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Ecrin v4.12 - Doc v4.12.02 - © KAPPA 1988-2009
Topaze Guided Session #4
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TopGS04 - 7/16
The constraints entered here can correspond to the operational field production limitations due
to logistics and storage, for instance. The following can be specified and modified at any point
in time: oil rate, gas rate, water production, water injection, total liquid rate.
In any Topaze forecast, the governing phase production, Oil or Gas, is driving all the other
phase productions or injections. For this reason, any of the above constraint can be translated
into a constraint on the main phase. This is called the minimum constraint and it is the value
used internally to check the main phase production. Note that at a given time step, this
minimum constraint is a function of Np/N. The minimum constraint can be plotted on the Field
production plot (Well schedule tab). With time, varying colors indicate what constraint is
causing the bottleneck.
Constraints can be handled in 3 ways:
Undefined:
When a constraint value is zero, Topaze will ignore it. This constraint will have no
effect on the calculations or the results.
Flag only:
In this case the constraints have no impact on the production. In the Tables and
Results sections, those values that violate a constraint are highlighted in red. Note for instance
that in an oil case, if the gas production exceeds the gas constraint, then necessarily the oil
production exceeds the ‘minimum constraint’. So violating a constraint other than the one on
the main phase entails the violation of that main phase ‘minimum constraint’ too. Note that
violated means bigger or equal.
Active:
At each time step Topaze calculates the minimum constraint and defers any excess
production to future time steps. In the results/tables Topaze will still highlight what constraints
have been violated or reached, to indicate the bottlenecks. Also, in the Results dialog, Topaze-
Profile will report any deferred production that could not be re-allocated.
We will not impose any constraint here; click on ‘Next’ to move to the next stage of the project
definition – the well profiles.
B01.7 • Well Profiles
The Well Profile facility allows the user to enter new Well Production Profiles or to modify
existing ones. Some defaults profiles (named Producer#1, Gas Injector, Water Injector) are
pre-defined. New well profiles can be defined to be used either for prospective wells (manually
added by the user) or for automatic wells (added by the simulation). Their characteristics -
initial rate, number of declines, decline coefficient - can be modified in this dialog by the user.
In this session we will define two well profiles, with a unique decline in each case. Let us start
with the modification of the default profile ‘Producer 1’, by entering an initial rate equal to
5000 STB/D, a final rate of 250 STB/D, a delay of 0.5 year (this is the time before the decline
steps in), and set the decline to be harmonic with a factor of 0.5. Press ‘Apply’ to visualize the
following curve: