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NTNU. Auther : Professor Jon Kleppe. Assistant producers: Farrokh Shoaei Khayyam Farzullayev. Characterization of model. This is a demonstration of 1D Buckley-Leverett problem. Oil is being displaced by water in a horizontal, linear system under diffuse flow conditions.
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NTNU Auther : Professor Jon Kleppe Assistant producers: Farrokh Shoaei Khayyam Farzullayev
Characterization of model • This is a demonstration of 1D Buckley-Leverett problem. • Oil is being displaced by water in a horizontal, linear system under diffuse flow conditions. • The pressure is maintained during the displacement process.
Effect of grid numbers • The water can travel through a course gridded model more quickly than a fine gridded model. Consequently the water front becomes smeared causing a prematurely water break through in the coarse gridded model. This effect is called numerical dispersion. • In practice there are other factors contributing to numerical dispersion such as the averaging of relative permeabilities and of saturations. Animation of Oil Saturation for Case 1, Geometry: 10 x 1 x 10
The greater the number of gridblocks the more closely the model approaches continuum in space in which Buckley Leverett shock-front displacement is honored. Animation of Oil Saturation for Case 2, Geometry: 50 x 1 x 25
Capillary pressure effect • When capillary pressure is included in simulation, the fluid front has relatively round shape. Case 3, the capillary pressure is included ,the geometry is 50 x 1 x 25.
Effect of mobility ratio • With the increase of mobility ratio, M, the shock-front decreases. Case 4, oil viscosity is 10 times higher , geometry: 50 x 1 x 25.
1.0 mo = 1.0 cp 0.8 mo = 10.0 cp 0.6 0.4 0.2 0.0 FW 0.0 0.2 0.4 0.6 0.8 1.0 SW • This graph shows that with the increase in viscosity, curve moves to the left . • From the mobility ratio equation, the increase in oil viscosity brings an increases to the mobility ratio, M.
This slide illustrates two runs of simulation with different mobility ratios, M. • In first case when M is less or equal to 1 cp, the displacement is piston-like. mo=1.0 cp and M=2.0 • In case 2, the mobility ratio is much greater than 1 cp, there is some degree of shock-front displacement that is less than piston like. • As oil has high viscosity, the water is relatively more mobile and it moves bypassing the oil. mo=10.0 cp and M=20.0
References • Kleppe J.: Reservoir recovery course, buckley leverett analysis note • Snyder R. W. and Ramey H. J.: ”Application of Buckley-Leverett Displacement Theory to Noncommunicating Layered System”. SPE paper 1645
About this module • Title: BUCKLEY LEVERTT SIMULATION EXAMPLE • Author: • Name: Prof. Jon Kleppe • Address: NTNU S.P. Andersensvei 15A 7491 Trondheim • Website • Email • Size: 300 Kb