4-chemical flood exercises_tutorial - oct- 2012.pdf

5/24/2018 4-Chemical Flood Exercises_Tutorial - OCT- 2012.pdf

1/37

ASP Modelling using STARS

Sudanese Petroleum Corporation-CPL October, 2012 Page 1

Creating a Chemical core flood datasetfor

STARS; CMG Thermal/Chemical Simulator

usingBuilder

Computer Modelling Group Ltd.

2012


2/37



Exercise 1 - Create a Model of the CoreFlood

1) Launch Builder and select as shown below:

Then Click OK twice.

2) Click on Reservoir >> Create Grid >> Cartesian, and then enter the information as

shown below:


3/37



Then click OK.

3) Change to Probe Mode, then click on the Specify Property. Then enter the following

values for the corresponding properties:

Grid Top: 1000 (layer 1)

Grid Thickness: 0.033375

Permeability (I, J and K): 2591

Porosity: 0.2494

Pressure: 89 kPa

Temperature: 31 C

Then click OK. Save the dataset as ASP.dat.

4) Under I/O Control, double click on Simulation Results Output. Under Initial Well,

change the selection to Values in mass and volume units (MASS).


4/37



5) Click on the Select button next to the Select Grid Variable, and select the following

parameters:

Oil Saturation

Gas Saturation

Water Saturation

Temperature

Pressure

Composition in oil phase

Composition in water phase

Water viscosity

Oil viscosity

Water relative permeability

Oil relative permeabilityWater phase molar density

Oil phase molar density

Water mass density

Oil mass density

Water phase resistance factor

Oil phase resistance factor

Local interfacial tension

Local capillary number

Natural logarithm of CAPN

Velocity vectors of oil, water, and

gas at reservoir conditions

(VELOCRC)

Composition of key component

used in the calculation of adsorbingcomponent ->Special Unit = PPM.

Component Adsorbed

Click Okonce all the parameters are selected.

6) To create a fluid model, click on Components and select "Add/Edit Components".

Once the Components and Phase Properties window appears, click on the Add/Edit

Componentsbutton.


5/37



7) In the Component Definition window, click Select from Library List, then select H2O then

click OK. Make sure the reference phase is set as Aqueous for this component. The

molecular weight, critical pressure and temperature are blanks so that the internal

defaults will be used. Click Apply when done.

8) Click the arrow next to the component name and add another component. Name the

new component Dead_Oil, set the reference phase to Oleic, critical temperature and

pressure to 0.0and molecular weight to 0.4 kg/gmole. Then click Apply then OK.


6/37



9) Click on the Density tab and enter 869.2 kg/m3 for Dead_Oil and click the Applybutton. Once again, the water properties are blank so that the internal defaults will be

used.

10)In the Liquid phase viscosity tab, enter the values as shown below:


7/37



Click Apply. A green check mark should appear for the Components section.

11)In the General tab, enter the reference and surface properties as seen below:

Once finished, click Applythen OK.

12)To create the relative permeability data, click on Rock Fluid on the tree view, then

double click on the Rock Fluid Types.

13)Click on the arrow next to Rock Type and select New Rock Type. Click onTools, then

select Generate tables using Correlations. Enter the values as seen in the table below.

Click Applythen OK twice.


8/37



14)Click on the Initialization button, then select "Do Not Perform Vertical Equilibrium

Calculations (VERTICAL OFF)".


9/37



15)Click on the Specify Property , find the property "Water Mole Fraction (H2O)and enter

a constant value of 1.0 Click OKtwice.

16)Click on Numerical section, then double click on Numerical Controls to bring up the

Numerical window. Enter in the following values:

First Time Step Size after Well Change DTWELL 0.001

Isothermal Option on ISOTHERMAL

Model Modulation TFORM ZT

Convergence Tolerance total residual CONVERGE) TOTRES TIGHT

Maximum Average Scaled Residual for all Equations TIGHT

Click Applyand then OK. Save the dataset.

17)Now that the base dataset is completed, theASP wizardcan be used to turn this into an

ASP dataset.

Click on Components >> Process Wizards. From the drop down menu, select "Alkaline,

Surfactant and/or Polymer". Information regarding the selected process will appear.

Click Next.


10/37



18)Under the Choose Model drop box, pick Alkaline, surfactant, polymer flood (add 3

components).

Once this option is selected, default values are used for the different parameters of this

process. We will keep the default values for most of them. The ones that need to be

change are shown in red boxes in the figure below. Click Nextonce the changes are

made.

19)In the next step, make sure the "Add new component for ...." are select for all 3

components. This will create surfactant, alkaline and polymer components in the fluid

model. Click Nextwhen completed.


11/37



20)In step 4, select the Rock Fluid Region Number 1 then click Next. This will create

interpolation set based on the relativer permeability of this rock type.

21)In step 5, copy the tables from the IFT.xls for the concentrations versus interfacial

tensions as shown below, then click Next:

Note:These are generic chemical values, so you can change them based on your lab

data.

22)In step 6, enter the values for the table as shown below. This is adsorption values for

surfactant in the presence of different alkaline concentrations. Also change the polymer

adsorption value to 30 at 0.1 wt. %. Once again, this can be changed based on your

default values. Click Nextwhen complete.


12/37



23)Step 7 is where you will enter viscosity of water at different polymer weight %. Once

again, the values below can be changed to your lab data. Click Finishwhen complete.

24)Now that all the components have been defined, we will go ahead and define the

injector and producer well, as well as the time span for the simulation run.

Click on Wells & Recurrent, right click on Wellsin the tree view and select New.


13/37



Define the new well as shown below:

Under the Contraints tab, add one constraint OPERATE MAX STW 10cm3/hr. For the

value, Builder will convert this to m3/day.


14/37



Under the Injected Fluid, make sure that it is injecting 100% water.

25)Repeat the process to define a producer with the name PRODN. The constraint for the

producer should be OPERATE MIN BHP 89.0 kPa.


15/37



26)For well perfoation, Expand the tree view for well INJTR and double click on 2006-01-01

PERF.

Change the Well index type to TUBE-END linear flow model and the radius to 0.05m

(5cm). Click Apply when complete


16/37



27)Under the perforation tab, insert a new perforation by clicking on the icon

Enter 1 1 1 then click Apply.

28)Click on the drop down menu at the top to change to the PRODN producer and repeat

the steps.


17/37



For the perforation, enter 11 1 1 then click Apply.

29)The last thing to do is to add a series of dates for the simulation run.

The range of dates are as follow:

0 to 1.144492 days : Waterflood

1.144492 to 1.882667 days : first ASP slug

1.882667 to 4.774792 days : first water chase slug

4.774792 to 5.05075 days : second ASP slug

5.05075 to 5.9170 days : second water chase slug

The first set of dates will be for the water flood portion which ranges from 0 to 27.4678

hours (0 to 1.144492 days).

On the tree view, double click on Dates. On the Simulation Dates window, click on Add a

range of Dates.

Leave the From portion as 0, and click on the little calendar button next for the To

portion. In the CMG calendar window, enter 1.144492 in the Days Since Simulation

Startbox at the bottom. Then click OK.


18/37



30)Change the step to 1 hour and click OK. There should be 28 new dates added.

31)Next, we will change the injection to ASP at the end of the water flood.

Expand the Wells tree view and double click on the injector INJTR. Change the date at

the top to 2006-01-02.125 (the last date).

Click on the Constraint tab, and check the Constraint Definition box. Then click on the

Injected Fluid and change the compositions to as follow:


19/37



These composition represent 500ppm polymer, 0.1 weight % surfactant and 0.1 weight

% alkaline. Click Apply when finished.

32)Next we need to add a range of dates to define the ASP period. Repeat steps 29 and 30,

except the date will start from 1.144492 days and the end date is at 1.882667 days.

Also remember to change the step to 1 Hour.

From To

33)Once the ASP flood period had been defined, the injector will switch back to the first

water chase phase.


20/37



Repeat step 31, this time change the dates to 2006-01-02. 8528199 (last date), and

change the injected fluid composition to 100% water.

34)Next is to add a series of dates to define the water chase period. Repeat steps 29 and

30, this time the from date will be 1.882667 days and the to date will be at 4.774792

days. Once again, make sure the steps are in 1 hour increments.

35)The second ASP slug will start at the end of the first water chase (after 4.774792 days)

and will contain twice the alkaline concentrations.

Repeat step 31, this time change the dates to 2006-01-05.75766. Change the injected

fluid compositions to the values shown in the table below:


21/37



Click Apply and OK when finished.

36)Next add a range of dates from 4.774792 days to 5.05075 days for the ASP flood period.

37)Change the injected fluid composition at 5.05075 days (2006-01-06.00507398) to 100%water.

38)Add a range of dates from 5.05075 days to 5.9170 days to define the water chase

period. Set the stop keyword at the end of this date. Save the dataset.

39)Run this dataset in STARS. Use the ASP.ses file to view the results.


22/37



EXERCISE 2: History Matching the Waterflood

Now that a model of the core had been created, the next step is to history match it with the lab data.

For the waterflood history match, first open up the model and set the stop date at 2006-01-02.125.

Rename this dataset as ASP_WF.dat(or something like that) and then re-run the model.

To do the history match, the water-oil relative permeability curves will be changed as well as the relative

permeability end points (KRWIRO and KROCW). However, the saturation endpoints will not be changed

as these came from the lab data. CMOST will also be used to assist in the history matching of this core.

Normally, multiple relative permeability curves will be generated as include files and these will be used

as different parameters in CMOST to history match. However, the generations of these include files can

be tedious and time consuming so we will use CMOST's ability to define a parameter with a function to

generate the different relative permeability curves.

1. Open up the ASP_WF.datfile in a text editor. Use the find function to look for the keyword

SWT. This is where the rel-perm tables are defined.


23/37



2. Each of the values under the Krwand Krowcolumn can be determined by the Corey equations:

Pkrw

oirwwcrit

wcritwrwirorw

SS1

SSKK

Pkro

orwwcon

orworocwrow

SS1

SSKK

Since we are not changing the endpoints, the only variable that we will change in this case is the

Pkrw and the Pkro.

3. Given the following parameters:

Swcrit = 0.306

Soirw = 0

Sorw = 0.313

Swcon = 0.306

Krwiro = 1

Krocw = 0.9062

So, the first krw value is defined as follow (using Pkrw = 3):

00.0306.01

306.0306.01K

3

rw

And the second value is:

5

3

rw 100398.40.0306.01

306.0329813.01K

Since CMOST allows for the definition of a parameter as a function, we will now input the

corey equation for each of the Krwand Krowvalues in the SWT table. The only number

that changes as you move down the Krw column is the

orwwcon

orwo

SS1

SS

value.


24/37



So you can manually put this in yourself, or copy and paste the tables from the CMOST-SWT.txt

file.

4. Once this is completed, scroll down the the end of the first SLT table and enter the following

lines:

KRWIRO this[1]=Krwiro

KROCW this[0.9062]=Krocw

This allows to change the end point scaling of the rel-perm curves.

5. Rename the file as ASP_WF.cmmfile. It is important to have the extension to be .cmmnow so

that it can be read by CMOST.

Open up Launcher and double click on the CMOST Studio 2011.** icon to open up CMOST

Studio.


25/37



6. Click on File >> New. Under the Task Type menu, select History Matching. Click on Browse

ands elect the base irf file (ASP_WF.irf). Click OKonce finished.

7. Next is the CMOST main screen. On the left are the different sections that will need to be

completed before CMOST can be run.

For the Master dataset, browse and select the ASP_WF.cmmfile. The base dataset should be

ASP_WF.datand the base session file should be ASP.ses. Once these are selected, there should

be a green check mark next to the General Properties at the bottom of the window.


26/37



8. Click on Parameterson the left hand side of the screen. This is where the parameters their

ranges of values will be set.

Click on theImport button. This import all the parameters from the CMM file. Alternatively,

you can also set up new parameters either directly in the CMM file or using Builder.

Once you have clicked Import,there should be 4 parameters that show up. They are:

- Krocw

- Krwiro

- Pkro

- Pkrw

The range of values for these parameters can be set in the candidate values section at the

bottom of the window.

Select Krocwand under the enter 1.0, 0.9062, and 0.8 as it's candidate values.

9. Select Krwiroand enter values of 1.0, 0.8, 0.6, 0.4, 0.35, 0.3, 0.25 for it's candidate values.


27/37



10.Select Pkro, and click on the Generate button. Enter the Minimum Value as 1.5, Maximum

Value as 2.5, and the number of values as 11. This will enter a range of values from 1.5 to 2.5 in

0.1 increments.


28/37



11.Repeat the steps for Pkrw. Once this is done, the red x should disappear from the parameter

section and we can move on to the next section.

12.For the Optimization, we will leave is as DECE. Note the other potential optimization methods

that are also available.


29/37



13.Next thing that will be defined will be the objective functions. Objective functions are what will

be matched in the task. In this case we want to match 2 things: oil production and injection

pressure.

Click on Inserton the right handside to define a new objective function. Rename the objectie

function to CumOil. At the bottom is the objective function terms that make up the objective

functions. For this term, leave the Origin Type as Well, Origin Name toPRODN, Property to

Cumulative Oil SC, and select the Prod.fhfas the field history file.

Click Insert again to defined a new objective function and this time name it BHP. For the

objective function terms, set it as Well - INJTR - Well Bottom-Hole Pressure. Select the

Inject.fhfas the field history file.

There should now be 2 objective functions (CumOil and BHP) and each with one objective

function terms.


30/37



14.The Influence matrixwill be leave as default.

15.Results observersallows for graphs of results from different runs to be displayed as CMOST is

running. For this case we want to see the cummulative oil produced as well as the injector BHP

(the 2 objective functions) during the CMOST run.

Click on the Import button, then select all the objective functionsthen click OK


31/37



16.Once that is done, the final step is to set up the Run Configurations. For this case, leave the

runs on the local machine and run 2 simultaneous jobs at a time.

Select STARS 2011.** as the simulator version and leave everything as default.

17.Save the task as Waterflood-HM.cmt. Then click Start Taskto start the CMOST run.

Once CMOST is completed, check the results and compare the most optimized runs to the historical data.


32/37



EXERCISE #3 - ASP History Match with CMOST

1. Load the base waterflood model (ASP-WF.dat) into text editor. Remove the STOPkeyword at

2006-01-02.125. Save the dataset as ASP_HM.datand re-run the dataset.

2. Once the history match is done, load the best matched waterflood dataset into text editor.

Enter the following after the DTRAPW and DTRAPN keywords for the 2nd interpolation set:

DTRAPW this[-3.5]=DTRAP2

DTRAPN this[-3.5]=DTRAP2

3. Repeat the same process for the 3rd interpolation set.

DTRAPW this[-2]=DTRAP3

DTRAPN this[-2]=DTRAP3

4. After the SLT table for the 2nd interpolation set, enter the following:

KRWIRO this[0.3]=krwiro

KROCW this[1.0]=krocw

SORW this[0.3]=SORW

5. Locate the KEYCOMP keyword and replace the values with:

KVTABLE 'Surfact'

KEYCOMP

**$

0 0

0 0

KEYCOMP

**$

this[200]=KvTab this[200]=KvTab

this[200]=KvTab this[200]=KvTab

This value controls the amount of reversible partitioning of the surfactant into the oil phase.

6. Find the keyword FREQFACfor surfactant. This value controls the reaction rate for irreversible

partitioning of the surfactant into the oil phase. There is also a reaction that governs the

decomposition of the polymer so make sure to locate the one for the surfactant (normally it is

reaction #2). Enter the following:


33/37



FREQFACthis[0.110672]=FreqFacsurf

Repeat the process for the reaction involving polymer:

FREQFAC this[0.02284]=frefacpoly

7. Finally locate the ADMAXTkeyword. This value controls the maximum adsorption capacity of a

rock to a certain component. Once again, there will be one for polymer and surfactant. Replace

the ADMAXT value with the following:

ADMAXTthis[10.1688]=AdMaxSur

ADMAXTthis[0.299081]=AdMaxPol

8. Remove the STOP keyword that was placed at the end of the water flood. Save the file with a

.cmmextension in the same folder as the previous .cmmfile for water flood.

9. Open up the .cmt file used for the waterflood match. In the general task pane, change the

master dataset file to the newly created asp history match .cmmfile. Also change the base

dataset to ASP_HM.datand the base irf to ASP_HM.irf.

10. In the Parameters section, delete all the parameters, then click Import to bring in the new

parameters that were created from steps 1-6. The range for candidate values are as follow:


34/37



AdmaxPol: 0.05 to 0.3 (in 0.025 intervals)

AdmaxSurf: 1, 1.5, 2, 3, 5

DTRAP2: -3.4 to -2.2 (in 0.1 intervals)

DTRAP3: -2 to -0.4 (in 0.1 intervals)

KvTab: 10, 20, 50, 100SORW: 0.18, 0.21, 0.24, 0.27

krwiro: 0.4 to 0.8 (in 0.1 intervals)

krocw: 0.7 to 1 (in 0.1 intervals)

FreqFacSurf: 0.06, 0.08, 0.1, 0.15, 0.2

freqfacpoly: 0.01 to 0.1 (in 0.01 intervals)

11. In the Objective Function screen, add a new objective function and name it CumSurf. For the

objective function term, the Origins = WELLS, Origin Name = PRODN, Property = Cumulative

Water Mass (Surfact)SC.

Add 2 more objective functions, one for cumulative polymerand one for cumulative alkalineby

repeating the process above.

Finally, the end date for all the objective function terms need to be changed to 2006-01-

06T21:13:03.

12. In the Results Observers section, click the import button and add new plots of cumulative

surfactant, cumulative alkaline and cumulative polymer.

13.Save the cmt file as Chemflood.cmtand click on Start Task.


35/37



Exercise #4 Add Shear Dependence Viscosity

1. Using the table below, calculate the velocity from the shear rate by using the following

equation:

10066*

****

SRF

SlkrkSR

where v = velocity (cm/sec)

SR = shear rate (1/sec)

K = Absolute Permeability in Darcy = 2.591 D

= Porosity (factor) = 0.2494

Sl = fractional liquid saturation

SRF = C*((3n+1)/4n)^((n-1)/n)

where n =shear thinning power exponent (default = 0.5)C = constant value (usually equal to 6

ShearRate1/S

Slug viscosity (cp) Velocitycm/sec

Velocitym/day

500ppmPolymer

1000ppmPolymer

1500ppmPolymer

0.6624 5.2 7 101.10206E-05 0.009522

6.624 4.8 5 9.20.000110206 0.095218

66.24 3.2 3.8 6.1 0.001102057 0.952177

2. Next, the polymer viscosity required to achieve the viscosities in the table above must be

calculated using the STARS mixing rule:

3. ii fxulnln

where = phase viscosity

= viscosity of component i

= non-linear function for mole fraction of component i

a)

First we'll need to scale the fxi factor according to the mole fraction of polymer injectedVSMI

XFUN

C 0 0.141793 0.283587 0.425236 0.483117 0.54105 0.626499 0.711947 0.797396 0.882844 0.968293

x 0

2.254470E-

07

4.508940E-

07

6.763410E-

07

9.017880E-

07

1.127235E-

06

1.352682E-

06

1.578129E-

06

1.803576E-

06

2.029023E-

06

2.254470E-

06

Since we are injecting at a polymer mole fraction of 1.12862e-6, we can see that the

mixing function is somewhere between 0.54105 and 0.6265. To calculate the actual

value, we will do a simple linear interpolation:


36/37



Linear interpolation factor = (1.12862e-6-1.1272e-6)/(1.35286e-6 - 1.1272e-6) = 0.00614

new fxi = 0.00614 * (0.6265-0.54105)+0.54105 = 0.54157

b)

Then calculate the R ratio. This ratio calculates the nonlinear mixing function fx for the non-polymer components.

R ratio = ( 1-0.54157)/(1-1.12862e6) = 0.45843

c) Now, calculate the polymer viscosity using the following formula:

poly

surfsurfalkalkww

polyfx

RxRxRx

lnlnlnlnexp

Notice that the R ratio needs to be multiplied to the mole fraction of individual components

to scale it to that specific mole fraction.

= 5.2

uw= ualk= usurf= 0.8177

fxpoly= 0.54157

R = 0.45843

xw= 0.9994977650

xalk= 0.00045144/

xsurf= 0.00004965900

Using the numbers above, the polymer concentration should come out to be 24.89.

Repeat this same calculations for the other shear rates, and the velocity versus polymer

concentration should look as follow:

**Velocity Viscosity

**m/day cp

0.009522 24.89

0.095218 21.34

0.952177 9.99

Create a table using the keyword SHEARTAB and add this table to the dataset using the text

editor.

The dataset should look something like this:


37/37



The SHEARTAB will be applied to the last component specified with the VSMIXCOMP

keyword so make sure that polymer is the last component specified with this keyword.

Run the dataset and compare the results. Note that in the core lab flood, the velocity is

constant so there will not be much effect on this. When this data is used in a field model, the

injection rate will be mostly positively affected (increase injectivity due to lower viscosity).

4-chemical flood exercises_tutorial - oct- 2012.pdf

Documents

chemical flood exercises

asp modelling

reference phase

phase properties window

oil phasecomposition

water properties

component definition

thenew component dead