The isothermal compressibility for a substance is given by the following equation: where c = isothermal compressibility V = volume p = pressure The equation describes the change in volume that a substance undergoes during a change in pressure while the temperature is held constant. The units are in reciprocal pressure units. When the internal fluid pressure within… Continue reading Isothermal Compressibility
Month: June 2023
Porosity
The porosity of a porous medium is given the symbol of φ and is defined as the ratio of void space, or pore volume, to the total bulk volume of the rock. This ratio is expressed as either a fraction or a percentage. When using a value of porosity in an equation, it is nearly always expressed… Continue reading Porosity
Review of Rock Properties
Properties discussed in this section include porosity, isothermal compressibility, and fluid saturation. Although permeability is a property of a rock matrix, because of its importance in fluid flow calculations, a discussion of permeability is postponed until in which single-phase fluid flow is considered.
Introduction
As fluid from a reservoir is produced and brought to the surface, the fluid remaining in the reservoir experiences changes in the reservoir conditions. The produced fluid also experiences changes as it is brought to the surface. The reservoir fluid typically sees only a decrease in pressure, while the produced fluid will experience decreases in… Continue reading Introduction
Peak Oil
Since oil is a finite resource in any given reservoir, it would make sense that, as soon as oil production from the first well begins in a particular reservoir, the resource of that reservoir is declining. As a reservoir is developed (i.e., more and more wells are brought into production), the total production from the reservoir… Continue reading Peak Oil
Production from Petroleum Reservoirs
Production from petroleum reservoirs is a replacement process. This means that when hydrocarbon is produced from a reservoir, the space that it occupied must be replaced with something. That something could be the swelling of the remaining hydrocarbon due to a drop in reservoir pressure, the encroachment of water from a neighboring aquifer, or the… Continue reading Production from Petroleum Reservoirs
Reservoir Types Defined with Reference to Phase Diagrams
From a technical point of view, the various types of reservoirs can be defined by the location of the initial reservoir temperature and pressure with respect to the two-phase (gas and liquid) envelope as commonly shown on pressure-temperature (PT) phase diagrams. Figure 1.4 is the PT phase diagram for a particular reservoir fluid. The area enclosed by… Continue reading Reservoir Types Defined with Reference to Phase Diagrams
Introduction to Terminology
The purpose of this section is to provide an explanation to the reader of the terminology that will be used throughout the providing context for the terms and explaining the interaction of the terms. Before defining these terms, note Fig. 1.2, which illustrates a cross section of a producing petroleum reservoir. Figure 1.2 Diagram to show the… Continue reading Introduction to Terminology
History of Reservoir Engineering
Crude oil, natural gas, and water are the substances that are of chief concern to petroleum engineers. Although these substances can occur as solids or semisolids such as paraffin, asphaltine, or gas-hydrate, usually at lower temperatures and pressures, in the reservoir and in the wells, they occur mainly as fluids, either in the vapor (gaseous) or in the liquid phase… Continue reading History of Reservoir Engineering
Introduction to Petroleum Reservoirs
Oil and gas accumulations occur in underground traps formed by structural and/or stratigraphic features.1* Figure 1.1 is a schematic representation of a stratigraphic trap. Fortunately, the hydrocarbon accumulations usually occur in the more porous and permeable portion of beds, which are mainly sands, sandstones, limestones, and dolomites; in the intergranular openings; or in pore spaces caused by joints, fractures,… Continue reading Introduction to Petroleum Reservoirs