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The value plotted 1- r o -  b w we get on the horizontal
axis and extending to the intersection with the graph, we get the
desired value z f .
Prof. Borisov showed that increased filtration resistance
in the zone of replacement of oil with water can be considered the
introduction of a formula filtration resistance coefficient for this
zone to increase filtration resistance.
Coefficient to increase filtration resistance α shows in
how many times the increased resistance in the zone of
replacement of oil with water. For strip, the deposit is determined
by the formula

  w  7,1  8z  25z 2 , (3.22)
 oil f f
where z f - oil saturation at the front water-oil displacement.
For circle deposit we have two cases:
1) the displacement of oil by water from the periphery to
the centre
   r   r  
2
  w  7 , 1 8z   f   25z   f  ;

1
 oil  f 1  R 0   f 2  R 0    



2) the displacement of oil by water from the centre to the
periphery
   R   R  
2
 2   w  7,1  z8  `    r 0   25  2 `  r 0  .
z



f
f 1




 
oil  f f
where  1,  2,  1’,  2’ - auxiliary functions that are dependencies
on graphs (Fig. 3.8); R 0 - the radius of the initial position WOC, m;
R f - radius of the intermediate position WOC, m.

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