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Regression in Zoned / Continuous analysis
Rate calculation is treated as an optimization
problem using nonlinear regression, with full flexibility
in the type and number of input measurements, as
long as they are in sufficient number and include
apparent velocity, density, pressure gradient,
capacitance, phase holdup, phase velocity, phase
rate, temperature, etc. Calculations may be zoned
or continuous. The zoned calculation focuses on
user defined intervals. The continuous method
seeks agreement everywhere on the logs, and the
holdups are treated as variables, allowing a possible
deviation from the slip model. The zoned method
works well most of the time and it is very fast. The
continuous method may provide a better answer in
complex cases and when attempting to match the
temperature. The user has the choice.
Local vs. global regression
The local regression in the zoned method calculates
cumulative rates on selected intervals. This may also
be the starting point for the continuous method,
where a global regression solves for the contributions
of the inflow intervals. Such regression solves for the
entire well at once using user-defined constraints
such as the contribution sense, surface rates, etc. It
is also possible to fix any particular contribution to a
fixed or null value.
Interpretation models
Emeraude offers a complete range of flow models
from single to 3-phase. Specific models are provided
to handle flow re-circulation and standing water
columns. Three and two-phase liquid-liquid stratified
models for horizontal and highly deviated wells are
available. It is possible to connect user models
through an external DLL interface.
Zone rates
Continuous analysis results
Flow map
