51139450-ECL-intro

ARCS2: Advanced Reservoir Characterization & Simulation

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Reservoir Simulation

Introduction to ECLIPSE

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Reservoir Simulation November 27th,

2008

Introduction to ECLIPSE Content

General informations Section header keywords Keywords in sections Datafile structure Running simulation Visualization of results Exercise

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General Informations

ECLIPSE 100 is a fully-implicit, three phase, three dimensional, general purpose black oilblack oil simulator with gas condensate option.

ECLIPSE 100 can be used to simulate 1, 2 or 3 phase systems. Two phase options are solved as two component systems. In addition to gas dissolving in oil (variable bubble point pressure or gas/oil ratio), ECLIPSE 100 may also be used to model oil vaporizing in gas (variable dew point pressure or oil/gas ratio).

Both corner-point and conventional block-center geometry options are available in ECLIPSE. Radial and Cartesian block-center options are available in 1, 2 or 3 dimensions.

What is ECLIPSE 100?

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General InformationsHow to start?

To run simulation you need an input file with all data concerning reservoir and process of its exploitation.

Input data for ECLIPSE is prepared in free format using a keyword system. Any standard editor may be used to prepare the input file. Alternatively ECLIPSE Office may be used to prepare data interactively through panels, and submit runs.

The name of input file has to be in the following format: FILENAME.DATA

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General Informations

An ECLIPSE data input file is split into sections, each of which is introduced by a section-header keyword. A list of all section-header keywords is given in following, together with a brief description of the contents of each section and examples of keywords using in file code.

The keywords in the input data file (including section-header keywords) are each of up to 8 characters in length and must start in column 1. All characters up to column 8 are significant. Any characters on the same line as a keyword from column 9 onwards will be treated as a comment.

Note that all keywords in input file have to be in proper order.

Input data file

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Section-header keywordsList of section-header keywords in proper order:

The sections must be specified in the shown order.

It is recommended that the body of sections which are not frequently changed be held in separate files which are included in the data using the INCLUDE keyword.

A data record has to be ended with a slash [/]

RUNSPEC

GRID

PROPS

REGIONS

SOLUTION

SUMMARY

SCHEDULE

EDIT

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Section-header keywords

Status: REQUIRED

Title, problem dimensions, switches, phases present, components etc.

GRID Status: REQUIRED

RUNSPEC

The GRID section determines the basic geometry of the simulation grid and various rock properties (porosity, absolute permeability, net-to-gross ratios) in each grid cell.

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Status: OPTIONAL

Modifications to calculated pore volumes, grid block centre depths and transmissibilities.

PROPS Status: REQUIRED

EDIT

Tables of properties of reservoir rock and fluids as functions of fluid pressures, saturations and compositions (density, viscosity, relative permeability, capillary pressure etc.). Contains the equation of state description in compositional runs.

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Status: OPTIONAL

Splits computational grid into regions for calculation of: PVT properties (fluid densities and viscosities): PVTNUM

saturation properties (relative permeabilities and capillary pressures): SATNUM

initial conditions, (equilibrium pressures and saturations): EQLNUM

fluids in place (fluid in place and inter-region flows): FIPNUM

If this section is omitted, all grid blocks are put in region 1.

SOLUTION Status: REQUIRED

REGIONS

Specification of initial conditions in reservoir may be: calculated using specified fluid contact depths to give potential equilibrium

read from a restart file set up by an earlier run

specified by the user for every grid block (not recommended for general use)

This section contains sufficient data to define the initial state (pressure, saturations, compositions) of every grid block in the reservoir.

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Status: REQUIRED

Specification of data to be written to the Summary file after each time step. Necessary if certain types of graphical output (for example water-cut as a function of time) are to be generated after the run has finished. If this section is omitted no Summary files are created.

SCHEDULE Status: REQUIRED

SUMMARY

Specifies the operations to be simulated (production and injection controls and constraints) and the times at which output reports are required. Vertical flow performance curves and simulator tuning parameters may also be specified in the SCHEDULE section.

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data checking only, with no simulation

Keywords in sections

TITLE title

DIMENS

OIL, WATER, GAS, VAPOIL, DISGASFIELD/METRIC/

LABWELLDIM

S

UNIFIN

UNIFOUT

START

NOSIM

number of blocks in X,Y,Z directions

the active phases present

unit convention

well and group dimensions

indicates that input files are unified

indicates that output files are unified

start date of the simulation

RUNSPEC sectionRUNSPEC section

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TOPSdepths of top faces of grid blocks for the current box; data is taken from Structure map, and geological model from PETREL

DX, DY, DZ

PERMX, PERMY, PERMZ

PORO

X,Y,Z-direction grid block sizes for the current box; data is taken from Isopac map, and geological model from PETREL

X,Y,Z-direction permeabilities for the current box; data is taken from Isopac map, and geological model from PETREL

grid block porosities for the current box; data is taken from Isopac map, and geological model from PETREL

GRID sectionGRID section

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reservoir fluidreservoir fluidproperties fromproperties from

PVT analysisPVT analysis

saturation tablessaturation tablesfrom specialfrom specialcore analysiscore analysis

Keywords in sectionsPROPS sectionPROPS section

SWFN

SOF3

SGFN

PVTO

DENSITY

water relative permeability and capillary pressure as functions of Sw

oil relative permeability as a function of So

in three phase system

gas relative permeability and capillarypressure as functions of Sg

FVF and viscosity of live oil as functions of pressure and Rs

stock tank fluid densities

PVTG

PVTW

FVF and viscosity of wet gas as functions of pressure and Rv

FVF, compressibility and viscosity of water

ROCK rock compressibility

NEXTREMOV

E

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REGIONS sectionREGIONS section


FIPNUM fluid-in-place regions

SATNUM

EQLNUM

PVTNUM

saturation table regions

equilibration regions

PVT data regions

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SOLUTION sectionSOLUTION section


EQUIL fluid contact depths and other equilibration parameters; data taken from well testing

RESTART

RPTSOL

name of the restart file

report switches for SOLUTION data

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AquifersNumerical:WOC discretization

WOC

WOC

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Modelling Aquifers

Gridding Numerical Aquifers

Closed Analytical Aquifers

Fetkovich Carter Tracy

Types of aquifer models

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AquifersEclipse keywords: Numerical

RUNSPEC

In order to use the facility, the maximum number of numerical aquifer blocks and the maximum number of lines of connection data in AQUCON should be set using the RUNSPEC section keyword AQUDIMS.

GRID

AQUCON connects a numerical aquifer (declared using the AQUNUM keyword) to one or more reservoir cells. The connection to the reservoir is set up by an arbitrary box defined by lower and upper I, J and K indices.

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AquifersEclipse keywordsNumerical

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AquifersEclipse keywordsFetkovich

RUNSPEC

In order to use the facility, the maximum number of analytic aquifers and the maximum number of grid block connected to any single analytic aquifer should be set using the RUNSPEC section keyword AQUDIMS.

SOLUTION

The aquifer properties (C, , Pi, depth, PI, etc.) should be defined using keyword AQUFETP, and the aquifer connections to one or more faces of the reservoir should be made through the keyword AQUANCON.

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AquifersEclipse keywords: Fetkovich

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AquifersEclipse keywords: Carter Tracy

RUNSPEC

In order to use the facility, the maximum number of analytic aquifers and the maximum number of grid block connected to any single analytic aquifer should be set using the RUNSPEC section keyword AQUDIMS.

PROPS

The aquifer should also be given a table number for the influence function table that it should use. Influence function tables may be supplied with the AQUTAB keyword in the PROPS section. Eclipse has a built-in default influence function table (# 1), which represents the constant terminal rate solution for an infinite aquifer as given by van Everdingen and Hurst.

SOLUTION

The aquifer properties (C, , Pi, depth, R, etc.) should be defined using keyword AQUCT, and the aquifer connections to one or more faces of the reservoir should be made using the keyword AQUANCON.

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AquifersEclipse keywordsCarter Tracy

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Fxxx Field quantities

Gxxx

Rxxx

Wxxx

Cxxx

Bxxx

Group quantities

Region quantities

Well quantities

Connection quantities

Block quantities

SUMMARY sectionSUMMARY section

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FOPT Field or Well Oil Production Total

FOPR

FGOR

FWCT

FOE

FPR

FORFR

Field or Well Oil Production Rate

Field or Well Gas-Oil Ratio

Field or Well Water Cut

Field Oil Efficiency

Field PressureField Fraction Total Oil Produced by Rock Compaction


WOPT

WOPR

WGOR

WWCT

FOIP

FORFE

FORFF

Field Oil in Place

FWIR WWIR Field or Well Water Injection Rate

FWIT WWIT Field or Well Water Injection Total

FORFWField Fraction Total Oil Produced by Water or Gas InfluxFORFGField Fraction Total Oil Produced by Oil Expansion or Gas ExpansionFORFS

Field Fraction Total Oil Produced by Free Gas Influx

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Time of CPU Usage


WBHPWell Bottom Hole Pressure or Tubing Head Pressure

WBP5

WPI5

WOPRH

TCPU

Well 5 or 9-Point Pressure AverageWell Productivity Index Based on Value of WBP5 or WBP9Well Oil Production Rate or Oil Production Total History

Well Mode Control


WMCTL

WTHP

WBP9

WPI9

WWCTH Well Water Cut or GOR HistoryWGORH

WOPTH

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Keywords in sectionsSCHEDULE sectionSCHEDULE section

RPTSCHED

TUNING

WELSPECS

COMPDAT

WCONHIST

report switches to select which simulation results are to be printed at report times

time step and convergence controlsintroduces a new well, defining its name, the position of the wellhead, its bottom hole reference depth and other specification data

specifies the position and properties of one or more well completions; this must be entered after the WELSPECS

observed rates for history matching wells

WCONPROD

WCONINJE

control data for production wells

control data for injection wells

TSTEP or DATE

advances simulator to new report time(s) or specified report date(s)

NEXT

REMOVE

ARCS2: Advanced Reservoir Characterization & Simulation

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Data review

Reservoir Simulation Modeling

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In history Matching, observed average rates are known; controls are simple.

VFP tables are introduced at the end of history matching process to ensure the continuity between matching runs (set measured Q) and prediction runs (limit THP).

Well controls: history matchMain Controls

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Imposed Flow rate Oil, Water, Gas, Liquid, Reservoir voidage

Imposed pressure Tubing Head Flowing pressure Bottom Hole flowing pressure

Well controls: forecastingMain Controls

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Flow rates Economic limits Rates upper limit per phase Maximum ratios (Wcut, GOR, WGR)

Pressures BHP and THP limit (lower for a producer, upper for an

injector) Maximum drawdown

Well controls: forecastingSecondary Controls

VFP tables are used to relate bottom hole to well head pressuresVFP tables are used to relate bottom hole to well head pressures

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Well Constraints

Technical (well and/or surface facilities) Economical For the simulator:

Pressure Target: Maximum or imposed WHP/BHP minimum for producer – maximum for injector maximum for some layers

Rate Target: surface: Qo, Qg, QL

bottom: Qt (history match)

Secondary constraints: WCT, GOR, P limits Monitoring: actions when a constraint is offended

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Group of well Constraints

Hierarchy: Wells, Groups, Platforms, FieldWells, Groups, Platforms, Field Constraints:

On rates for main phase (economical, contracts, capacity) On rates for secondary phase (capacity of flaring, water treatment)

and gas lift rate X-dependency: Qproduction = f(Qinjection), Pressure maintenance

Monitoring: Opening of waiting wells Shut-in of most water flooded well

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Eclipse keywordsWell definition & controls: SCHEDULE Section

SCHEDULE

--restart resultsRPTRST

--well specification and completionWELSPECSCOMPDAT

--production constraintsWCONPROD

--timestep management and tolerance criteriaTUNING

DATES1 'AUG' 2008 //END

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Eclipse keywordsWell definitions

WELSPECS-- 1 2 3 4 5 6 --name group i j BHP_ref_dep phase ‘P1’ 'PROD' 20 7 2500 'OIL' //

Well P1 belongs to group PROD Well head is at i=20, j=7 BHP reference depth of 2500. Defaults to depth of top-most

connection OIL is the preferred phase (used only for PI output) Other items can usually be defaulted

WELSPECS: General specification data for wells

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Eclipse keywordsWell completions

COMPDAT-- 1 2 3 4 5 6 7,8 9 10 11 --name i j k1 k2 status diameter skin ‘P1’ 20 7 3 8 'OPEN' 2* 0.15 1* 2 //

Well P1 is completed in layers 3 to 8 of colum i=20, j=7 The well bore diameter is 0.15 m and the skin is +2 Eclipse will compute the connection factor using the Peaceman

formula: for a vertical well using kh values of the completed cells

COMPDAT: Well completion specification data

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Eclipse keywordsWell completions

COMPDAT-- 1 2 3 4 5 6 7 8 9 10 11 12 13--name i j k1 k2 status CF diam kh skin direction ‘P1’ 20 7 3 3 'OPEN' 1* 23.47 0.15 / ‘P1’ 20 7 4 4 'OPEN' 1* 6.14 0.15 / ‘P1’ 20 6 4 4 'OPEN' 1* 8.25 0.15 / ‘P1’ 20 6 5 5 'OPEN' 1* 94.70 0.15 520.3 2 1* Z //

P1 is a deviated well crossing columns (20,7) and (20,6) completed in layers 3 to 5

The CF have been calculated in SCHEDULE application and input in item 8

the well bore diameter must be given kh, skin and direction of penetration may be given for information as in

the last line above

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Eclipse keywordsProduction Well Controls

WCONPROD-- 1 2 3 4 5 6 7 8 9 10 11 --name status control Qos Qws Qgs Qls Qfond BHPlim THPlim VFP ‘P1’ 'OPEN' 'ORAT' 500 300 1000 1* 1* 50 15 1 //

Well P1 has a target oil rate of 500, subject to: Maximum water rate of 300. Maximum gas rate of 1000. Minimum BHP of 50. Minimum THP of 15

VFP table 1 applies to this well.

WCONPROD : Control data for production wells

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WECON : Economic limit data for production wells

Eclipse keywordsWell Economic Constraints

WECON-- 1 2 3 4 5 6 7--name Qomin Qgmin maxWCT maxGOR maxWGR action ‘P1’ 50 1* 0.8 1* 1* ‘CON’ //

Well P1 is subject to: A minimum oil rate of 50 sbpd: connections of P1 will be closed if this

rate cannot be met. A maximum water cut of 0.8: the connections with the highest WCT will

be closed

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Eclipse keywordsInjection Constraints

Injectors are controlled by: Target rate: surface or reservoir rate of the injected fluid.

(target rate subject to minimum BHP) Fixed pressure: BHP or THP

(target BHP subject to maximum rate)

ECLIPSE will always honour the most constraining limitECLIPSE will always honour the most constraining limit

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Eclipse keywordsInjection Well Controls

WCONINJE-- 1 2 3 4 5 6 7 8 9--name phase status control Qs Qres BHPlim THPlim VFP ‘I1’ 'WATER' 'OPEN' THP 1000 1* 300 40 2 //

Well I1 injects water at THP = 400 bar, subject to: Maximum rate of 1000 sm3/d. Maximum BHP of 300 bar.

VFP table 2 applies to this well.

WCONINJE : Control data for injection wells

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WELOPEN: Opens and closes both wells and completions.

Eclipse keywordsOther well controls

WELOPEN--name action ‘P1’ 'OPEN' / opens P1, does not alter completions 'P2' 'STOP' / closes P2 but allows cross-flow ‘P3’ 'OPEN' 0 0 0 / opens all completions in P3 ‘P4’ 'SHUT' 0 0 2 / closes all completions in P4 in layer 2 ‘P5’ 'SHUT' 0 0 0 4 6 / closes completion 4, 5 and 6 of P5/

Opening a well and its completions requires 2 lines. Possible well status: OPEN, SHUT, STOP or AUTO Possible completion status: OPEN, SHUT or AUTO

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WEFAC: Defines well activity or efficiency factor (downtime).

Eclipse keywordsOther well controls

WEFAC-- 1 2 --name efficiency ‘P1’ 0.95 //

The well P1 is 95% of the time on production, for example to model shut-down of 1 day each month.

Well rates and pressures are calculated using full rate, group rates and all cumulatives account for the efficiency factor.

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Eclipse keywordsConcluding remarks Output complete information about well connections to the

PRT file:RPTSCHEDWELSPECS /

The basic Eclipse well model is: Usually acceptable for vertical and deviated wells. Acceptable for horizontal wells if frictional losses in the drain are

negligible: use the well-bore friction option. Not usually acceptable for complex, multi-branch wells: use the

Multi-segmented Well (MSW) option. Always try to calibrate simulated well productivity against

measured or calculated values ATENTIONATENTION: Setting a large CF to avoid problems often leads to

convergence problems

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TUNING: Sets simulator control parameters.Record 1: Time stepping controlsRecord 2: Time truncation and convergence controlsRecord 3: Control of Newton and linear iterations

Eclipse keywords

TUNING 1 50 0.1 / Timestep = 1 day, upper limit of next timestep = 50 days, and

minimum length of all timesteps

/1* 1* 25 / Minimun & maximum number of Newton iteration defaulted,

and maximum number of linear iteration = 25

Timestep management and convergence

NEXTSTEP: Sets a maximum length of the next time step (useful when opening a well)

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Datafile structure

In the data following a keyword, asterisks may be used to signify repeat counts. A data quantity can be repeated a required number of times by preceding it with the required number and an asterisk.

There must be no intervening blank spaces next to the asterisk on either side. For example, the two following cases are equivalent:

Repeat counts

RPTSCHED 0 0 0 0 0 0 0 0 0 0 0 2 0 0 2 /

RPTSCHED 11*0 2 2*0 2 /

Any lines beginning with the two characters ‘--’ are treated as comments, and will be ignored by ECLIPSE. Comment lines (and blank lines also) may be inserted anywhere in the data file. Comments may also be added to the end of lines of data by beginning the comment with the two characters ‘--’, but in this case the comments must not contain any quotes.

Comments

-- VARIATION OF INITIAL RS WITH DEPTH---- DEPTH RSRSVD 8200 1.270 8500 1.270 /

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Datafile structure

Certain items of data can be defaulted to a built-in default value. The keyword description will indicate when defaults can be applied. There are two ways of setting quantities to their default values:

1. by ending a data record prematurely with a slash (/) the quantities remaining unspecified will be set to their default values.

2. selected quantities positioned before the slash can be defaulted by entering n* where n is the number of consecutive quantities to be defaulted. For example, 4* will cause the next FOUR quantities in the keyword data to be given their default values. There must be no blank space between the number and the asterisk. If there is only one item at a time to be defaulted, then 1* must be entered (an asterisk by itself is not sufficient).

Default values

WCONPROD 'PRODUCER' 'OPEN' 'ORAT' 20000 4* 1000 //

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Running simulationThere are two ways to launch simulation:

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Running simulation The simulation will start. While the model is running, status

reports will be written to the file FILENAME.PRT. If input file was not prepared properly the simulation would stop and then you can check for errors on FILENAME.PRT file and try to correct them.

When the run is finished, your folder contains the following files:

FILENAME.DBG FILENAME.EGRID FILENAME.PRT FILENAME.INIT FILENAME.SMSPEC FILENAME.UNRST FILENAME.UNSMRY FILENAME.RSSPEC FILENAME.INSPEC

Next step is visualization of obtained results

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Visualization of results

FILENAME.PRT Script file with errors report

FILENAME.SMSPEC

FILENAME.EGRID

FILENAME.INIT

Field, well, block performances in OFFICE application

3D view in FLOVIZ application

Output filesOutput files

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Visualization of resultsOFFICE

Field, well, block performances in OFFICE application

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Visualization of resultsFLOVIZ 3D view in FLOVIZ application

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ECLIPSE exerciseObjectives

Simulate the behavior of a development well Optimize its location Data review Flow simulations

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ECLIPSE exerciseItems to be investigated

Production mecanisms: natural depletion, gas cap drive, water influx and water injection

Well's location: 9 possible locations for producer and 2 possible locations for injector

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Rhombo exercise

Top of the reservoir

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Rhombo exercisex-z cross section geometry

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Rhombo exercisePossible wells location

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Rhombo exerciseReservoir layering

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Rhombo exerciseOil PVT functions

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Rhombo exerciseGas PVT functions

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Rhombo exerciseWater – oil Special Core Analysis

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Rhombo exerciseGas – oil Special Core Analysis

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Rhombo exerciseTasks

Look at the ECLIPSE data file Simulate different scenarii and visualize results: 2D,

3D Compare at each case: oil recovery, water

breaktrough, water cut, GOR and pressure. Check the ECLIPSE data: Initial fluids in place (check

material balance) and calculate the well PI and the expected drawdown at the well.

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Rhombo exercise

Fluids: Calculate oil and gas compressibility in reservoir conditions.

Saturation functions: Calculate water oil & gas oil mobility ratio at saturation pressure

Initial state: Give the original fluids in place (oil, gas & water) in reservoir and stock

conditions. Are they compatible with PVT and SCAL data.

Natural depletion: Calculate the contribution of rock compaction & fluid expansion to

reservoir voidage (if there is no aquifer).

Well performance: Calculate the well productivity assuming a skin of 7.

Work to do...

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