Author: haroonkhan
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Darcy’s Law and Permeability
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.…
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Introduction
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…
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Maximum Efficient Rate (MER)
Many studies indicate that the recovery from true solution gas-drive reservoirs by primary depletion is essentially independent of both individual well rates and total or reservoir production rates. Keller, Tracy, and Roe showed that this is true even for reservoirs with severe permeability stratification where the strata are separated by impermeable barriers and are hydraulically…
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Volatile Oil Reservoirs
If all gas in reservoirs was methane and all oil was decane and heavier, the PVT properties of the reservoir fluids would be quite simple because the quantities of oil and gas obtained from a mixture of the two would be almost independent of the temperatures, the pressures, and the type of the gas liberation…
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The Calculation of Formation Volume Factor and Solution Gas-Oil Ratio from Differential Vaporization and Separator Tests
The data in Tables 7.3 and 7.4 can be combined to yield values for the oil formation volume factor and the solution gas-oil ratio. The formation volume factor is calculated from Eq. (7.6) or (7.7), depending on whether the pressure is above or below the bubble-point pressure: For p > bubble-point pressure, For p < bubble-point pressure, where REV = Relative volume from the…
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The Effect of Flash and Differential Gas Liberation Techniques and Surface Separator Operating Conditions on Fluid Properties
Fluid property data are extremely important pieces of information used in reservoir engineering calculations. It therefore becomes crucial to be knowledgeable about methods for obtaining these data. It is also important to relate those methods to what is occurring in the reservoir as gas evolves and then separates from the liquid phase. This section contains…
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Material Balance as a Straight Line
The method developed by Havlena-Odeh of applying the general material balance equation was presented.4,5 The Havlena-Odeh method is particularly advantageous for use early in the production life of a reservoir, as it adds constraints that aid in understanding how the reservoir is behaving. This understanding allows for more accurate prediction of production rates, pressure decline, and…
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The Use of Drive Indices in Material Balance Calculations
The concept of drive indices, first introduced to the reservoir engineering literature by Pirson, was developed.2 To illustrate the use of these drive indices, calculations are performed on the Conroe Field, Texas. Figure 7.1 shows the pressure and production history of the Conroe Field, and Fig. 7.2 gives the gas and two-phase oil formation volume factor for the reservoir fluids. Table…
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Material Balance in Saturated Reservoirs
The general Schilthuis material balance equation was developed in and is as follows: Equation (3.7) can be rearranged and solved for N, the initial oil in place: If the expansion term due to the compressibilities of the formation and connate water can be neglected, as they usually are in a saturated reservoir, then Eq. (7.1) becomes Example…
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Good Gravitational Segregation Characteristics
These characteristics include primarily (1) pronounced structure, (2) low oil viscosity, (3) high permeability, and (4) low oil velocities. Water drive and hydraulic control are terms used in designating a mechanism that involves the movement of water into the reservoir as gas and oil are produced. Water influx into a reservoir may be edgewater or bottomwater, the latter…