Rock and Fluid Models
The interaction between reservoir rock and in situ fluids is modeled with relative permeability and capillary pressure data. This chapter defines the three-phase oil relative permeability model used in WINB4D and its use in transmissibility calculations. It then presents additional details of the fluid property model after reviewing a few commonly used thermodynamic terms. 28.1 Three-Phase Relative Permeability Relative permeability curves are some of the most critical data in the simulator...
Introduction to WINB4D
WINB4D simulates isothermal, Darcy flow in up to three dimensions. It assumes reservoir fluids can be described by up to three fluid phases oil, gas, and water with physical properties that depend on pressure only. Gas is allowed to dissolve in both the oil and water phases. A feature unique to WINB4D is the inclusion of compressional velocity and acoustic impedance calculations. These reservoir geophysical calculations make it possible to track changes in seismic variables as a function of...
Initialization
It is important when making cross-section or 3D runs that the pressures in the model are correctly initialized. If not, phase potential differences due to gravity terms could cause fluid migration even though no wells are active. Consequently, a simple pressure initialization algorithm is used in WINB4D. It is reviewed below along with an option to correct pressures to a user-specified datum and an option to initialize saturations using gravity segregation. Consider a gridblock that may have a...
Chapter 31 Well Flow Index PID
Productivity index PI is defined as the ratio of rate Q to pressure drop AP, or PI Q AP, where AP Pe- Pw, Pe average reservoir pressure, and Pw wellbore bottomhole pressure BHP. From Darcy's Law for radial oil flow we can write PI as The meaning and units of all terms are given as follows The meaning and units of all terms are given as follows effective permeability md kro Kabs Some of the terms in Eq. 31.1 depend on time-varying pressure and saturation, while other factors change relatively...
Contents
1 Introduction to Reservoir Management 1 1.2 Management of Simulation Studies 4 1.3 Outline of the Text 6 Exercises 7 Part I - Reservoir Engineering Primer 2 Basic Reservoir Analysis 11 2.3 Decline Curve Analysis 16 Exercises 17 3 Multiphase Flow Concepts 19 3.4 Fractional Flow 26 Exercises 30 4 Derivation of the Flow 4.1 Conservation of Mass 31 4.2 Flow Equations for Three-Phase Flow 33 4.3 Flow Equations in Vector Notation 36 Exercises 37 5 Fluid 5.1 Buckley-Leverett Theory 39 5.3 Miscible...
53 Miscible Displacement
Buckley-Leverett theory treats the displacement of one fluid by another under immiscible, piston-like conditions. An immiscible displacement occurs when the displaced and displacing fluids do not mix. The result is a readily discernible interface between the two fluids. In a miscible displacement, the fluids mix and the interfacial tension approaches zero at the interface. A miscible displacement system is described by a convection-dispersion C-D equation. As an illustration, consider the...
Introduction to Reservoir Management
Reservoir modeling exists within the context of the reservoir management function. Although not universally adopted, reservoir management is often defined as the allocation of resources to optimize hydrocarbon recovery from a reservoir while minimizing capital investments and operating expenses Wiggins and Startzman, 1990 Satter and Thakur, 1994 Al-Hussainy and Humphreys, 1996 Thakur, 1996 . These two outcomes - optimizing recovery and minimizing cost - often conflict with each other....