After the fluid reaches the top, it is likely to be directed toward a manifold connecting a number of wells. The reservoir fluid consists of oil, gas (even if the flowing bottom-hole pressure is larger than the bubble-point pressure, gas is likely to come out of the solution along the well), and water. Traditionally, the… Continue reading The Surface Equipment

The zone surrounding a well is important. First, even without any man-made disturbance, converging, radial flow results in a considerable pressure drop around the wellbore and, as will be demonstrated the pressure drop away from the well varies logarithmically with the distance. This means that the pressure drop in the first foot away from the… Continue reading The Zone near the Well, the Sandface, and the Well Completion

The presence of a substantial porosity usually (but not always) implies that pores will be interconnected. Therefore the porous medium is also “permeable.” The property that describes the ability of fluids to flow in the porous medium is permeability. In certain lithologies (e.g., sandstones), a larger porosity is associated with a larger permeability. In other… Continue reading Permeability

Favorable conclusions on the porosity, reservoir height, fluid saturations, and pressure (and implied phase distribution) of a petroleum reservoir, based on single well measurements, are insufficient for both the decision to develop the reservoir and for the establishment of an appropriate exploitation scheme. Advances in 3-D and wellbore seismic techniques, in combination with well testing,… Continue reading Areal Extent

All hydrocarbon mixtures can be described by a phase diagram such as the one shown in Figure 1-3. Plotted are temperature (x axis) and pressure (y axis). A specific point is the critical point, where the properties of liquid and gas converge. For each temperature less than the critical-point temperature (to the left of Tc in Figure 1-3) there exists a pressure… Continue reading Classification of Reservoirs

Oil and/or gas are never alone in “saturating” the available pore space. Water is always present. Certain rocks are “oil-wet,” implying that oil molecules cling to the rock surface. More frequently, rocks are “water-wet.” Electrostatic forces and surface tension act to create these wettabilities, which may change, usually with detrimental consequences, as a result of… Continue reading Fluid Saturations

Often known as “reservoir thickness” or “pay thickness,” the reservoir height describes the thickness of a porous medium in hydraulic communication contained between two layers. These layers are usually considered impermeable. At times the thickness of the hydrocarbon-bearing formation is distinguished from an underlaying water-bearing formation, or aquifer. Often the term “gross height” is employed… Continue reading Reservoir Height

All of petroleum engineering deals with the exploitation of fluids residing within porous media. Porosity, simply defined as the ratio of the pore volume, Vp, to the bulk volume, Vb, is an indicator of the amount of fluid in place. Porosity values vary from over 0.3 to less than 0.1. The porosity of the reservoir can be… Continue reading Porosity

Volume and Phase of Reservoir Hydrocarbons Reservoir The reservoir consists of one or several interconnected geological flow units. While the shape of a well and converging flow have created in the past the notion of radial flow configuration, modern techniques such as 3-D seismic and new logging and well testing measurements allow for a more… Continue reading Components of the Petroleum Production System

Petroleum production involves two distinct but intimately connected general systems: the reservoir, which is a porous medium with unique storage and flow characteristics; and the artificial structures, which include the well, bottomhole, and wellhead assemblies, as well as the surface gathering, separation, and storage facilities. Production engineering is that part of petroleum engineering that attempts… Continue reading Introduction