OLGA 2018.1 Schlumberger

The OLGA simulator enables key flow simulation applications, including

• liquids handling
• sizing separators and slug catchers
• managing solids
• simulating key operational procedures including start-up, shut-down, and pigging
• modeling for contingency planning
• assessing environmental risk in complex deepwater drilling environments.

New options to initialize pipe wall layer temperatures
In OLGA 2018.1, there are two new options for initializing the pipe wall layer temperatures. Earlier, the
temperatures could only be initialized from solving the steady state thermal conductive equation for the wall, using
the inner- and outer fluid temperatures as boundary conditions. Now, it is possible to set the wall layer
temperatures to the ambient temperature, or to initialize by solving the transient thermal conductive equations for
the wall based on a given time interval. When the transient initialization option is used, the initial wall layer
temperatures equal the ambient temperature, and the inner- and outer fluid temperatures are used as boundary
conditions. The new options can be selected via key INITWALLOPTION under the keyword HEATTRANSFER.
(#859209)
New key in compositional mud tracking
A new key, MUDWEIGHT, is added under the INITIALCONDITIONS and SOURCE keywords, and for pressure-,
mass- and internal nodes. This key can be used to define the mud weight of the drilling fluid when using
compositional mud tracking. The new key can be controlled and exposed, with initial conditions as an exception.
(#859210)
Equilibrium fractions used as initial conditions for flowpaths
It is now possible to let OLGA calculate void fraction and water cut when specifying initial conditions. If negative
values are given to the keys VOIDFRACTION and/or WATERCUT, the equilibrium fractions are used. When
compositional tracking is used, equilibrium void fractions will be calculated based on the initial feed mixture if no
value is specified for VOIDFRACTION.
(#862319)
Relative position of reservoir contact in pipe section
The new setting CUSTOM for key LOCATION, in the RESERVOIRCONTACT keyword, allows the user to define
a LOCATIONFACTOR to position the reservoir contact along a pipe section. The existing location option
BOTTOM is equivalent to a LOCATIONFACTOR of 0.0 and the setting MIDDLE equals a value of 0.5. This
improvement allows the location of reservoir contacts to be defined more precisely in terms of vertical depth and
can be particularly useful in models with large pipe sections.
(#1080775)
Compositional mud tracking
Accumulating calculation error in compositional mud tracking
A small numerical round-off error in one single time step could lead to an accumulated calculation error when
using compositional mud tracking. This error could, for instance, cause an internal water phase to drop out of an
oil-based mud. This has now been fixed.
(#786617)
Overwrite reference temperature and pressure for drilling fluids using compositional mud tracking
In compositional mud tracking, the user can now overwrite the reference pressure and temperature used for
volume ratios and mud weight for a drilling fluid. Earlier, these reference values were fixed at 1 atm and 60°F,
respectively.
(#859202)OLGA 2018.1 Release notes Page 5
December 2018
Schlumberger-Private
Controller
Controlling standard conditions keys in keyword RESERVOIRCONTACT through time varying signal
In OLGA 2017, when COMPOSITIONAL=ON or COMPOSITIONAL=BLACKOIL under OPTIONS, the standard
conditions keys in the RESERVOIRCONTACT keyword did not take into account the time varying signal from a
controller. Only the initial controller signal was used. This is now fixed.
(#1029027)
Drilling
Clinging effect for surge and swab scenarios
The effect of the rotation of a drill string on the pressure and temperature of the surrounding fluid is accounted for
in OLGA. Now, also the effect of the drill string translation is accounted for through modification of the wall friction.
The clinging effect depends on the rate of penetration of the drill string, and the inclusion of this effect improves
the predictions of surge and swab pressures.
(#1178350)
Equipment
Modeling of pipe upsets
A model for simulating pipe upsets, typically used to model the effect of tool joints on a drill string, is now available
in OLGA. The model is available through the keyword UPSETS, that can be added to any flowpath connected to a
bit node. A distributed positioning of several upsets can be achieved through one instance of the keyword. The
model computes the pressure change due to a reduced flow area at the position of the upsets. This includes the
effect of flow area contraction and expansion as well as the change in friction. Two geometry factors, used to vary
the impact of different contraction and expansion angles, are available as user input.
(#1178350)

Product: OLGA 2018.1 Schlumberger
Version: 2018.1
Supported Architectures: x64
Language: english
Supported Operating Systems: Windows 7even or newer
Size: 578M