Economic Calculations Any decision an E&P company makes is an integrated process that involves economics, planning, finance and risk management. Therefore, an understanding of how the technical decisions made might impact the business goals is important. An economic evaluation is done to justify a decision that will demand a capital cap ital ependiture !drilling new wells, e"uipment purchases like compressors, workovers# or impact operational costs. Additionally, Additionally, short$term !monthly# economic goals need to be balanced with the longer$term !%$ year# financial objectives objectives of the company. 'ltimately, 'ltimately, management also uses economic evaluations for corporate budgeting, government and investor reporting, and valuations of oil and gas properties. 'ncertainty and risk both play huge roles in any E&P company(s decision$making. decision$making. Economic uncertainties !e.g., in oil prices# have to be taken into account, which can have a significant impact on the economics of any a ny project. The goal of this section is to provide some basic knowledge and techni"ues for performing investment analysis for geoscientists geoscientists and engineers. At At the end of this section, they should be able to understand the concepts and calculations needed for an eploration or field$development project. )nvestment and economic analysis can be divided into two main areas* cash flow analysis and economic decision measures. Basic Cash Flow
A basic cash flow takes a production estimate and applies price to calculate a revenue stream. +rom this revenue stream, we subtract royalties and operating epenses to achieve an operating income. apital is then removed to create a -efore$Ta -efore$Ta ash +low !-T+#. )ncome taes are then calculated, and the After$Ta After$Ta ash +low !AT+# !AT+# is created. evenue
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Production 0olume olume 1 Price
2perating )ncome /
evenue 3 !oyalty 4 2perating costs#
-T+
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2perating )ncome 3 apital ependitures
Taable Taable )ncome
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2perating )ncome 3 5epreciation !55&A#
AT+ AT+
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-T+ 3 Taes Payable
6here* -T+ / -efore$Ta ash +low
AT+ / After$Ta ash +low 55&A / 5epreciation, depletion and amorti7ation
Production Volumes
)n Petrel, production volumes can be obtained from either the E8)P9E or +ront9im reservoir simulators. These volumes can be oil, water, gas, or natural gas li"uids !:;8# production, or water and gas injection values. Prices
Price is the monetary value received for each ea ch barrel of oil or cubic foot of gas produced and sold. 9econdary by$products !:;8s# may also be sold from some reservoirs. Prices may be kept at a constant value or escalated over time. Escalations are predictions of how the price will change based on market conditions. The "uality of the hydrocarbon being sold !AP) density, absence of impurities like <=9, etc.# can also affect the product price. Royalties
oyalty is value deducted from the revenue stream, which usually has no obligation toward covering epenses. )t is considered to come >off the top?, after product "uality adjustments, but before operating costs or investments are deducted. @any different formulas are used for the calculation of royalties, which are dep endent on the fiscal regime of a particular region. Operating costs
2perating costs are the day$to$day costs of operating a property and maintaining production. Typical Typical charges would include fluid processing costs, lease electricity, electricity, chemicals, water disposal, and overhead. They are identified with a specific property and might include lease maintenance, treating fluids, general repairs, fuel and electricity, electricity, and secondary or enhanced recovery operations. 2verhead type charges such as salaries and office costs are usually grouped with operating epenses in a basic cash flow analysis. They are normally deductible for income ta purposes. ommon methods of scheduling operating costs over time are* •
0ariable !Bbbl or Bmcf#
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6ell 6ell count !BwellBmonth or BwellBday#
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+ied !@Bmonth or @Byear#
Capital investments
apital consists of investments for drilling, eploration, e"uipment and facilities. 'sually broken down into Tangible and )ntangible categories, they are considered spent in the scheduled year for the -efore$Ta ash +low, and recovered over time for the After$Ta ash +low. Tangible investments are e"uipment purchases, such as pumping units, pipelines, compressors, and buildings. They often have salvage value. )ntangible investments are drilling fees, mud and chemicals, logging, and other non$e"uipment charges. They typically have no salvage value. osts to abandon an area or location are sometimes grouped with capital investments. 9pent at the end of the life of a project, they may be offset by any recoverable e"uipment sold as salvage. Income or Federal Taxes
2nce an 2perating )ncome has been established, income taes should be calculated. )t is at this point that tangible assets are depreciated over time, reducing the income stream available to be taed. The ta rate is applied to Taable )ncome, taes are subtracted, and the After Ta ash +low is created. epreciation! depletion and amorti"ation epreciation is a non$cash epense that reduces the value of an asset as a result of wear and tear, age, or obsolescence. @ost assets lose their value over time !in other words, they depreciate#, and must be replaced once the end of their useful life is reached. epletion is concerned with the ehaustion of mineral reserves as a result of production of these reserves. #morti"ation is the writing off of an intangible asset investment over the projected life of the assets. ecision $easures
)n order to assess an economic calculation or to compare competitive plans, one should apply several decision measures to determine the profitability. These measures should, at the minimum* Allow one to distinguish between acceptable and unacceptable projects by evaluating them with established standards and practices. •
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Enable one to rank the best investment project from a group of projects.
;ive some insight into the outcome of a proposed project on the overall profit of the company. •
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5etermine if the project adds value or return to the investors.
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And give a measure of rate by which the revenue is generated in the project.
Economic decision measures are a range of different indicators defined and employed for the comparison process of a group of projects. Each has its advantages and disadvantages. 9ome decision measures embrace the concept of time value o% money . @oney is worth less, the longer you have to wait to receive it. )n the same regard, money received yesterday is worth more than money received today. onsider that you can take yesterday(s earnings and invest it, earning additional value. )f you have to wait to receive money, you must delay the investment, therefore potentially losing money. Also consider that inflation will erode the value of money. 5ecision measures can generally be grouped into three categories* C. Value creation measures * These summari7e future net cash flows in today(s money !for eample, :et Present 0alue !:P0#, )nternal ate of eturn !)#, ProfitB)nvestment ratios !P)##. =. &urvival $easures * These place an importance on short$ and medium$term risk impact !for eample, Payout Period, risk management, Total capital eposure#. %. Competitive measures * These can be supply cost measures like break$even prices, or hurdle rates or financial measures such as earnings or return on capital employed !2E#. Terminology
The economic indicators can be described as follows* 'et present value ('PV) / present value of cash inflows 3 present value of cash outflows !or minus initial investment.# ;enerally a project with positive :P0 adds value to the investors in the project, and conversely, a negative :P0 will not generate an ade"uate return. •
Rate o% return (ROR) or internal rate o% return (IRR) is the single discount rate that produces a :P0 of 7ero. )t is also described as the discount rate that e"uates the present worth of cash flows to be e"ual to the present worth of the investments. •
Pro%it to Investment Ratio (PIR) 3 also known as the eturn on )nvestment !2)#, this indicator is similar to the 5P). )t simply divides total :P0 by total capital. Dnown as the >bang for the buck? indicator, it is very useful for ranking projects when capital is limited. •
iscounted Pro%ita*ility Index (PI) is a measure of investment efficiency, and is used to evaluate multiple rates of return projects relative to the investment re"uirements. onsistent use of the same discount rate is necessary when comparing projects by using 5P). This indicator is sometimes called P). •
Pay*ac+ period is the time to return an investment. )t is calculated from the net cash flow stream. The point at which the cumulative net cash flow stream becomes positive is the Payout. •
,sing the $era+ Economics process
'se the $era+ Economics process to create or edit an economic model that can be used to compute economic indicators. ou can compute economic indicators for the simulation cases listed in Petrel(s Cases pane, and the results are added to the Results pane. ou can perform economic valuations for single wells, groups, or fields, by selecting the appropriate identifier from the Results pane and dragging it onto the omains bo on the Calculation tab in the $era+ Economics dialog bo. )n a typical economic run, you can combine wells, groups, and fields together. The data for all valid domain items are added together for each simulation in the run. The $era+ Economics process automatically obtains the capital ependiture profile from the simulations for development or infill drilling and workovers, if these options have been used. Preparing your data %or economic simulations
)f performing economic calculations, it is strongly recommended to re"uest the E8)P9E or +ront9im simulations to output additional data used to enhance the economic calculations. To do this, open the &imulation folder on the Processes pane, and then double$click the 5efine simulation case process to open the 5efine simulation case process dialog. ;o to the Results tab, and then select the Economics check bo in the -ine .raphs (&,$$#R/) option group.
6hen you select the Economics check bo and run an economic calculation, the simulator will output the following summary vectors* •
F$0PR1 Total number of production wells currently flowingF
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F$0E'1 Total number of injection wells currently flowingF
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F$0R1 Total number of drilling events during this timestepF
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F$0T1 Total number of drilling events in totalF
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F$00O1 Total number of workover events during this timestepF
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F$00T1 Total number of workover events in total.
Creating an economic calculation run
This section describes how to build and run an economic calculation. ou can set up an economic$calculation run from the &imulation folder in Petrel(s Processes pane, or from within the Process $anager . To set up a run from within the Processes pane* C. 2pen the &imulation folder in the Processes pane.
=. 5ouble$click to open the Merak Economics process. The In%o tab provides a brief description of how the @erak Economics process works. %. lick the Calculation tab to define the basic parameters of your economic calculation !see 5efining basic economic$calculation parameters#. This includes choosing whether you will create a new run or overwrite an eisting one, choosing an economics model, choosing the identifiers !wells, groups, or field# for which you want to perform calculations, and choosing the simulations that you want to use for the calculation.
G. onfigure the settings for your economic calculation !see onfiguring settings for an economic calculation#. This includes defining the start date of your calculations, choosing how drilling costs will be defined, setting up Peep Eport file parameters if desired, and choosing the data$sampling fre"uency for your simulation.
. 5efine mappings for Ethane, Propane, and -utane if desired !see 5efining mapping for ethane, propane, and butane#.
H. 2nce you have set up your economic calculation as desired, you can do one of the following* lick the Run button to perform the calculation for the currently selected run. 6hen you perform a run, all input data is sampled into the specified fre"uency and passed on to the @erak Economic Engine, which performs the economic calculations, and then passes the results back to Petrel for inclusion in the Results pane. Any changes you have made to the run(s properties are saved, and will be reflected the net time you select that run on the Calculation tab. •
lick the #pply button to apply any changes that you have made to the currently selected run, but leave the $era+ Economics dialog bo open. These changes are saved, and will be reflected the net time you select that run. •
lick the O2 button to save any changes that you have made to the currently selected run, and close the $era+ Economics dialog bo. These changes are saved, and will be reflected the net time you select that run. •
lick Cancel to close the $era+ Economics dialog bo without saving any changes that you have made to the currently selected run. •
e%ining *asic economic3calculation parameters
'se the Calculation tab of the $era+ Economics dialog bo to define the basic parameters of your calculation, including the economic model that will be used for the calculation, the wells, groups, or field for which the calculation will be performed, and the simulations whose data will be used as inputs for the run.
Tip* 6hen you open the $era+ Economics dialog bo, the last$used run is automatically loaded, and the settings from that run populate the Calculation , &ettings , and $apping tabs. This enables you to create a new run that is similar to a previously created run, by selecting the run upon which you want to base your new run, changing it as desired, and then creating a new run based on your changes. 4ow to de%ine *asic economic3calculation parameters
hoose whether you want to create a new run, or overwrite an eisting run* C. Overwrite existing run1 9elect this option if you want to base your run on a previous economic calculation run. 6hen you select this option and choose an economic run from the drop$down list, the Calculation , &ettings , and $apping tabs are updated with that run(s properties. At this point you can*
Per%orm a run using the current settings , overwriting the results for that run. ou may want to do this if the data in the simulations selected for the run has changed since you last performed the economic run, and you want your run to reflect those changes. •
Change the selected run5s properties as re6uired! and then run it again , overwriting the previous run results and changing the run(s properties. hanges might include adding wells to !or deleting them from# the omains list, basing your run on a different simulation, basing your run on a different set of drilling costs, etc. 6hen you chan ge a run, its properties are not updated until you click the Run, #pply, or O2 buttons. •
Create a new run *ased on the currently selected run !see below#. 9elect an eisting run whose properties are similar to the new run you want to create. This saves work, minimi7ing the number of changes you will have to make in order to create the new run. •
=. Create new run1 After selecting an eisting run and changing its properties on the Calculation , &ettings , and $apping tabs, select this option to create a new run based on your changes. Type a name for your new run in the adjacent field, and then click the Run, #pply, or O2 buttons to save your new run. 6hen you save a new run, it is added to the Overwrite existing run drop$down list, and the run upon which it was based remains unchanged. )n the Economic $odel option group, choose the economic model upon which you want to base your calculation. )f necessary, you can edit a model before selecting it, or create a new model !see Editing or creating an economic model#. %. 9pecify the identifiers !wells, groups, or field# for which you want to obtain data, by adding them to the omains bo. ou can perform a run for selected wells andBor groups from one or more simulations, or for an entire field. The sum of all the production, injection, and drillingBworkover outputs for all items in the 5omains list is used for an economic run. To add identifiers to the omains bo, select them from within the Identi%ier folder in the Results pane, and then click the #dd selected domains button. •
Tip* To multi$select identifiers from different points in the tree, press and hold the Ctrl key, and then select all the desired identifiers. To select all the identifiers between two points, select one, then press and hold the 7&hi%t8 key, and select anotherF the two selected identifiers and all those between them will be selected.
To remove identifiers from the omains bo, select !or multi$select# them, and then click the Remove selected domains button. •
6hile you can perform a run for different combinations of wells or groups, generally you will not combine these identifiers with the Field identifier in the same run. As a result, if you are adding wells or groups to the omains bo, you will need to remove the Field identifier before performing the run. •
G. 9pecify the simulations from which you want to obtain data for your economic calculations* To add simulations to the &imulations bo, select them from within any of the cases on the Cases pane, and then click the #dd selected simulations button. ou can add all the simulations within a case by selecting the case and then clicking the #dd selected simulations button. •
)f you have performed a dynamic data calculation on a case, you can also add that calculation to the &imulations bo for inclusion in your run. •
To remove simulations from the &imulations bo, select !or multi$select# them, and then click the Remove selected simulations button. •
. 2nce you have finished defining your economic$calculation parameters, configure the settings !see onfiguring settings for an economic calculation# and define the mapping !see 5efining mapping for ethane, propane, and butane# if desired before running your simulation.
Editing or creating an economic model
6hen performing economic calculations in Petrel, after selecting an economic model, you can view or edit the contents of that model, create a new economic model, or delete a previously created model. To perform any of these operations, click the Edit9Create button on the Calculation tab of the $era+ Economics process dialog bo to open the $era+ Economics $odule dialog bo.
4ow to view the properties o% an economic model
C. 9elect the model from the Economic $odel drop$down list whose properties you want to view. =. lick the .eneral, Operating Cost or Capital Cost tabs to view the data on those tabs. %. Edit the values on any of those tabs as appropriate and press #pply or O2 when done. 4ow to edit the properties o% an economic model
C. 9elect the model from the Economic $odel drop$down list whose properties you want to edit. =. lick the .eneral tab*
9elect the desired fiscal model from the Fiscal $odel drop$down list, which contains a list of models representing over CII fiscal regions, defining how the royalty, ta rates, etc., vary for each one. •
2n the Oil Price tab, select the ,se Existing Oil Price File option button if you want to base the oil prices in your model on a saved oil$price file. Then select the desired price file from the drop$down list. •
)f price files are not available !or if you want to create a custom price array#, select the ,se Price #rray option button, and then create an array by clicking the first row in the ate column, then choosing the desired month and year. Then type a price value for that month. ontinue until you have added all the desired prices to your array. •
2n the .as Price , Propane Price , Butane Price , and Ethane Price tabs set up prices in the same way as you did for oil prices. •
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lick the #dvanced &ettings button to open the #dvanced &ettings dialog bo*
)n the iscount Rate field, type the discount rate percentage that you want to use for economic calculations or analysisF •
)n the Revenue Interest field, set the :et$Profit working$interest percentages for your asset !for '.9. and anadian regions only#F •
)n the Cost Interest field, set the operating$cost and all other capital$cost interest percentages for your asset !this assumes that you will be using the same percentage for all of these interests#. •
%. lick the Operating Cost tab*
)n the Fixed Operating Cost option group, specify fied operating costs for each active producer or injector well per month. Also add any other fied operating costs on a per$ month basis !this could be for a well, a group, or a field#. •
)n the Varia*le Operating Cost option group, specify the operating costs for oil, gas, water, or injection, on a per$production$unit basis. •
)n the '.- Operating Cost option group, specify the operating costs for propane, butane, or ethane, on a -2E basis. •
G. lick the Capital Cost tab to specify your capital ependitures*
lick the first row in the ate column, and then choose the desired month and year for your first ependiture. •
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)n the #mount column, specify the amount of the ependiture.
lick the drop$down list in the Type column and choose a cost type. This is important because it determines how this cost will be treated in economic calculations !e.g., e"uipment depreciation or epensed capital items#. apital types can vary between fiscal regions. The day of the month which the cost is incurred does not matter for economic calculation purposes. •
'se the rilling and 0or+over fields to input any drilling or workover costs on a per$ well basis. Take the total costs and determine average values, and then input them here. These costs are multiplied by the number of drillingBworkover events in a given period !monthly, "uarterly, semi$annually, or annually# in order to complete additional capital ependitures over that period. This is in addition to any costs incurred in the Capital Expenditure grid. •
. )n the $era+ Economics $odule pop$up dialog bo, click O2 to save the changes to the current model, or type a different name to create a new model based on your changes. 4ow to create a new economic model
C. 6orking in the $era+ Economics $odule dialog bo, select the model from the Economic $odel drop$down list upon which you want to base your new model.
=. Edit the model if desired !see
C. 6orking in the $era+ Economics $odule dialog bo, select the model from the Economic $odel drop$down list that you want to delete. =. lick the elete button. A pop$up message asks you to confirm the deletion. %. lick O2 to delete the model. Con%iguring settings %or an economic calculation
The &ettings tab of the $era+ Economics process is used to configure the settings for the economic calculation. This includes defining the start date of the calculations, choosing how drilling costs will be defined, setting up Peep Eport file parameters if desired, and choosing the data$sampling fre"uency for your simulation.
4ow to set when you want calculations to start %or an economic run
Each simulation has its own start date, and each data set also has its own start date. ou can use the ate &ettings option group to define the date from which you want data passed for an economic run* e%ine %rom simulation1 6hen this option is selected, the run looks at the first result output date from the simulation. •
e%ine manually1 6hen this option is selected, you can use the Valuation ate drop$ down calendar to set a start date. )n this case, the calculation engine takes data starting •
from the selected date, and then uses the data from that date forward to calculate the value for the first month. :ote* The Valuation ate chosen here corresponds to the iscount ate used in @erak Peep. 4ow to override the economic model5s drilling costs
:ormally, drilling costs come from the economic model !defined as Capital Cost#. ou can override these costs if desired, replacing them with costs from the 2sprey isk Plug$ in, or with an average cost that you define. To override drilling costs, select the Override Economic $odel5s drilling cost check bo, and then* 9elect the e%ine %rom Osprey Ris+ Plug3in option to use 2sprey isk Plug$in costs from the Input pane. 9elect a PJI ost, PI ost, or PCI ost log, and then click the #dd well log button to use the drilling cost from that log. 6hen you select an 2sprey isk well log, the drilling cost for that well is displayed in the #verage rilling Cost field, and this value is used for every well in the run. •
9elect the e%ine manually option button to input your own drilling cost. 6hen this is selected, the #verage rilling Cost field becomes available. Type a value that will be used for every well in the run. •
6hen the $era+ Economics process is run from the Process $anager, you can also enter a variable name !that was previously defined in the workflow# as your #verage rilling Cost value. The $era+ Economic p rocess will then look for the value associated with that variable, and use it in the calculation. 9ee the 'sing the @erak Economics process within the Process @anager section for more information. 4ow to send results o% an economic run to a Peep Export (PE:) %ile1
9elect the Peep Export check bo, and then specify the path and name of the Peep Eport !1.pe# file into which you want to add the economic run. The $era+ Economics process will create the Peep Eport file, which you can then import into @erak Peep for analysis. ou cannot import Peep Eport files generated from @erak Peep back into the $era+ Economics process. 4ow to set the data3sampling %re6uency
6orking in the ata &ling Fre6uency option group, select one of the option buttons to define the fre"uency at which input data is sampled from simulations. )f the sample fre"uency is larger than the fre"uency of input data, then the result will be less accurate. e%ining mapping %or ethane! propane! and *utane
9ome by$products are fre"uently recovered as part of field operations. Eamples of these include natural gas li"uids !:;8s# and condensate. )t is common practice to establish the volume of :;8s recovered by applying various empirical formulae, using the 5ynamic 5ata alculator . The results of these calculations may then be used on the $apping tab to account for the economics associated with :;8s.
)f desired, you can specify which outputs from production streams that you will use to represent Ethane, Propane, and -utane. This process is optional, and is only re"uired if you have :;8s in your recovery stream. 4ow to map '.-s to production outputs
C. 9elect the check bo net to the natural gas li"uid for which you want to create a mapping !e.g., Ethane !=##. =. )n the &ource drop$down list, select &imulation or Calculator to define the type of property you will be using. %. +rom the Results pane, select the name of the result property that you want to use to represent the current :;8. G. lick the #dd property button on the current row to populate the Property field with the property that you selected. )f the property that you added is non$component$based !e.g., :;8 production rate#, then that rate will be used to represent the :;8. •
)f the property that you added is component$based, then the Component field becomes available, and you will need to select a component to represent the :;8 •
. )f the property that you added was component$based, select a fluid from within the Fluid Identi%ier folder in the Results pane, and then click the #dd component button to add the selected component to the Component field.
H. epeat the previous steps to map :;8s for Propane !%# and -utane !G#.
Visuali"ing the results o% economic calculations
After you run an economic calculation, the results are stored in the Economic Indicator and Economic Pro%ile folders in the Results pane.
4ow to view results o% economic calculations
C. )nsert a new +unction window from the 6indow menu !0indow ; 'ew %unction window)< =. 9elect the check bo!es# net to the desired economic run!s# from the Cases pane. Any associated indicators, profiles, or rates will become available on the Results pane !the names of those that are unavailable are grayed$out#. %. 9elect the check boes net to the desired indicators or profiles to view them in the window.
ates obtained as a result of @erak Economics calculations are stored in the same ates folder as rates from the simulation!s#. These rates account for the effects of the fiscal model used in the economic calculation. ,sing the $era+ Economics process within the Process $anager
The $era+ Economics process can be used inside the Process @anager to automate the generation of economic results. )n addition, it provides facilities for maintaining an au dit trail to understand who did what, when and how. )t also forms the basis as to how uncertainty in economic parameters !e.g., drilling capital costs or oil price# can be modeled efficiently. The following eamples illustrate the use of the $era+ Economics process in the Process @anager. Example = (Running the Economics Process once over a set o% cases)1
This eample shows how to generate an economic run for every case within a folder !e.g., after running an 'ncertainty 6orkflow#.
The @erak Economics dialog bo from within the 6orkflow will look like the eample below. :ote that the simulation in the &imulations bo corresponds to the variable name in the Child re%erence field of the Process @anager !above#.
-elow is a sample output of the result of this run. :ote that each simulation has a @erak Economic run with the name specified in the above dialog.
Example >1 (Running several $era+ Economics processes per Case)1
This eample shows how to analy7e uncertainty in a parameter in the economic model. )n this eample, each of the three @erak Economics process statements in the workflow will have a different run name !<);<, -A9E, and 826# assigned to it, and each of these runs will use a different economic model that corresponds to high, b ase and low oil$price scenarios.
Example ?1 (,sing varia*les)1
ou can substitute both 6ell 5rilling cost and un :ame with variable names. The run name in the process can be a string variable, allowing the name of the run to be controlled from the workflow. )n this scenario, if you create a 9tring variable with the name '::A@E and use this as the run name in the @erak Economics dialog bo, then a run will be created called '::A@E, which can be edited in the normal way. '::A@E? where the simulation to use is set as >0ariable A?. The illustrations below show how new runs can be created by the Process @anager. This can help you organi7e your various economic runs so that you can easily identify them.
Example @1 (,sing well logs to populate the varia*les in a wor+%low)1
This eample shows how you can use specified well logs to populate the variable in a workflow. )n the Process @anager, add a reference, adding the variable and well log that you want to associate with that variable !in this case, we are associating three different values with the same variable.
A single economic run can be used, provided that the variable name is provided as the 2sprey isk Plug$in well log !below#.
