. This chapter focuses on prediction of achievable fluid production rates from reservoirs with specified production string characteristics. The technique of analysis is called "Nodal analysis" (a Schlumburger patent). Calculation examples are illustrated with computer spreadsheets that are provided with this book.
Fluid properties change with the location-dependent pressure and temperature in the oil and gas production system. To simulate the fluid flow in the system, it is necessary to "break" the system into discrete nodes that separate system elements (equipment sections). Fluid properties at the elements are evaluated locally. The system analysis for determination of fluid production rate and pressure at a specified node is called "Nodal analysis" in petroleum engineering. Nodal analysis is performed on the principle of pressure continuity, that is, there is only one unique pressure value at a given node regardless of whether the pressure is evaluated from the performance of upstream equipment or downstream equipment. The performance curve (pressure-rate relation) of upstream equipment is called "inflow performance curve"; the performance curve of downstream equipment is called "outflow performance curve." The intersection of the two performance curves defines the operating point, that is, operating flow rate and pressure, at the specified node. For the convenience of using pressure data measured normally...
