A familiar Workflow
The workflow in Amethyste is similar to other Ecrin
modules, with a control panel guiding the engineer
through the default steps. This includes (1) defining
the type of problem (2) defining the PVT, (3) defining
the well, (4) Calculating the VLP, (5) calculating the
IPR, (6) running the sensitivity analysis.
1+2. Defining the problem and PVT
The document initialization dialog is very
straightforward. The user defines the type of well
(producer or injector) and the reference phase. The
user also defines the PVT, which is the same standard
black oil PVT used in other Ecrin modules.
3. Defining the Well
Wellbore and flow line can be treated independently
or together. The wellbore flow may take place in the
tubing or the annulus. Well trajectory, ID, roughness
and detailed completion are also defined. Any
number of restrictions can be included. A well sketch
is available for graphical display using a library of
pre-defined completion elements. A well plot is then
4. Vertical Lift profile (VLP)
Multiple pressure drop models may be defined, though
one has to be selected as reference. Each model
can be assigned factors to honor observed data. A
temperature profile must be loaded or calculated. The
built-in temperature model uses a segmented model
incorporating convection, conduction, and thermal
Amethyste’s VLP option generates traverses (p vs.
depth) and VLP plots (p vs. q). For each scenario,
user data can be input, manually, from a file, or picked
from production data. On validation, each scenario is
run and the corresponding plot built. The plot content
can be customized interactively.
5. Inflow Performance Relationship (IPR)
An IPR study performed with Saphir NL may be
drag-dropped into Amethyste, and the IPR part of the
analysis is immediately complete. Alternatively, test
data can be loaded or drag-dropped into Amethyste.
The IPR option, which is identical to that in Saphir
NL, is used to define a single, or composite layer
IPR. Multiple models can be selected and compared,
though one has to be selected as reference. For those
models using a skin, the user can input a total skin
or calculate the skin components using a completion
model. User data can be added for comparison with
the model(s). An IPR plot is created that can be
4+5. Well Performance Analysis (WPA)
As soon as they both exist, Amethyste overlays the
VLP and the IPR. The intersection point gives the
solution for a given set of surface conditions.
6. Running Sensitivity
Amethyste can perform as many sensitivity studies
as needed. A given study will correspond to a set of
user controlled values for an IPR parameter, a VLP
parameter or both. A cross correlation between the
resulting rates and the sensitivity parameters can then
be displayed. In v4.20 a new sensitivity study shows
the evolution of the productivity index as a function of
the time when the reservoir starts to deplete.
Report, export and plot
Amethyste has an extensive range of reporting,
exporting and printing capabilities. Lift curves can be
generated in Eclipse™ format for third party software.
The browser can be used to drag-drop components
between analyses or between other Ecrin modules.
In particular, a whole VLP object can be dropped in
Saphir NL, Topaze NL or Rubis and run from those
modules with the possibility of changing any model