Horizontal permeability

Next, in the 2nd run the horizontal permeabilities of all 15 layers were estimated by using the value of 200 md as initial guess. It required 12 iterations to converge to the optimal permeability values. 

As expected, the estimated values were found to be closer to the correct ones compared with the estimated values when the water-oil ratios are only matched. In the 2nd run, the horizontal permeabilities of layers 5 to 10 (6 zones) were estimated using the value of 200 md as initial guess. It was found necessary to use the pseudo-inverse option in this case to ensure convergence of the computations. The initial and converged profiles generated by the model are compared to the observed data in Figures 18.25a and 18.25b. 

FIGURE 3.6 Point-bar geologic model showing the influence of a sequence of rock textures and structures in a reservoir consisting of a single point-bar deposit on horizontal permeability, excluding effects of diagenesis. (Modified after Ebanks, 1987.)... 

Figure 2. Permeability reduction because of the presence of non-communicating shales. When the aspect ratio (Az/Ax) is small, as in the case of vertical permeability, the reduction is pronounced. When it is large, as for horizontal permeability, the reduction is small. Both extremes can be dealt with analytically. (Reproduced from Ref. 2.)...

If it is possible to drill an open hole into a formation, a simple method of approximating the horizontal permeability may be used. The depth of the hole must be large in relation to its diameter for this method to apply. In this method, the rate of rise in the hole is measured at several elevations and the... 

The layered model discussed here is a two-layer model top layer permeability is 5 md, and bottom layer permeabihty is 50 md. The ratio of vertical permeability to horizontal permeability is 0.1, and the total injection volume is 2 PV. The rest of the input data are the same as the homogeneous model. Figures 4.15 and 4.16 show the recovery factors versus Mjoc and for the initial water saturation of 0.5. 

Fig. 4. Helium porosity and horizontal permeability of low-permeability lenses and host rocks.

Hydraulically the background rock mass was represented by 13 layers with horizontal permeability, kn, decreasing with depth from lO m near surface to 3.35 xl0 m at the assumed repository level just below 500-m depth below 750-m depth kn = 10 m. Vertical permeability was assumed to be 10 kn for the top 300 m below this depth the rock was assumed to be isotropic hydraulically. Porosity was assumed to be 0.003 for the background rock mass. For the vertical fracture zones k was assumed to be 10" m from surface to 400-m depth, below which it decreases rapidly downward. The dipping fracture zone was assumed to have k value of 10 m at all depths. 

The minimum horizontal permeability, or vertical permeability, of cylindrical specimens of bituminous mixtures should range from 0.1 x 10" to 4.0 x 10" m/s, assigned to nine categories, ivertical permeability, and ICho.i to iCi,4.o, for horizontal permeability. 

The vertical permeability value, K or the horizontal permeability value, iCj, is calculated by using Darcy s formula and the modified Darcy s formula, respectively, after measuring the resultant flow rate of water Q, or Qj,. 

In a stratified sequence of deposits, the individual beds, no doubt, will have different permeabilities, so that vertical permeability will differ from horizontal permeability. Consequently, in such situations, it may be necessary to determine the average values of the coefficient of permeability normal to, k, and parallel to, ku, the bedding. If the total thickness of the... 

Certain features of the reservoir and fluids were varied in different calculations. Figure 5 shows the way in which pol3mier crossflow depends on the vertical to horizontal permeability ratio, reservoir... 

We have extended the approach of Rapoport (38) to Include non-isotropic rock permeabilities (36). This allows us to investigate the scaling of crossflow effects in relation to the vertical to horizontal permeability ratio. Four similarity groups are derived in this manner, and these are summarised in Table 3 dispersion groups are also presented, where the dispersion in the flow equation has been taken to be a linear function of horizontal velocity for both longitudinal (x or y) and transverse (z) flow and a is the disperslvity. 

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