Month: June 2023

The rate of flow of gas expressed in standard cubic feet per day is the same at all cross sections in a steady-state, linear system. However, because the gas expands as the pressure drops, the velocity is greater at the downstream end than at the upstream end, and consequently, the pressure gradient increases toward the downstream… Continue reading Linear Flow of Compressible Fluids, Steady State

The equation for flow of slightly compressible fluids is modified from what was just derived in the previous section, since the volume of slightly compressible fluids increases as pressure decreases. Earlier in this chapter, Eq. (8.3) was derived, which describes the relationship between pressure and volume for a slightly compressible fluid. The product of the flow… Continue reading Linear Flow of Slightly Compressible Fluids, Steady State

Figure 8.4 represents linear flow through a body of constant cross section, where both ends are entirely open to flow and where no flow crosses the sides, top, or bottom. If the fluid is incompressible, or essentially so for all engineering purposes, then the velocity is the same at all points, as is the total flow… Continue reading Linear Flow of Incompressible Fluids, Steady State

Now that Darcy’s law has been reviewed and the classification of flow systems has been discussed, the actual models that relate flow rate to reservoir pressure can be developed. The next several sections contain a discussion of the steady-state models. Both linear and radial flow geometries are discussed since there are many applications for these… Continue reading Steady-State Flow

Reservoir flow systems are usually classed according to (1) the compressibility of fluid, (2) the geometry of the reservoir or portion thereof, and (3) the relative rate at which the flow approaches a steady-state condition following a disturbance. For most engineering purposes, the reservoir fluid may be classed as (1) incompressible, (2) slightly compressible, or… Continue reading The Classification of Reservoir Flow Systems

In 1856, as a result of experimental studies on the flow of water through unconsolidated sand filter beds, Henry Darcy formulated the law that bears his name. This law has been extended to describe, with some limitations, the movement of other fluids, including two or more immiscible fluids, in consolidated rocks and other porous media.… Continue reading Darcy’s Law and Permeability

The material balance equations for each of the four reservoir types defined in were developed. These material balance equations may be used to calculate the production of oil and/or gas as a function of reservoir pressure. The reservoir engineer, however, would like to know the production as a function of time. To learn this, it is… Continue reading Introduction