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angle , the direction of well curvature. Value ,  and 
correspond defined depths of measurement.
Directional angle - the angle between the northern end of
the axial meridian (or X axis of the geographical grid of the zone)
and given direction; it’s measured from the north side of the prime
meridian clockwise. The value of directional angle is given by

     D
, (5.1)

where  - convergence angle (the angle between the axial meridian
and the meridian at that point, it can be positive or negative); D -
magnetic deviation (east - with the plus sign, west - with a minus
sign).
Thus, to obtain directional angle of curvature the hole
should be up to the value of the measured magnetic azimuth angle
 add some  ± D, the value of which is usually indicated on maps.
According to the angle measurement of curvature wells and
calculated directional angle is built inklinograma - well-axis
projection on a horizontal plane (Fig 5.4). Well inklinograma are
prepared by consistent constructing horizontal projections of
individual sections of the well, starting with the lowest depth. The
value  and  are determined in some points and conventionally
accepted as a medium for the interval between two adjacent points.
The horizontal projection of the i-th interval with angle
curvature 
 l  l sin 
i i i , (5.2)

where l i = H i - H i-1 - the length of the interval: H i-1 and H i - depth
location of the upper and lower range points.
Defining sequentially by formula horizontal projection of
certain intervals, putting their values to scale in areas of directional
angles and connecting the start point of the first interval with the
end point of the last interval, we get the total horizontal projection

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