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The calculations are required to complete design of the Tool and to forecast
the performance of services.
It is necessary to make an adjustment in the Tool design for every single well in order
to provide cost-effective stimulation.
Design SWTorpedo Tool:
Quantity of charges and amount of explosive material in each charge, as well as ignition
of charges in timed succession can be calculated by using principles of superiority that is based on
required intensity and irregularity of stress-state to be created. The goal of the torpedo design is
to adjust amount of explosives and its range of ignition to specifics of the formation's rock. Preset
ultra short time delays between successive charges in torpedo create irregular dynamic stresses and
trigger the dilatancy (σ3 /σ1). Created irregular
dynamic stresses must be in the following range
-1 ≤ σ3 /σ1 ≤ 0.1
Figure 1. Wave's
attenuation in the rock mass with different porosity.
Where attenuation:
1 - for granite
 with
 0.75%
2 - for strong limestone
with
1.1%
3 - for tuff
with
28.4%
4 - for shale
with
28.0%
and:
- is maximum principal stress
- is arbitrary distance from the center of the charge to the point
where maximum principal stress was measured
- is mass of the charge
- is index of the symmetry of explosion
and
Taken from the evaluations and correlations:
 =
  -
Then:
Where:
 and
 are empirical factors
- is empirical factor that characterize velocity of the
wave’s attenuation
=
- is Poisson’s ratio
Observed changes in the rock’s characteristics under uniaxial stress appears when stress
is between 3...5% of the rock’s strength
Forecast the performance:
Calculations will allow finding expected minimum of increase in productivity. The information on minimum
in productivity increase will be presented to a client. If forecasted increase is sufficient, client will decide to
permit the service execution.
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