Description

The main thrust of this two-volume set of books is to illustrate practical application of physical principles involved in primary recovery of oil and gas. Examples and procedures for solutions of common problems are covered. The first few chapters stress fundamentals and provide the basis for a thorough understanding of the data needed in reservoir engineering studies. Recovery mechanisms are introduced and steady-state flow concepts and equations are discussed. Volumetric calculations, material balance, and immiscible displacement processes are then presented. Individual chapters are devoted to the analysis of common drive mechanisms.

The introductory geology chapter discusses formation deposition, petroleum origin and migration, and the influence of geological background on formation properties. Porosity, permeability, and capillary pressure are treated in the rock properties chapter. Also covered are measurement methods and estimation techniques. The fluid properties chapter considers oil, gas, and water PVT properties. Sampling and laboratory measurement, as well as correlations, are included. A chapter is devoted to the determination of the original oil and/or gas in place through volumetrics (pore volume mapping) calculations. This includes "pay" studies, contour mapping, and the rigorous handling of varying properties.

Purous media flow theory is considered with attention to flow regime, flow geometry, and accompanying pressure distribution. Classical immiscible displacement theory is presented; the authors discuss the application of these techniques to waterflooding, water drive, reservoirs, and gas-cap drive reservoirs. For analysis of transient flow, simple techniques are given for prediction of stabilized deliverability, calculation of water influx, and interpolation of well testing data.

Material balance is discussed extensively for both oil and gas reservoirs. Attention is given to calculation of original hydrocarbon in place and to estimation of future production volumes. For water drive reservoirs, and aquifer model is required in conjunction with material balance. The Schilthuis, van Everdingen and Hurst, and Fetkovich models are considered. In combination drive reservoirs, material balance is used to determine "drive indices" and ultimate recovery.

Well test analysis is considered in two parts: deliverability testing and transient well testing. Theory is outlined, but emphasis is on application. Well test analysis is covered for both oil and gas wells. Although most of the discussion focuses on buildup tests, drawdowns are also considered. Other well testing topics include: formation damage, type curve matching, double porosity systems, linear flow (artificially fractured wells, long narrow reservoirs), and drillstem testing.

The reservoir simulation chapter illustrates the differences between classical reservoir engineering and reservoir stimulation. When variable properties, capillary pressure, and flow effects are included, the reservoir analysis problem becomes solvable only with a computer. There is a light discussion of the major topics of reservoir simulation.