Geolog 6.6 Determin Tutorial

Transcription

1 Geolog 6.6 Determin Tutorial

2 Contents Introduction to Geolog's Determin Tutorial Prerequisites Document Conventions Tutorial Data Determin Overview The Evaluate Module Crossplots The Xplot Window Format the X and Y Axis Format the Color Axis Color and Symbol Section Color Section Symbol Section Filter To use the Filter Tab Functions Titles Ancillaries Frequency Create and Format a Frequency Display Xplot Functions Geolog Functions User Defined Functions Function Categories CHART CURVE QUANTIFY QUALIFY CHMAP POLYGON MACRO Creating User Defined Functions POLYGON Functions Log Calculation from CHART Function CHART Functions MACRO Functions Fill Missing Values with Reconstructed Log QUALIFY Functions Geolog Determin Tutorial 01/2006 1

3 Deterministic Petrophysics Petrophysics Philosophy Definitions The Precalc Module Borehole Correct the Gamma Ray Log Borehole Correct the Density Log Borehole Correct the Neutron Log Borehole Correct the MSFL Log Borehole Correct the Dual Laterolog Parameter Picking Overview Crossplots Histograms Pickett Plots Analysis Identify Badhole Conditions Identify Coals Calculate Shale Volume Calculation of Porosity Using Sonic Log Calculation of Porosity from Density-Neutron Crossplot Water Saturation Calculation Hydrocarbon Corrected Porosity / Water Saturation Permeability Calculation Matrix Analysis Matrix Parameter Curves Used to Estimate Mineral Content Pay Sensitivity Pay Summary Multiwell Analysis Overview Select the Wells to Process Selecting Intervals to Process Multiwell Histograms Parameter Picking - Histogram Parameter Picking - Crossplot Quick Analysis (Shale Volume Calculation) Geolog Determin Tutorial 01/2006 2

4 Create a New Loglan Program Starting a New Loglan Inserting Variables Specifying Units Specifying Default Values Entering Code and Comments Geolog Determin Tutorial 01/2006 3

5 Introduction to Geolog's Determin Tutorial Welcome to the Geolog deterministic petrophysics tutorial. This tutorial will assist you in understanding how Geolog can be used as a tool for performing deterministic petrophysical well evaluations using the Determin application within Geolog. The purpose of the Determin tutorial is to provide detailed information on the tools available within Geolog for performing a deterministic formation evaluation. This tutorial will: Prerequisites Familiarize you with the Evaluate module. Familiarize you with Geolog s Xplot application. Introduce you to Geolog s Frequency application. Demonstrate the different types of Xplot functions supplied with Geolog. Familiarize you with the tools supplied in Geolog for the picking and application of petrophysical parameters. Demonstrate the workflow through a typical deterministic petrophysical evaluation using Geolog. Explain multiwell processing using Geolog s Well application. Provide an introduction to "Loglan", the Geolog programming tool. This tutorial assumes that the student has a general working knowledge of the Geolog6.6 software, and of basic petrophysics. For those without knowledge of Geolog6.6, it is strongly recommended that the Geolog6.6 Introductory tutorials be taken before commencing this tutorial. Document Conventions In this document, all INPUT to the computer is in Bold Courier New, while all OUTPUT from the computer is in Courier New, but not bold. Geolog Determin Tutorial Introduction 1

6 Tutorial Data The following additional files (files not supplied with software) are used in this tutorial: DATA: determin_master.unl REPORTS: LAYOUTS: (Copy from layout_units) determin_paysum.layout LOGLAN: SECTIONS: SPECS: PLOTS: all (in Stars project) WELLS: botein furud silt Geolog Determin Tutorial Introduction 2

7 Determin Overview The Determin application within Geolog provides advanced deterministic formation evaluation solutions for petrophysicists, geologists and engineers. Determin is a comprehensive suite of individual deterministic modules that allow the analyst to apply all the major modern petrophysical models in the traditional analysis methodology. All common techniques for shale/clay volumes, porosity, saturation and lithology determination are included. Interactive parameter picking and multi-zone/multi-well analysis provide a rapid workflow for the formation evaluation. GEOLOG Determin Tutorial Determin Overview 3

8 Step 1: The Evaluate Module Procedure The Evaluate module allows mathematical, logical or string expressions to be entered (and saved) and applied on a single or multiwell basis. These expressions can be equations utilizing a log or several logs, or can include a call to any function included with Geolog6.6 or created by the user. In this step, you will use the Evaluate module to: Generate a continuous porosity log from a simple expression involving a single density log. Invoke a Geolog6.6 supplied function (LIMIT) and apply it to a log to limit a curve. Exercise 1 This exercise demonstrates the use of the Evaluate module to generate a continuous porosity log from a simple expression involving a single density log. 1. Start Geolog and open the STARS project. 2. Start the Well application and open the BOTEIN well. 3. Select General > Evaluate to open the tp_evaluate module (see Figure 1). Figure 1: Evaluate Module Displayed in Module Launcher Window GEOLOG Determin Tutorial Step 1: The Evaluate Module 4

9 4. In the Value column, enter the following (and as shown in Figure 2): EXPRESSION: imperial: (2.65-RHO)/1.65 metric: (2650-RHO)/1650 This is the simplest form of the density porosity equation assuming RHO_MA=2.65 and RHO_FL=1.00. As a log alias list exists, the RHOB curve is used. UNITS: V/V COMMENT: Simple Density Porosity LOG_OUT: PHIT_DEN Figure 2: Values to Generate a Continuous Log of Porosity 5. Click Start to execute the module. 6. View your data by: creating a new layout inserting a scale track inserting a wireline track displaying your newly created PHIT_DEN in the wireline track setting the Right Limit to -0.5 to view the full range of data Your display should look similar to Figure 3 after applying these changes. 7. Select Well > Save. GEOLOG Determin Tutorial Step 1: The Evaluate Module 5

10 Figure 3: PHIT_DEN Log Displayed in a Layout Exercise 2 This exercise demonstrates the use of the Evaluate module to invoke a Geolog6.6 supplied function (LIMIT) and apply it to a log to limit the values. In Exercise 1 on Page 4, the given values for matrix and fluid density may result in the generation of porosity values that are negative, or greater than 100%. The LIMIT function can be used to define a valid range for a log. Values less than the minimum value will be set to the minimum value, and values greater than the maximum value will be set to the maximum value. The syntax for this function is: LIMIT(Logname, Minimum value, Maximum value) GEOLOG Determin Tutorial Step 1: The Evaluate Module 6

11 1. Display the tp_evaluate module (or select General > Evaluate, if you closed the Module Launcher window). 2. In the Value column, enter the following (and as shown in Figure 4): EXPRESSION: limit(phit_den,0,.5) UNITS: V/V TYPE: REAL COMMENT: Limited Density Porosity LOG_OUT: PHIT_DEN Figure 4: Function to Limit a Curve 3. Click Start. The data displayed in the layout is automatically updated. Expressions can be nested within Evaluate expressions, so that the two previous exercises could be carried out at the same time using a single expression of the form: limit(((2.65-rho)/1.65), 0, 0.5) GEOLOG Determin Tutorial Step 1: The Evaluate Module 7

12 Step 2: Crossplots Procedure Xplot, Geolog s crossplot application, is used for plotting logs or log expressions. It provides a variety of analytical tools to: incorporate standard contractor or user-defined curves, polygons and charts; perform regression analysis, and; calculate new logs. Xplot can be started in either Well or in Project. In this step, you will: Start the Xplot application from within Well to become familiar with the Xplot window and its components. Edit the X and Y axis of an existing crossplot. Format the Z axis. Format the display style (Symbols). Format the data display area (Ancillaries). Exercise 1 The Xplot Window In this exercise, you will change the layout you created in the previous exercise, start Geolog s Xplot application and open an existing crossplot file. 1. Within your layout view, change the displayed PHIT_DEN log to RHOB and click Apply. The defaults are updated automatically when you enter a known log name. 2. Add a second wireline track and insert the NPHI log and click OK. 3. Select Well > View > Xplot... to open the File Select dialog box. GEOLOG Determin Tutorial Step 2: Crossplots 8

13 4. Locate and open rho_nphi_gr.xplot (values of density and neutron porosity with color coding related to values of gamma ray; see Figure 5). Titles Statistics Diagram Y Axis log expression X Axis log expression Color log expression and color bar Functions Figure 5: Xplot Window Displaying RHO_NPHI_GR Xplot 5. Within the Properties dialog box, insert gr on the Z axis, and click Apply. 6. Observe the crossplot is now displayed in 3D, as shown in Figure 6. GEOLOG Determin Tutorial Step 2: Crossplots 9

14 Figure 6: Xplot Window Displaying 3D Xplot For more information refer to the Online Help - Working In 3D Xplot. 7. Remove gr from the Z Axis tab, Log Expression field, and click OK to return the crossplot to 2D. GEOLOG Determin Tutorial Step 2: Crossplots 10

15 The following table describes the components identified in Figure 5 and Figure 6. COMPONENT Titles Statistics Diagram DESCRIPTION Xplot title, well name, selected processing range/ intervals, and filters being used. Shows the number of X and Y values inside and outside the Xplot grid limits. For more information see "Ancillaries" on Page 29. X axis log expression Y axis log expression Z axis log expression (not shown) Color axis Functions The selected X, Y, and Z axis log expressions and units for each axis. For more information on the Z axis log expressions refer to the Online Help - Working in 3D Xplot. The selected Color bar, Color Expression and/or Symbol Expression (not shown) are referred to as the Color Axis. Description of an element inserted on the crossplot such as a chart, polygon or curve. Exercise 2 Format the X and Y Axis In this exercise, you will be guided through the formatting of the X axis you then follow the same procedure to format the Y axis. Formatting display areas in Geolog is performed using the Properties dialog box. To display the Properties dialog box in Xplot you can do any ONE of the following: Select Edit > Properties. Double click on a log expression. Double click on the data display area. 1. Select Edit > Properties If necessary, click on the X Axis tab. This is an example of aliasing, the Xplot layout is formatted to display the logname_cor logs but, as they do not exist, the RHOB and NPHI logs are displayed (see Figure 7). GEOLOG Determin Tutorial Step 2: Crossplots 11

16 Log name to display does not exist, so NPHI and RHOB are displayed. Figure 7: Properties Dialog Box - X and Y AXIS Tabs The X, Y and Z Axis tabs on the Properties dialog box display similar selection and formatting options. GEOLOG Determin Tutorial Step 2: Crossplots 12

17 The following table explains each of the fields on the X, Y and Z axis tabs of the Properties dialog box: SECTION FIELD/BUTTON DESCRIPTION Log Log Expression A log name or expression that evaluates to a numerical result. An X and Y value must be specified to display data (see Figure 5), and a Z value must be specified for a 3D display (see Figure 6). If changing an existing log, the Default units are automatically displayed. This replaces displayed Units, Left/Right and Scale values with the default values specified in the loginfo.loginfo file found in the unit_type/specs directory for your environment. If you change any of the displayed Units, Left/Right and Scale values click on the Defaults button to redisplay the default values. Units Limits (Left / Right Limit - X axis) (Bottom / Top Limit - Y axis) (Lower / Upper Limit - Z axis) Default units are displayed for a log entered in the Log Expression field. Limit values for each axis are displayed according to defaults for the Units selected. These defaults are determined by Left and Right limit values in a loginfo file. For the Y axis, left and right limits are translated to bottom and top, respectively. For the Z axis, left and right limits are translated to lower and upper, respectively. Scale Control Sampling Use the Swap Limits these two fields. The scale is represented by grid lines. icon to quickly swap the values in Note: The Limits specified must be greater than 0 for all but Linear. The sampling rate of one axis (X, Y or Z) can be used to determine displayed log values of the other axes by interpolation. Whichever axis has this toggled ON indicates that axis controls the sampling. GEOLOG Determin Tutorial Step 2: Crossplots 13

18 SECTION FIELD/BUTTON DESCRIPTION Grid Style Intervals Appearance Standard - LINEAR scale only Enter a single value for Fine and/or Coarse Grid Intervals for a Standard grid to display linear scale grids. The Grid is calculated using the Left and Right Limits, and the Fine and Coarse Grid Intervals (Left - Right / Grid Interval value; e.g., if the Left limit is 0 and the Right limit is 200, a Coarse Grid Interval of 10 will display grids at 20, 40, ). Variable - ALL scales Enter multiple values for Fine and/or Coarse Grid Intervals for a Variable grid to display grids according to the Fine and Coarse grid values entered. Enter values separated by spaces where grid lines are to appear (e.g , etc.). To quickly remove the grids from the view, toggle View > Grids. To set the appearance of grids, click in an Appearance field to display the Appearance Palette and set the color, line style and width, and text. Text denoting grid positions appears at both ends of the grid lines. As a simple exercise in using the X and Y Axis tabs, do the following: 3. For the X axis, change the Right limit to 0.5 and the Coarse grid lines to Magenta. 4. For the Y axis, change the Bottom limit to 3.2 (3200) and the Coarse grid lines to Blue. 5. Click Apply. Exercise 3 Format the Color Axis Colors, expressions, symbols, and/or text (all referred to as a "Color axis") can be applied to data displayed on a crossplot. 1. Select the Color Tab. GEOLOG Determin Tutorial Step 2: Crossplots 14

19 Figure 8: Properties Dialog Box - Color Axis Tab Color and Symbol Section The following table describes the Color and Symbol section components of the Color tab as shown in Figure 8: FIELD/BUTTON Style DESCRIPTION Determines the style of the displayed symbols. Note: Not available when viewing 3D crossplots. Marker - The marker selected in the Appearance field is shown at the center of each grid cell. Solid Fill - Each grid cell is shown as a filled rectangle. When specifying a Symbol Expression, these styles only apply to the display of indeterminate results. Note: Solid Fill is automatically set when using Accumulation settings on the Filter tab, and automatically set back to Marker when Accumulation is set to None. GEOLOG Determin Tutorial Step 2: Crossplots 15

20 FIELD/BUTTON DESCRIPTION Appearance Connection The Appearance settings (attributes) selected in this field apply to both the Color and the Symbol sections on the Color tab. Click in the Appearance field to display the Appearance Palette to format the style, and color of symbols and lines. Specifies the line style in the Appearance field. However, it does not apply to accumulated values. None - Values are not connected. Line - Values are connected with a straight line. Spline - Values are connected with a smooth curve. Note: Line styles are not available when in 3D mode; and should not be used when plotting arrays on X or Y axes. Show Missing Values Toggled OFF - missing Color or Symbol values are not processed. Toggled ON - missing Color or Symbol values are processed and displayed using the settings specified in the Appearance field. 2. With the Style set to Marker, using the Appearance Palette set the color to Blue and the Marker to Ball. 3. In the Color section remove the Expression GR_COR and click Apply. 4. Observe the changes made to the crossplot. 5. Change the Style to Solid Fill and click Apply. 6. Observe the crossplot. "Ball" is ignored and filled rectangles for each grid cell containing X/Y values are displayed. GEOLOG Determin Tutorial Step 2: Crossplots 16

21 Crossplot with the marker style Crossplot with the solid fill style Figure 9: Crossplots Showing Different Color Styles Color Section The following table describes the Color section components of the Color tab as shown in Figure 8: 1. Change the Style back to Marker and set the Expression to rainbow(gr,20,150) In the Expression field, Geolog converts lowercase to uppercase when you click Apply. 2. Click Apply. The Color Bar specified (i.e., gr.qualify) is ignored and the values are displayed according to the expression. Note the expression displayed beneath the color bar on the crossplot. See Figure 10. GEOLOG Determin Tutorial Step 2: Crossplots 17

22 FIELD/BUTTON Expression Display Value DESCRIPTION A log name or an expression determines the color of the data values. RAINBOW expression A rainbow expression can be used as an alternative to selecting an Expression and Color Bar. For example, for the expression syntax RAINBOW(GR,0,200), GR is a log name and the values represent the range to be displayed. Values within the range are displayed according to the color spectrum between blue and red. WELL_NO expression When processing multiple wells, remove the Color Bar and click on the Dropdown List button to select WELL_NO to have each well display in a default color assigned from the Appearance palette. Alternatively, a Color Bar may be specified to select specific colors from the Color Bar for each well (see WELL_NO as a Color Expression for an example). Note: When using WELL_NO, a Color Bar is not displayed, as the well names in the legend identify the wells and colors. INTERVAL_NO expression When processing multiple intervals, remove the Color Bar and click the Dropdown List button to select INTERVAL_NO to have each interval specified for processing display in a default color assigned from the Appearance palette. This enables you to select the required set of values to display the data: Minimum, Maximum, Average, or Frequency. GEOLOG Determin Tutorial Step 2: Crossplots 18

23 FIELD/BUTTON Color Bar DESCRIPTION If no Color Bar is selected, the data point colors are determined directly by the Color Expression. If the Color Expression evaluates to a string (e.g. "GREEN"), then that color will be used. If the Color Expression evaluates to a whole number, (e.g. WELL_NO), then a color will be automatically selected from the Appearance Palette to represent each number. You can enter/select a qualify function which determines the color representation of expression values using one of the following: The Dropdown List button to select from existing Qualify functions. The default reserved qualify functions Rainbow and Grayscale can be used to automatically create a color bar if an appropriate color bar does not exist. When selected, all displayed data is encompassed within the color (or grayscale) range. For example, if GR is entered and the displayed data is within the range of GR values 21 and 176, the Color Bar encompasses these values within the rainbow or grayscale color range of 20 to 180. The File Select icon to open the File Select Dialog Box to select the qualify function from another location. Frequency Bar The Colormap icon to edit/create a color bar. These colormaps can be changed, or new ones created, when required. Colormaps are located in, and saved to, the /functions directory with an extension of.qualify. This is only available when the Display Value is set to Frequency. The required qualify function is selected to display the data frequencies. If the default reserved qualify functions Rainbow or Grayscale Color Bar is selected, a color bar is automatically created to encompass the range of frequencies for the displayed data. GEOLOG Determin Tutorial Step 2: Crossplots 19

24 Figure 10: Using Rainbow Expression to Identify Formation Colors with Solid Color 3. Change the expression back to GR_COR and click Apply. Colormaps Colormaps are used in Geolog for various functions such as displaying array data image logs (representing vertical and horizontal variation in formation properties), and representing the Color axis on crossplots. These colormaps can be changed, or new ones created, as required. Colormaps are QUALIFY functions, and are located in, and saved to, the functions directory with an extension of.qualify. 4. Click on the Colormap icon to open the colormap currently specified in the Color Bar field (see Figure 11). GEOLOG Determin Tutorial Step 2: Crossplots 20

25 Currently open colormap Color cells Name Figure 11: Colormap Dialog Box Interactive visual guide when changing Function and Direction of colormap indicates the colormap currently displayed. Check this name is the same as the color bar title displayed in the crossplot to ensure you are saving changes to the correct colormap, as it is possible to display the properties of another colormap within the currently open colormap (using File > Import). If a colormap has not been specified before clicking on the Colormap icon, or when you select File > New, a default "rainbow" style colormap titled "no_name" is displayed in Manual mode. To create a new map, you can change this rainbow style, or open an existing colormap (File > Open) and make the required changes. 5. Click the File>> button and select Import... to import the properties of another colormap. 6. Locate and select fms.qualify. NOTE the name displayed in the Name field and the crossplot color bar title are different. 7. Click the File>> button and select New to start a new colormap, and Discard the changes. GEOLOG Determin Tutorial Step 2: Crossplots 21

26 8. Click the File>> button and select Size... to open the Colormap size dialog box. 9. Specify a range of 0 to 200, and 10 intervals. 10. Click OK. 11. Click the Tools>> button. Note all the options are grayed out, this is because there are no color cells selected. 12. Click and drag across the color cells to select them (each selected cell is outlined in red). Selected color cells 13. Click the Tools>> button and select Grayscale. 14. Change the colors back to Rainbow. 15. Select the first (leftmost) cell. 16. Change the Cell To value to 25 and click Apply. 17. Select the resized cell. 18. Click on the Appearance palette icon and change the color of the cell. 19. Select all the color cells. GEOLOG Determin Tutorial Step 2: Crossplots 22

27 20. Click on the Tools>> button and select Interpolate. 21. Click on the Function field Dropdown List button and select an option. 22. Adjust the red control points. Geolog dynamically displays the changes in the Function Colormap area. 23. Select the Reverse direction. 24. Click on the File>> button and save your colormap as mycolors. (Enter the name at the end of the path in the Selection field; if a /functions directory does not exist for your project, Geolog will create one now.) 25. Close the Colormap dialog box. 26. On the Color tab of the Properties dialog box, click the Color Bar File Select icon to locate and select your new colormap. 27. Click Apply. See the Using Geolog online help for detailed information on colormaps. GEOLOG Determin Tutorial Step 2: Crossplots 23

28 Symbol Section You use the Symbol section of the Color tab to select the symbol used to display values. The following table explains the fields in the Symbol section: FIELD / BUTTON Expression DESCRIPTION Note: Not available when viewing a 3D crossplot. Style The Log Select icon enables you to select the required log, or enter a log name or expression. When using expressions, ensure the appropriate Style is selected (e.g. toggle on "Marker" if SYMBOL is entered to display the symbol specified in the well header constants, "Fill" if a lithology log is selected, "Text" if WELL_NO is selected). Ensure a Color Expression has been selected and then click on the Dropdown List button to select one of four special Symbol Expressions: MINIMUM, MAXIMUM, AVERAGE or FREQUENCY to provide direct access to the statistics accumulated for each grid cell for the Color Expression. These special expressions are usually only meaningful when the Symbol Style is set to Text. If the expression WELL_NO is used in Multiwell Processing, values are identified by a number for each well selected for processing. The style of displayed symbols. Marker: If the Symbol Expression evaluates to a string (e.g. "BALL"), then a marker with that name will be used. If the Symbol Expression evaluates to a whole number (e.g. WELL_NO), then a marker will be automatically selected from the Appearance palette to represent each number. If the marker cannot be found, an error message is generated and, in Multiwell Processing, the marker is not displayed in the Well Legend. Fill: If the Symbol Expression evaluates to a string (e.g. "SS") then a fill pattern with that name will be used. If the Symbol Expression evaluates to a whole number (e.g. WELL_NO) then a fill pattern will be automatically selected from the Appearance palette to represent each number. If the fill cannot be found, an error message is generated and, in Multiwell Processing, the fill is not displayed in the Well Legend. Text: Symbol Expression values are displayed as text (e.g. select a depth log as the expression to show the depth for displayed values). GEOLOG Determin Tutorial Step 2: Crossplots 24

29 Exercise 4 Filter The Filter tab in the Properties dialog box is used to: define a filter to display a range of values (e.g. depth range) define frequency accumulation to aggregate multiple values to one point adjust a 3D display To use the Filter Tab 1. Click the Filter tab in the Properties dialog box. Figure 12: Properties Dialog Box - Filter Tab GEOLOG Determin Tutorial Step 2: Crossplots 25