Schlu

mb

erg

er P

rivateSOLUTION Section

This slide does not appear in the manual

SIS Training

2

Schlu

mb

erg

er P

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

3

Schlu

mb

erg

er P

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

4

Schlu

mb

erg

er P

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

5

Schlu

mb

erg

er P

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

SIS Training

6

Schlu

mb

erg

er P

rivate

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

SIS Training

7

Schlu

mb

erg

er P

rivate

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

8

Schlu

mb

erg

er P

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

SIS Training

9

Schlu

mb

erg

er P

rivate

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

SIS Training

10

Schlu

mb

erg

er P

rivate

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

t

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

SIS Training

11

Schlu

mb

erg

er P

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

12

Schlu

mb

erg

er P

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

SIS Training

13

Schlu

mb

erg

er P

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

i

e

l

d

P

r

o

d

u

c

t

i

o

n

R

a

t

e

History Period

(Initialization Run)

(Restart Run)

Time

Cell

Saturations &

Pressures

recorded

SIS Training

14

Schlu

mb

erg

er P

rivateEnumeration

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

15

Schlu

mb

erg

er P

rivate

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

SIS Training

16

Schlu

mb

erg

er P

rivate

This slide does not appear in the manual

EX 5: Sector Model Initialization