Reservoir Characterization. Группа авторов
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Название: Reservoir Characterization

Автор: Группа авторов

Издательство: John Wiley & Sons Limited

Жанр: Физика

Серия:

isbn: 9781119556244

isbn:

СКАЧАТЬ The correlation of the values is 0.95. Figure 2.9 also shows the cross plot of the experimental and estimated shear wave velocities along with a best fitted line. The correlation of the values is 0.96.

image Schematic illustration of experimental shear wave velocity against compressional wave velocity.

      Since Greenberg-Castagna model assumptions is ideal for a specially designed environment, there is no great match between this model and laboratory values. But as was mentioned earlier, correspondence between the velocity, the pressure and shear are very close together. It seems environment effective pressure is the essential factor that change is not considered in the model. This effect is highlighted on shear wave velocity and shear wave module.

image Schematic illustration of a plot of Laboratory vs. estimated Bulk modulus (K) of rock sample. image image Schematic illustration of a plot of laboratory vs. estimated shear modulus. image

      In this paper we evaluated the closeness of the estimated elastic wave velocities and elastic modulus of a rock sample via Gassmann - Greenberg - Castagna formula to those obtained from laboratory measurements at reservoir pressure.

       Estimating the physical parameters of rock samples from Gassmann - Greenberg - Castagna equations at high pressures is farther from the real situation. At high pressure, velocity values are more differentiated from each other and the estimated values are observed to be very far from the experimental (laboratory) values. Although it appears that at higher pressures cracks or fractures get closed, in substituting the fluid, especially brine for supercritical carbon dioxide and water, elasticity values have very high variations, and this very strongly influences the estimated compression wave velocities. And finally, this effect can be seen on the shear wave derived from compression wave. But since the shear wave velocity in the fluid and gas behave similarly, the effect СКАЧАТЬ