Vertical permeability

Bioturbation, due to the burrowing action of organisms, may connect sand layers otherwise separated by clay laminae, thus enhancing vertical permeability. On the other hand, bioturbation may homogenise a layered reservoir resulting in an unproducible sandy shale. 

In the case of the very low vertical permeability, the horizontal well actually produces at a lower rate than the vertical well. Each of these examples assumes that the reservoir is a block, with uniform properties. The ultimate recovery from the horizontal well in the above examples Is unlikely to be different to that of the vertical well, and the major benefit is in the accelerated production achieved by the horizontal well. 

Because gravity is too weak to be used for removal of cakes in a gravity side filter (2), continuously operated gravity side filters are not practicable but an intermittent flow system is feasible in this arrangement the cake is first formed in a conventional way and the feed is then stopped to allow gravity removal of the cake. A system of pressure filtration of particles from 2.5 to 5 p.m in size, in neutralized acid mine drainage water, has been described (21). The filtration was in vertical permeable hoses, and a pressure shock associated with relaxing the hose pressure was used to aid the cake removal. 

The initial moisture content is a determinant factor in the rate of heat transfer to the center of the core mat [226,227]. At short press closing times the rapid temperature rise occurs at the same time for both lower and higher moisture content percentages indicating that the steam condensation front reaches the core at the same rate and that this is then determined more by local permeability rather than local moisture content. The slope of the rise is similar as it is the balance of horizontal and vertical permeability which controls the rate of steam flow to the core layer. Furthermore, water remains in the surface layer in a quantity such as... 

Weeks, E.P., "Field determination of vertical permeability to air in the unsaturated zone", U.S. Geol. Survey Prof. Paper 1051, 41, 1978. 

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.)...

Ky is the vertical permeability, Ap the fluid density difference (H2O-CO2), g the acceleration of gravity, kf the relative mobility of the least mobile phase (water), A the cross sectional area, Q the injection rate, L the length, and H the height. 

The process of salt dissolution produces cavities, normally at the updip limit or at the top of the salt unit, into which overlying rocks can settle or collapse chaotically. Disrupted rock helps to make salt dissolution a somewhat self-perpetuating process, inasmuch as cavern development followed by collapse and fracturing of the rock will cause a greater vertical permeability, and this allows further access of fresh water to the salt. 

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. 

In Case C, the horizontal and vertical permeability is set vice versa. This is concerning to the uncertainty about the fracture direction. If the fracture direction is measured incorrectly, the anisotropy of the permeability may be differently evaluated. In this study, while the degree of anisotropy is not so large, the effect of the small difference of the interpretation on the anisotropy is exaB)in lse D, the relation of the thermal disturbance and value of permeability is discussed. While the heat generation at the repository is assumed by the realistic estimation, the thermal disturbance around the repository is very dependent on the permeability of rock mass. When the permeability is low, the buoyancy effect by heat generation can be emphasized because the boundary condition does not have a large effect on the entire ground-water movement. 

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 drainage capacity is determined by the requirement for void content or minimum permeability (horizontal or vertical permeability). 

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, i[Pg.260]

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... 

FIG 5 DEPENDENCE OF POLYMER CROSSFLOW ON VERTICAL PERMEABILITY OF 2-LAYER RESERVOIR... 

CROSSFLOW OF OIL IN 2-LAYER RESERVOIRS OF DIFFERENT VERTICAL PERMEABILITY... 

Placement of a gel-forming composition into a high permeability streak of a reservoir is most successful in diverting the flow when a low level of crossflow exists between various layers of the reservoir. At least one modeling study of a reservoir with relatively high vertical permeability has shown a significant incremental oil recovery. The amount of incremental oil is sensitive to the level of permeability reduction. However, once the treated zone ends up with a permeability as low or lower than the adjacent reservoir layer, further reduction makes little difference. 

Bankvall, C.G., Natural Convection in Vertical Permeable Space. Warme- und Stoffiibertragung, 1974. 7 p. 22-30. 

Sample compressibility compressibility vertical permeability horizontal permeability ... 

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