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This slide does not appear in the manual
SIS Training
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rivatePurpose of the SOLUTION Section
The SOLUTION is used to
define the initial state of every
cell in the model
Initial pressure and phase
saturation
Initial solution ratios
Depth dependence of reservoir
fluid properties
Oil and gas re-solution rates
Initial analytical aquifer
conditions
SIS Training
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rivateECLIPSE Initialization Options
Equilibration - initial pressures and saturations are computed
by ECLIPSE using data entered with the EQUIL keyword
Restart - initial solution may be read from a Restart file
created by an earlier run of ECLIPSE
Enumeration- initial solution is specified by the user explicitly
for every grid block
SIS Training
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rivateEQUIL
Sets the contacts and pressures for conventional hydrostatic
equilibrium
EQUIL items are interpreted differently depending on the
phases present
May have more than one equilibration region (see
EQLDIMS)EQUIL-- D P OWC Pcow GOC Pcog RSVD/PBVD RVVD/PDVD N
7000 4000 7150 0 1* 1* 1* 1* 0 /
EQUIL
SIS Training
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rivateBlock Center Equilibration, Part 1
Pressure
Depth
(Pcow = 0)
OWC = FWL
GOC
EQUIL--D P OWC Pcow GOC Pcog
3500 4000 7150 0 3500 0 /
Datum
+=2
1
12 )()(h
hgdhhPhP ooo
1. Given: Contacts, Datum
and Pressure
2. Using BO EOS, calculate
phase pressures
throughout the model, for
example:TZ
TZ
2
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Datum
Block Centered Equilibrium, Part 2
GOC
TZ
G-O Rel Perm
SGUSGL
KrgKrog
O-W Rel Perm
SWU
SWL
Krw
Kro
GAS ZONE:
Sg = SGU
Sw = SWL
So = 1 SWL - SGU
OIL ZONE:
Sg = SGL, usually zero
Sw = SWL
So = 1 SWL SGL
WATER ZONE:
Sg = SGL, usually zero
Sw = SWU
So = 1 SWU SGL
Sg = 0.77
Sw = 0.23
So = 0.77
Sw = 0.23
Sw = 1.00
1
(Pcow = 0)
OWC = FWL
TZ
Depth
Pressure
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Datum
Block Centered Equilibrium, Part 3
Pressure
Depth
GOC
Pcow
Swi = 0.25
So = 0.75Sw
(Pcow = 0)
OWC = FWL
1. Calculate Pcog and Pcow in the
transition zones of the modelSg = 0.77
Sw = 0.23
So = 0.77
Sw = 0.23
Sw = 1.00
wocow PPP =ogcog PPP =
2. Reverse-lookup Sw from Pc
tables in PROPS section &
assign to cell centers
TZ
TZ
2
SIS Training
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rivateEQUIL Item 9
OWCTZ
Effective OWC
Block Center Equilibrium
N = 0: fluid saturations at the
center of each cell
Steady State
Potential errors in FIP errors
Not Steady-State
(use EQLOPTS QUIESC)
Better FIP estimate
TZOWC
Tilted or level block
integration OWC
i = 1
i = 2
i = 3
i = 2Ni = 2N-1
Level Block Equilibrium
N < 0: average of the conditions at (2 *-N)
horizontal levels within each grid cell
Tilted Block Equilibrium
N > 0: average of the conditions at N levels within
each cell half, weighted according to the cells
horizontal cross-section at each level
1
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Oil saturation from fine scale
equilibration:
So = (A+B)/V
Immobile oil saturation (from saturation
tables)
SOWCR = (B+C)/V
Resulting mobile oil saturation
Somob = (A-C)/V
Correct mobile oil saturation is
Somob = A/V
OWC
SWL SOWCR
A B
D CD
e
p
t
h
Transition Zone
Water Zone
Water Saturation
Mobile fluid correction activated by
EQLOPTSMOBILE /
Mobile Fluid Correction
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TZONEF T F /
ENPTVD3000 1* 0.50 6*3250 1* 0.50 6*3251 1* 0.70 6*3500 1* 0.70 6* /
Water Saturation
D
e
p
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h
Mobile Water in the Transition Zone
Often need to immobilize water below
certain threshold saturation
1) Add TZONE to PROPS section
2) Enter threshold saturation (Swcr*) with
SWCR
3) Swcr* may be varied in history match as
required
TZONEF T F /
EQUALSSWCR 0.70 /
/
Immobile
Water
Mobile
Water
Swcr*=0.70
Immobile
Water
Mobile
Water
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rivateMatching Initial Water Saturation
Often given initial water saturation distribution BUT need EQUIL for
pressure, other phase saturations, etc
1) Input saturation tables as usual, with non-zero Pcow
2) Enter initial water saturation array using SWATINIT in PROPS section
3) Enter EQUIL keyword as usual
ECLIPSE scales Pcow to match initial water saturation given in
SWATINIT
Check scaled Pcow is physically reasonable (INIT file)
PPCWMAX will limit maximum capillary pressure scaling
SIS Training
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rivateInitial Solution Ratios
Used for fluid density calculation
Required as part of the equation of state for the oil and gas
phases
Dissolved gas concentration, Rs or RSVD
Vaporized oil concentration, Rv or RVVD
Bubble point and / or dew point depth variation, PBVD and/or
PDVD
This information
may be supplied
in your PROPS
keywords
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rivateRestart Runs
The solution at the end of the
initialization is set as start
conditions for the history match
Why bother to recalculate initial
saturations & pressures?
Restarts save simulation time!
F
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P
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R
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History Period
(Initialization Run)
(Restart Run)
Time
Cell
Saturations &
Pressures
recorded
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Initial conditions may be set explicitly
This may be appropriate in reservoirs with initially tilted
contacts or non-equilibrium situations
ECLIPSE will check supplied information against phases in
the Runspec section
SIS Training
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RPTSOL
SOIL EQUIL RESTART=2 /
Tabular and printed data to the PRT file
Lots of other properties can be written
Initial conditions to the restart file
Can write out interblock flows & FIP
Can be viewed in 3D ( Petrel, FloViz, FloGrid)
Output Controls
RPTSOL
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This slide does not appear in the manual
EX 5: Sector Model Initialization
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