3D volumetrics uses a.docx
Transcript
3D volumetrics uses a Grid model for the calculations. To open the Volumetrics dialog box, do one of the following: Click the Grid under the relevant Grid model in the Data tree, and then select Volumetrics ➥ Volumetrics... in the Task pane. From the Workflows pane, expand Grid model ➥ Volumetrics ...
3D volumetrics uses a Grid model for the calculations. To open the Volumetrics dialog box, do one of the following: Click the Grid under the relevant Grid model in the Data tree, and then select Volumetrics ➥ Volumetrics... in the Task pane. From the Workflows pane, expand Grid model ➥ Volumetrics in the Jobs tree, and then select Volumetrics. The Volumetrics dialog box has four tabs: General Tab Calculations Tab Variables Tab Report File Tab General Tab In the General tab the volumes to be calculated are set up. A zone is defined as the thickness between two horizons. A job can be specified to only perform volume calculations and report on a subset of the grid model. Output Type in a prefix that will be used for all output parameters, zone maps, and total maps. Zones Select the zone, or zones, to be used. Region Index Click the Parameter drop-down list to select a discrete parameter defining a region partition. If the selected parameter is an ordinary discrete parameter, the associated list in the dialog box is populated with the discrete codes or labels. If the selected parameter is a Region model, the associated list in the dialog box is populated with the region names. Attributes defined in the region model can then be used to populate settings in the Variables tab of the dialog box, as described in the Variables Tab section of this Help page. The use of region models in RMS is explained in the Working with Regions page. Facies Click the Parameter drop-down list to select a grid parameter defining facies. License Boundaries Select one or more license boundaries to use. A closed, non-collapsed, polygon must be present under the License boundaries data object under the Cultural data folder in the Data tree. For information on how RMS handles the boundaries, see Truncated Cell Volumes in Appendix N - Volume Calculations. Calculations Tab Main Types To choose which calculations to be run one or more of the Main types must be selected first: Oil/Condensate Gas Totals Subtypes The volume calculations, Subtypes, which can be run are: Bulk volume Net volume Pore volume Hydrocarbon pore volume (HCPV) Stock-tank oil initially in place (STOIIP) Associated gas in oil zone Gas initially in place (GIIP) Associated liquid in gas zone Recoverable volume The different options are listed in the following table. Volumetrics calculation Oil/Condensate Gas Totals Bulk X X X a Net X X X Pore X X X HCPV X X  STOIIP X   Associated gas X   GIIP  X  Associated liquid  X  Recoverable X X  a The Totals bulk volume is seen as the geometric bulk volume and is not dependent on variables such fluid contact and formation variables. The formulas used to calculate the different volumetrics options are listed in the following table. Formulas used to calculate the different volumetrics options The variables used in the formulas are listed in the following table. Vbulk = Bulk Volume N/G = Net/Gross Vnet = Net Volume ϕ = Porosity Vpore = Pore Volume Sw Water Saturation HCPV = HydroCarbon Pore Volume Bo = Oil Formation Volume Factor HCPVoil = HydroCarbon Pore Volume of Oil Bg = Gas Formation Volume Factor HCPVgas = HydroCarbon Pore Volume of Gas GOR = Gas-Oil Ratio STOIIP = Stock-Tank Oil Initially In Place LGR = Liquid-Gas Ratio GIIP = Gas Initially In Place RFo = Oil Recovery Factor Recoverableoil = Recoverable Oil Volume RFg = Gas Recovery Factor Recoverablegas = Recoverable Gas Volume  For each calculation, three outputs can be selected: Parameter - creates a new grid parameter under the associated grid. Each grid cell will have a value equal to the cell volume. Output name will be [Prefix]_[Main type]_[Subtype]. Zone map - creates a thickness surface for each zone. For each interval, a 2D grid cell in the map will have a value equal to the height of the oil or gas column (for example, the thickness of HCPV in each cell). Output name will be [Prefix]_[Main type]_[Subtype]. Total map - creates a thickness surface that is the sum of the individual maps. Output name will be [Prefix]_All_Zones_[Main type]_[Subtype] Pre-calculated Bulk Volume If a bulk volume parameter has already been generated in a previous volumetrics calculation, this parameter can be used to speed up later calculations. By using such a Pre-calculated bulk volume parameter, you speed up the calculation of volume for a subset of the pre-calculated volume (that is, zones, regions facies codes, and/or license boundaries). This option is also useful if you want to alter the formation and fluid variables. However, there are certain constraints when using the pre-calculated bulk volume option: All licenses must be deselected. You are not allowed to modify contacts after the bulk parameter has been selected. If the Main types chosen are Oil/condensate + Gas, Oil/condensate + Gas + Totals or if none of them are chosen, the Pre-calculated bulk volume option will not be available. Will not affect map calculations. The parameter selected from the drop-down list in this tab can be used as input to an Uncertainty/Sensitivity Setup (see also Uncertainty/Sensitivity Setup). Area Average Area and average thickness - Generate area statistics by selecting the Area and average thickness check box. The area is calculated from the projected area, and based on the surface dragged into the Map layout drop site. The average thickness is calculated using true vertical thickness (TVT). These are output to the report file (Document or Tabular). Area and average thickness is only calculated per license boundary, if used, otherwise it is calculated per zone. Note Where the Report file output calculate Totals the Area And Average Thickness columns will say N/A in the text file output, or contain empty cells in Excel output. Adding up values from several zones that are not completely horizontal will produce numbers that are inconsistent with the total area and thickness, contrary to what might be expected. Other Create discrete parameter - If you have selected an appropriate calculation (HCPV, STOIIP, Associated Gas, GIIP, Associated Liquid and/or Recoverable) you can request the creation of a Discrete fluid parameter. This grid parameter has cell values according to the fluid contact (that is, it describes where oil, gas, and water are found in the grid model). The parameter cell values consists of three different codes: The cell center is in the gas zone, above the gas/oil contact The cell center is in the oil zone, below or at the gas/oil contact, above or at the oil/water contact The cell center is in the water zone, below the oil/water contact Negative cell volumes - Negative volumes in cells can appear when the cell is "wrapped". You have the choice of setting the negative values to zero or allowing negative cells. If you allow negatives it means that you can check the results. To display cells with negative volumes, display the result parameter in a 3D view in the Viewer, and filter out all cells with positive volumes. Map layout - Drag a surface into the Map Layout drop site to define the output map. Map output to - Select the output location for all the maps selected in the Subtypes section. Maps can be output to the following folders in the Data tree: Model QC - in the Model QC subfolder in Clipboard General 2D data - in the General 2D data folder Clipboard - in the Clipboard folder Zones - Each map is placed in the Zones folder in the Data tree, under the appropriate isochore. The grid model needs to be based on a network structural framework for this option to work. Note If Zones is selected as map output, only zone maps are created. Map increment relative to reference horizon surface - This option allows you to coarsen (or refine) the grid resolution for the output maps by selecting a value from the drop-down list. A smaller value will give more accurate maps, but a slower calculation. Variables Tab The input variables required to calculate the select volumes are entered in the Variables tab, see the following figure. Volumetrics dialog box, Variables tab Variables required to be defined will rely on options selected in the Calculations tab. Values can be given for each zone, each region, each zone and region, or as a single value for all zones and regions. For each variable to be defined, three alternative Input sources options are available: Panel - Required data must be entered directly in the dialog box. Table - Required data is taken from a table defined in the Tables main folder. The name of the table must be entered in the dialog box. Region model - Required data is taken from the region attribute table, associated with a region model selected for Region index in the General tab. Note that the Region model alternative is available only if the Each region option has been selected in the dialog box as basis for the variable specification. Fluid contact data from a region attribute table can be used in Volumetrics only if the table has been defined with a template based on standard contacts. Refer to the Working with Regions page for a general description of region models and region attribute tables. Formulas The upper section of the Variables tab lists the formulas to be used for the selected calculations. Type The options available in Variables tab depend on the input and calculations chosen in the previous tabs. To specify the variables, perform the following main steps: Select a variable class (if more than one is displayed). Select a specific variable from this class. Select the subsets (if any) for which you will give different variable values, in the Give values for section. Specify the variable value(s). The options depend on your selection in the Give values for section (step 3): For the whole grid (All zones and regions), you can enter the value as either a constant, or as a grid parameter/surface (depending on the variable). For each of the subsets (such as Each zone), you can enter constant values. In this case, you can click Fill to fill the remaining fields in the row or column with the specified value. Click Clear to set a row or column to zero. The possible selections/entries for each step are shown in the following table. Variable type Specific variables Unit measure Oil variables Gas/oil contact Depth Oil/water contact Depth Water saturation Fraction, dimensionless Bo factor Liquid formation volume factor GOR factor Gas/liquid ratio Recovery factor Fraction, dimensionless Gas variables Gas/oil contact Depth Gas/water contact Depth Water saturation Fraction, dimensionless Bg factor Gas formation volume factor LGR factor Liquid/gas ratio Recovery factor Fraction, dimensionless Formation variables Net/gross Fraction, dimensionless Porosity Fraction, dimensionless In the table, the Unit Measure refers to the Unit Set Selector , available from the Tools main menu. In this dialog, project units are defined for each parameter, through the unit measure. Note that RMS defines formation volume factors as (reservoir volume/surface volume). Variables used as input to the volume calculations can be specified in three alternative ways: Type in a constant value in the input cell. Select the Use Surface or Use Parameter check box (depending on the variable) and drag the surface or parameter into the required cell. Use a table as input - the table selected must have the same format (Columns, Rows) as specified in the Table Link section of the Volumetrics dialog box. Only tables located in the top level folder Tables in the Data tree can be used. The Tables can be found under the Library part of the Data tree, by default. Available options, and their results, are summarized in the following table. Value type Available for: Result Example Note Constant All specific variables This constant will be used in each available grid cell. A constant porosity value of 0.2  Surface The contacts  An oil/water contact The area covered by the surface should include the grid Parameter All specific variables except the contacts, but only when the option All zones and regions has been selected. Each grid cell value of the parameter will be used in the specified grid cell A porosity parameter The parameter must have the same grid definition as the current grid model grid Report File Tab In the Report file tab the output can be specified as a Report file, or a Report table data object, or both. The calculated values given in the Report file and the Report table data object are in the units taken from the Import/Export unit set. This allows you to generate the report in specified units appropriate to the intended reader or for use in an external application. Note Associated gas will have the same unit as set for STOIIP, and Associated liquid will have the same unit as set for GIIP. The Import/Export unit set is specified in the Unit Set Selector dialog box, accessed using from the RMS menu bar by selecting Tools ➥ Units (see Setting Unit Sets). Note that the volumetric units used are in the Volumetrics category, not the Reservoir engineering category (which has a separate unit for GOR, as gas and oil volumes can be in different units). In volumetrics calculations, GOR is dimensionless. Note The Report file is especially useful when your grid consists of many regions and zones. Report File The output can be specified as either Document list or Tabular (see the following two figures). The default location for the output depends on your user preferences. Volumetrics dialog box, Report file tab, for Document list layout Volumetrics dialog box, Report file tab, for Tabular layout Document list - The output is a text file. A separate file will be created for each realization. Example: If you calculated volumetrics for realizations 1 to 3 for a Document list report, and named the report files "report", RMS generates the report files report_1.txt, report_2.txt and report_3.txt Tabular - The output is presented in a table as either an Excel file (.xls or .xlsx file extensions), a comma separated file (.csv) or a text (.txt) file. A separate file will be created for each realization. If a text file is selected as the layout, each of the Main types will be presented in an individual file; select the Append additional realization results to file check box to show all realizations in the same file. Example: If you calculated volumetrics with main types Total and Oil selected for realizations 1 to 3 for a Tabular report with text file format, and named the report files "report", RMS generates the report files report_oil_1.txt, report_ oil_2.txt and report_ oil_3.txt. Note If the comma separated file (.csv) format is selected, no meta data, e.g. information about project name etc. will be given in the report file, and the delimiter used will be comma. Note that default delimiter in Excel is Semicolon, this can be changed during import. Include realization number in file name - Can be toggled off to not have the realization number added as an extension to the exported file name. This option is toggled on as default. Export parameter units to file - Select the check box to include unit information for each parameter in the report (applicable to both Document list or Tabular output). Add headers to file - Select the check box to add header to the output report file generated using the comma separated file (.csv) format. Report Output In this section the order in which the volume calculations are presented in the Report file is set. The number and form of the alternatives in the list depend on the subsets specified in the Report file tab. If Document list and a License boundary is selected as input, the License boundary will always appear first. Report Table Select the Report table check box to create a table within RMS. The results for all realizations are included in one table, along with data selection, histogram, and statistics options. This output object can be used to investigate the uncertainty in the model, and identify realizations that result in high or low volumes. Note If you select an existing Report table data object, the results can only be written to it if it has the same layout as will be generated by the current job. The Report tables can be found under Volumetrics in the Tabulated results folder in the Data tree. Click the desired table in the Data tree, and then select Volumetric table viewer... in the Task pane. Volumetric Table Viewer dialog box, Raw data tab The Volumetric Table Viewer dialog box (see the preceding figure) consists of three tabs: Data selection - In the Data selection tab what is to be displayed in the Statistics tab is set. One variable can be shown at a time, and filtered on what was used for input to the volumetric job. Statistics - The top part of the Statistics tab shows the statistics for the current volume type, for all project realizations. The P10 and P90 values are defined in relation to the standards used for reserves estimation in the oil industry. P90 reflects a low side estimate; there is 90% chance of the volumes being higher than this number. P10 represents a high side estimate; there is 10% chance of the volumes being higher than this number. Raw data - The Raw data tab presents the calculated volumetric data in a table. Note The table is generated with the appropriate number of rows and columns for the output specified in the Volumetrics job, with the assumption that the job will be run for all the project realizations. If you run the job for fewer realizations than the number set for the project, the additional rows in the table will have values set to undefined (-999). The columns that are included depend on your selection in the General and Calculations tabs of the Volumetrics job which created the table. In addition to the results by subset and calculation type, subtotals and total are given for the items and subsets. Note The TOTALS shown in the table are not the same as the Totals (sum of Oil and Gas) specified in the Volumetrics job. Note The parent job, from which the Report table originates, can be accessed by selecting the 3D volumetric table and then selecting Tasks ➥ Open parent job.... For the ease of backtracking the workflow, the created volumetric table is displayed under Workflow Output objects column of Workflows tab. Running Volumetrics When you have specified all the settings, click Save to check the job specification for errors and store the settings. Note Before running the job, check that the required Import/Export unit set has been selected, as this is used for the report output. The current setting is shown at the bottom of the window. Any requested parameters and isochore maps are created as empty data objects, if they do not already exist. If you requested a report table, this is created as a data object with the appropriate number of rows and columns, with values set as undefined (-999). To run the Volumetrics, either: Click the Run button in the Volumetrics dialog box. This runs the job for the current project realization. Or, Click Save to save the settings as a job, include the job in a workflow, and then run the workflow. This allows you to generate multiple realizations of the results. RMS calculates the volumes and displays a progress indicator pop up box. If you requested a report file, and the specified volumetrics report file already exists, a warning message is displayed asking if you want to overwrite the previous report file. If you requested a report table, and the specified table object already exists but was generated using a different job specification, a warning is displayed.
