Petrel Notes April 17, 2023

Contents:

Tip: Use Copy–Paste and document search function to find description/workflow

Change color for active interpretation:

Well Section Template Add log to existing track in:

Well Section Template Seismic Gain:

Remove structural dip from wellbore seismic panel in Well Section Template:

Well Section Template change color bar (Template) of synthetic and seismic panels:

Display well tops in a Seismic Well Tie - Wavelet Extraction Window:

Display synthetic on well path in 3D window:

Delete arbitrary line anchor points made while building a line:

Arbitrary lines -- Blue vs Red Icons:

Rescale Seismic in Interpretation Window:

Load Well Picks by Hand (Manually):

A surface picked in time and converted to depth is grayed out and won’t display:

Switch between 3D surveys in an Interpretation Window – a 2D window open next to it is a plus:

Create a Random line across 2 surveys:

General Sluggish Project Operation:

Append (or butt join) two polylines:

Gridding with single line fault polygons:

Poor graphics quality in a Geobody Probe:Copy horizon interpretation made on one survey to another survey:

Copy and pasting petrel spreadsheet into Excel leaves values less than 1 as 0:

Parent/Child Relationships:

Display seismic from one survey on an inline, crossline or random line picked from another survey:

Sluggish activity: Takes prohibitively long to pan through seismic using the Manipulate Plane function or the page up/down keys: I and J axes:

Sluggish activity when working with interpretation converted from a surface:

Extract Well Tops (Take Point) at a Surface:

Seismic Well Tie, Synthetics (Stretch and Squeeze):

Exclude some well tops in a well tie (flexing) operation:

Project Units Inconsistent with Projection:

Domain Convert Seismic Volume Fails:

Domain Convert Seismic Volume Fails:

Can’t Convert XY Feet to Meters on SEGY load:

Convert a surface to interpretation in Blueback Tools:

Import Grid from XYZ ascii:

Process window won’t open:

How to make autopicked interpretation stop at faults:

Show fault interpretation as a trace only in 3D window:

Hide or show zones in well tops folder:

Cursor tracking doesn’t work:

Turn off / on one or more well’s tops / markers / picks that they won’t be used in the Make / Edit Surface well adjustment process:

Calculate area inside a polygon:Can’t move seismic lines on basemap with Manipulate Plane function:

Create a polygon line at the intersection of two surfaces:

Append polygons:

Smooth seismic interpretation picks:

Drape an Image (JPG) onto a surface:

Build a depth conversion (velocity) model from a seismic velocity model, cube, or field that can be loaded as a seismic volume:

Compute or Extract an Amplitude or Other Attribute at a surface:

Extract a velocity attribute at a surface:

Set Color Bar (Template) to display Z/Time values in 2D Window:

Edit the Seismic Geometry Display (Inlines/Xlines and annotation) in a 2D/3D Window etc:

Displaying the Proper Template or Color bar in a 2D Window (To become more intuitive in version 2012):

Displaying Seismic From Two Surveys Simultaneously or One as a Semitransparent Backdrop to Another:

Unable to overwrite picks at line intersections in a 3D window:

Display Time Seismic on an Arbline Originally Picked in Depth or Vice Versa:

Horizon Auto tracking on Non-Zero Centric Data:

Make/Edit Surface Process Settings Window Opens Off Desktop: Can’t Find Make/Edit Surface Settings Window:

Tip: Interpretation Window DVD player style tool bar constantly shifts window when window is activated:

Logging into HP Remote Graphics:

Volumetrics Workflow:

Calculate a difference volume

Display Multiple inlines in a 3D windowTip: Lose your light source? On the dark side of the seismic line?

Blueback Tools Seismic Spectrum Probe:

Create a Horizon or Box Probe

RGB Blending

Creating a time shift RGB Blend

Editing the Color bar or Template

Tip: Ctrl P to unpick a selection made in select/pick mode.

Delete Autopicked Interpretation or Any Other Pick Type

Make/Edit Surface using Additional Inputs Tab

Make a 3D GRV Model Volume for a Horizon Top and Base Horizontally Offset From Each Other Such As Along an Inclined Fault Plane for Use in the Make Simple Grid Process for Reserves Calculations.

Well Section Curve Header Has Wrong Units or Decimal Precision

Calculate Autopicked Amplitude Area or Create a Quick Look Surface

Expand or Shrink a Surface (Grid) Larger or Smaller Than Its Containing Polygon.

Append / Connect / Join Two Faults:

Change Color Bar Display

Map Window Object Layering and Ticks

Inline Crossline Readouts at Cursor

Export well logs to LAS

Extract Well Picks From Surfaces

Add / Edit a Well KB Elevation

Fault Throw Analysis

Combine Checkshots into One Global Checkshot for All Wells.

Build a 3D Grid for Depth Conversion Using CheckshotsUp-Scale Seismic into a 3D Grid

Create a Custom Contour or Contact Contour

Create a Net to Gross or Percent Grid from an Attribute.

Prepare a Fault for Fault Modeling.

Prepare a Surface for a 3D Geologic Model (Geomodel)

Build a 3D Geologic Model (Geomodel)

Condition and Smooth a Hand Drawn Polygon

Fault Modeling - Digitizing a Pillar Fault using an Existing Fault

Create a Fence Diagram of Model Properties

Build a Model Property Dividing the Entire Property Region into Two Regions Separated by a Fault Surface Grid

Create a Geomodel Workflow

A Geomodel Workflow Example

Insert a General Intersection into a model

Build Gas/Water, Oil/Water or Gas/Oil/Water Contacts Model Property

Compute GRV Surfaces From Top and Base Horizontally Offset as by Faults or Diapirs

Edit a Polygon Using the Keyboard

Reserves Calculation Error after Applying Formation Volume Factor (FVF)

Can’t Delete Seismic Folder

Extract a velocity log for all wells from a velocity volume.

Change color for active interpretation:

Seismic Interpretation Process Settings > Interpretation > Active Horizon

Well Section Template Add log to existing track in:

In the Global Well Logs folder RMB on a log and choose Add to Template.

Well Section Template Seismic Gain:

Set the gain of extracted seismic using the Operations tab-Amplitude tab at the source seismic settings. Lower the absolute values. Change its template in the Synthetics folder under Global Well Logs.

Remove structural dip from wellbore seismic panel in Well Section Template:

The well’s position relative to the sample seismic extracted along its path is at the center of the panel. In steep dip reflections from a Radial Extraction along the well’s path will be high on one end and low on the other making it hard to detail a tie. An Orbital extraction with a radius of 1 will give the panel the appearance of flatness. To redo open the settings for the extracted seismic under the Synthetics folder under the Global Well Logs folder in the Wells folder and choose the Well Seismic tab. Set the radio button to Orbital and Radius to 1 and Apply-Cancel or OK.

Well Section Template change color bar (Template) of synthetic and seismic panels:

In the Global Well Logs folder – Synthetics folder – Synthetic/seismic settings – Info tab.

Vertically Align Wells, Set Well Spacing, Setup Printing, etc. in a Well Section Window:

Open the Well Section Window settings under the windows tree.

Display well tops in a Seismic Well Tie - Wavelet Extraction Window:

Prior to opening a Wavelet Extraction Window make a well tops folder active.

Tip: all tops are displayed. To display only some tops you must make a well tops folder that has only those tops.

Display synthetic on well path in 3D window:

Check the box next to the synthetic in the Synthetics folder under the Global Well Logs folder in the Wells folder.

Tip: If you can’t see the synthetic note that it is displayed in 2D ro rotate the 3D display to see it. Also, open the synthetic’s setting and under the Style tab turn on Wiggles and experiment with the wiggle options there.

Delete arbitrary line anchor points made while building a line:

Use the delete key.

Arbitrary lines -- Blue vs Red Icons:

Other than the way they function as detailed in hand written notes, Blue lines are stored under the seismic folder active at creation. Red lines are stored separately from the active seismic at the same tree level as the seismic. Red lines are to connect between different surveys. Other differences are: Arblines generated using the blue icon are polygonal lines meaning they can be edited like any other polygon in the Make/Edit Polygon process. To do so, with the Make Edit Polygon and 2D Window (basemap) active expand the tree under the General Intersection (Arbline) and put a check in the box corresponding to the arbitrary polygon. Then edit as any other polygon.

Rescale Seismic in Interpretation Window:

Use the shift key and grab the edge of the horizontal or vertical scroll/slide bar and slide accordingly.

Load Well Picks by Hand (Manually):

Insert new well tops from the main menu Insert tab. RMB on the Stratigraphy folder and Insert Zone/Horizon. Rename it in its settings or as you would any file name using a slow double click or the F2 key. Open a new Well Section Window

and select a well from the wells folder. Select logs to display from the Global Well Logs folder. Scroll up or down in the window to find the horizontal line in the depth column separated by grey and white. Grab that line to expand the log. Find and click the icon for Create/Edit Well Tops (hot key E) and make active (bold font) by clicking on it the pick to which you want to assign a depth. In the log column of the well section window find the depth, either MD or SSTVD and click. The top should appear on the well section. Repeat.

Also, see Make/Edit Well Tops under Stratigraphy in the Processes tree.

A surface picked in time and converted to depth is grayed out and won’t display:

The velocity model associated with the depth conversion is not active (bold font) in the models tab of the project tree.

Switch between 3D surveys in an Interpretation Window – a 2D window open next to it is a plus:

With the Interpretation Window active expand the seismic tree and the survey trees of the surveys between which you will be switching. Check the inlines or crosslines to switch from one to the next across the surveys. With the 2D window active (click on its window tab or on its name in the tree) check box next to the surveys you will be using i.e. check the box next to the survey one branch up from the lines. This will overlay the surveys’ grids in the 2D window. The line in the Interpretation Window will illuminate fat and yellow. Again, with the 2D window active, click the Manipulate Plane icon and LMB grab the fat yellow line to slide the line in the Interpretation Window to a new location.

Tips:

If for some reason you can’t grab and slide a line check that the Seismic Interpretation process is active by clicking on it (bold font) and/or try moving it with the page-up or page-down keys or the DVD buttons. Then try the grab-and-slide technique again.

You can open random lines in the interpretation window by checking the box nest to them. Or create a random line in the 2D window to be displayed in the interpretation window (see next entry).

Note:

You will also be able to slide the lines in the 2D window that are not active (fat and yellow).

Create a Random line across 2 surveys:

From an active 2D window as described above make the first survey active (Bold Font) by clicking on it once in the tree one branch above the lines. Select the Draw Arbitrary Composite Sections icon (Icon w/ red random line in it; hotkey W) and start picking the arbline in the active survey area (Use the delete key to undo the last picked anchor point). When over the next survey area and ready to switch to the next survey make it active and continue picking. Repeat as necessary. Double click to end the line and it will appear in the Interpretation Window if it is open. If it is not, open it and check the box next to the composite line you created in the main tree found under the Seismic folder in a subfolder called Composite Folder. You can rename the folder and line if you want.

General Sluggish Project Operation:

Close windows you will not be using for a while and open new ones when you need them again. Windows that have been open for a while can become corrupted and cause hanging or slow operation.

Append (or butt join) two polylines:

If the two polygons are in separate polygon files they first have to be combined into one. Do this by opening the settings of one and choosing Operations-Polygon operations-Append polygons. With “Make/edit Polygons” process and the Polygon file active (Bold Font) click the “Select and edit/add points” icon and click the end anchor point of the first polyline. With the shift key click the end anchor point of the polyline to be joined. This should render the “Connect polygon” icon active. Click it to join.

Tip: If the “Connect polygon” icon is not activated by this process look that you have not picked the ending anchor point for one or both the lines. In some instances two anchor points could be overlying one another. Zoom in.

Gridding with single line fault polygons:

Grid faults as surfaces (you can even merge to faults into one surface using the Operations-Eliminate and Surface-surface functions).

Display fault surfaces on interpretation window while detailing horizon seismic picks on upthrown and downthrown sides of faults surfaces. For thrusted surfaces map the hanging wall separately as two Z’s can’t occupy the same XY.

Grid the surface(s) to satisfaction without faults. Tip: use a boundary polygon.

Open the settings for each grid (surface) and choose Operations, expand Convert points/polygons/surfaces and select Create intersection with surface. Do this with each of your fault surfaces. Tip: if your fault forms a closed polygon you may want to eliminate the surface inside or outside of it.

The polygon points may not be closed. Open the polygons or polylines, select them with the paintbrush select tool and close (connect) them. Optional: You may also want to combine them into one polygon file. See “Append polygons” above.

Copy/Paste the intersection polyline (append it to its parent if necessary as described above) and offset it with the Select and Edit Line icon. Connect the ends to form a fault gap polygon.

If interpretation is two or more surfaces repeat above with the others.

Regrid the interpretation using the fault polygons or eliminate inside/outside the closed polygons under the surface settings calculations tab. Reminder: you may want to turn off gridding inside polygons in the Make/edit surface algorithm tab.

Poor graphics quality in a Geobody Probe:

There are two settings regarding graphics memory. One is hardware (physical memory on the computer’s graphics card) and the other is how much of that memory the Geobody Interpretation process is allowed to use.

Under the main menu Tools – System Settings – Seismic tab – Graphics Card Memory should be set to the amount of the memory on the computer’s graphics card.

Under the Processes tab of Petrel’s main file tree expand the Geophysics folder and double click on the Geobody Interpretation process or RMB on it and open the settings option. Under the settings tab set the Render Cash Size to some 1/3 or 3/4 of the available graphics card memory. Do not set it to the same value as you need some graphics memory for all other video displaying.

Copy horizon interpretation made on one survey to another survey:

Make a copy of the interpretation before you begin by using ctrl-C and then ctrl-V. Make the target survey active by clicking on it and making its font bold (the survey is the folder one branch below the main seismic folder). RMB on the existing interpretation root folder and select Insert Interpretation for Active Survey. Your active survey should appear with the selection in parenthesis to insure you have the right one active. In the tree under the interpretation there should appear a new empty survey selection. At this point you can start interpreting the horizon on the new survey, but it does not have any interpretation made on the original survey. To copy existing interpretation to the newly created survey RMB on the original survey and choose Copy 3D interpretation grid (data only) then RMB on the new survey and click Paste 3D interpretation grid.

Tip: The above interpretation copy/paste operation has failed at times and may have some survey geometry requirements. If it fails try this: Open the new interpretation’s settings and go to the operations tab. Choose Surface to Surface operations and A Union B, Keep B. Insert in the box next to the blue arrow the interpretation with picks by click and drag or highlight it and clicking the blue arrow. Click Run.

Blueblack tool box has a function under Object Operations – Copy interpretation that will copy the interpretation from another survey to the new survey so you can continue interpreting on the new one. Select your source and target from under the tree of the interpretation where your newly created 3D interpretation grid is found.

Copy and pasting petrel spreadsheet into Excel leaves values less than 1 as 0:

If the template for a well data such as porosity and Sw is set to General or otherwise the wrong template leaves the values in the spreadsheet for that data as 0, only revealing its true value when the cell is selected with the mouse. Copying the cell to an excel spreadsheet only copies the whole number or zero portion, dropping the values right of the decimal place.

Change the settings for the item to the correct template and the format in the spreadsheet for that column will reveal the correct decimal value.

Parent/Child Relationships:

With 3D volume and horizon active click the Paint Brush Select icon and one of the parent/child relationship icons in the tool bar. Paint or click on the interpretation. The result shows origins of autopicked interpretation.

Display seismic from one survey on an inline, crossline or random line picked from another survey:

On any seismic line displayed in an Interpretation Window you can drop the seismic from another survey by putting a check in the box next to that survey one branch up from that survey’s inlines, Xlines or slices. If the surveys have inlines and Xlines in different orientations it will effectively create a random line of the second in the line direction of the first.

Sluggish activity: Takes prohibitively long to pan through seismic using the Manipulate Plane function or the page up/down keys: I and J axes:

Try turning off all surfaces in all windows (even windows in the Windows tab that may not be open at the moment). If the problem goes away then in each of the surfaces that you turned off check in their settings under the statistics tab that in the Description of the surface its geometry is not being described as in the I and J direction. This may occur (but not exclusively) when converting a surface attribute to a surface.

Resample the surface in the Make/Edit Surface process by using the offending surface as input and any boundaries you choose as constraints. Pick the geometry from a non-offending surface or a seismic volume. Set the grid increment. Choose the “Surface Resampling” algorithm and OK.

Check the surface in a window and that its statistics are described in x and y and not in Number of 2D Nodes I and J Direction and that seismic manipulation performance is acceptable with the surface turned on in a interpretation or seismic window. Delete the offensive surface and take a moment to reorganize your file tree.

Check for other similarly offending surfaces and fix accordingly.

Tip:

The icons at the top of the main Petrel window change as you select different processes.

Sluggish activity when working with interpretation converted from a surface:

If you are working with multiple surveys the conversion of a surface to interpretation outside of the Blueback tools will make interpretation for all the valid surveys in the project. Expand the tree under the converted interpretation and delete the surveys not desired.

Extract Well Tops (Take Point) at a Surface:

1. Open the Wells folder Settings window and the Report Tab.

2. TIP: To Keep the results separate from existing tops Create a new Well Tops folder using the Insert option off the main Petrel menu.

3. Make the new Well Tops folder active (bold font) by clicking once on it.

4. Check the box next to “Make Well Report” and “Iconize Points As” and select “Horizon in Active Well Tops” button”.

5. From the Surfaces folder in the Input window select the surfaces on which you want to extract the tops. Use the Ctrl Key and RMB for more than one.

6. Back in the Wells folder Settings click the “Append Selected Item” icon. This should place the surfaces from step 5 in the list at right.

7. Click run. A report of the results will appear and the wells tops folder will populate w/ tops.

Seismic Well Tie, Synthetics (Stretch and Squeeze):

For help search on “Time Shift and Manual Adjustment”.

The final synthetic trace made in the Seismic well tie process can be bulk shifted or stretched and squeezed to align it to the real seismic data. The alignment points can be set randomly on any strong event that needs to be adjusted and any updates are applied as soon as they are needed.

The adjusted synthetic trace can be output back to the Input pane of Petrel with a different name than the original unadjusted trace for comparison and use.

Parent topic: Synthetic SeismogramsTime shift and manual adjustment workflowThe Wavelet extraction window is used for manual adjustment. The manually adjusted synthetic trace is updated interactively and is saved back to the Input pane for further use.

Open the Wavelet extraction window to perform this workflow. You can either use the icon from the Function bar, access it from the Seismic well tie process dialog, or from the Windows pane if Petrel has not been closed since the wavelet extraction workflow was done.

Note that the windows used in the Seismic well tie process are not accessible after Petrel is closed down. Make sure to finalize the workflow and output all needed results back to the Input pane before closing down Petrel.

Variable time shift alignment

Controlling the variable time shift alignment is done from the Wavelet extraction variables and settings dialog, Time shift tab.

If you select the Move and add alignment points button, any point can be set on the seismic (preferably on a strong event/marker) and adjusted to the corresponding event on the synthetic trace.

The difference in time picks can be collapsed by selecting the Use variable time shift button.

Notes by JAH:

The panel provided for the stretch and squeeze correlation doesn’t offer many options. As a supplement and alternate viewpoint for making the visual correlations use a Well Section window. Below is a suggested semi-detailed workflow.

Open the well in the Well Section display and turn on any logs you may want to use as visual aids. Some of these may be DT, RHOB, a Vp curve and the well’s check shot.

Open the Synthetics process and create a synthetic for one or all your wells. You may also have to create a wavelet. In this process under the last tab extract seismic along the well paths. Set up the well section template with the synthetic and the wellbore extracted seismic in two panels side by side. Set the amplitude gain for the synthetic/seismic panels in the Template Settings, Seismic Log, Seismic Style tab, Scale or

the source seismic’s Settings, Operations tab, Amplitude tab. Save this as a seismic template. Find these under the Global Well Logs folder in the Synthetics folder. Make sure there is a time as well as depth column.

RMB on your well or DT/RHOB log under it and choose to create a Log Set from the drop down menu. Open the Log Set’s settings and add sonic and density logs.

Open the Seismic Well Tie process. Leave all the windows that pop up open (you will have to close and reopen some to show newly created data/logs). Browse the tabs in the main window. Save project often.

The first option is to calibrate the Sonic. This is optional. You can close this windows and its dialog box when done. You create a new sonic that will tie the well to time seismic same as the checkshot (it’s calibrated to the checkshot). If the checkshot doesn’t tie the well make a stretch and squeeze tie and re-calibrate the sonic. Knee Picking is followed by Output.

Click on the Wavelet Extraction tab in the Well Seismic Tie process and the New wavelet extraction window at the bottom. Follow the instructions. After you bring in the data you will see there is no synthetic. In the settings dialog box look at all the tabs. The input tabs are mostly populated. The output tabs are for saving results. The position tab is important for directional holes. Consider checking the two boxes under Verticalisation when tying a directional hole. Mouse over the blue ? icon for more info.

Create an artificial wavelet by clicking the Wavelet Builder Tab in the Seismic Well Tie process instructional box. The artificial wavelet must be the same sample rate as the seismic you dragged to the display, usually 4 ms. You can check that in the source seismic’s Settings, Geometry tab.

Drag the newly created saved wavelet from the Input window to the blue box labeled Pilot Wavelet in the Input 1 tab of the Wavelet Extraction Variables and Settings dialog box. A Pilot Wavelet Display box will open.

Or, Extract a wavelet. Two boxes open showing details of the wavelet. Click on the Tools button at bottom of the Extracted Wavelet display. With these tools you can alter the wavelet’s appearance to improve your ability to tie the synthetic. Updates are immediate. Note: The character of an extracted wavelet depends on the initial tie.

If you close the Wavelet Extraction Variables and Settings window you can reopen it by RMB selecting Variables and Settings. RMB in the seismic/synthetic background gives you some other options. Select Split seismic display attributes. Here you can set the display of the synthetic/seismic panel.

Before you do any stretching or squeezing you may want to anchor you synthetic where you think the tie is right. This may only be at the water bottom. In the settings select the Time Shift tab and look closely at all the options. Also, check the starting tie against the tie in the well section window. You may see things differently. The default checkshot should be in use in both Well Seismic Tie and Well Section. If in doubt check this in the well’s Settings, Time tab and the Input 2 tab of the Wavelet Extraction Variables and Settings window.

If the synthetic and the sample data in the synthetic tie window (Wavelet Extraction window) is not amplitude balanced change the Normalization type under that tab in the Split Seismic Display Attributes dialog box.

If there is a tie you want to keep or make in the Well Section window put your mouse over that spot on the seismic panel and read the time. If it’s a tie you want to make, mouse over the synthetic panel and note the offset time. In the Well Extraction window and with the Time Shift tab open in the settings box and the Move and Add Alignment Points radio button on, click once in the synthetic tie panel at the first desire time as indicated on the digital display at the bottom of the window. A red line will appear labeled “A” (if it’s the first one). If you do nothing more, this will anchor the tie at that point. If you what to change the tie then click and hold the red line in the synthetic panel and drag it to the offset time you noted earlier. Similarly, create any other tie points you desire. To make the shift check the Use Variable Time Shift check box. To see your result without the red time shift lines click on the synthetic tab. When you think you have a tie extract a wavelet. It may look better but you also may have to retie with it.

If this tie is likeable save a syntied checkshot under the Output 2 tab of the settings box Time/Depth Curve. Once saved open the settings for the well and go to the Time tab. The saved checkshot should be in the list of available time/depth relationships there. Check Override global settings and put a checkbox next to your syntied checkshot. Uncheck all other boxes including Shared checkshot (if checked) and click Run.

If you have set the Time/Depth blue box under the Input 2 tab of the Wavelet Extraction settings box to Use preferred well time/depth then every time you change the preferred checkshot in the well’s settings, Time tab, the checkshot will automatically update in the Well Extraction window.

Exclude some well tops in a well tie (flexing) operation:

Open the well tops spreadsheet using the RMB on the tops folder. Expand the spreadsheet to see more cells. Uncheck the check boxes in columns “Use by Depth Conversion” and “Used by Geomodel”. It may only be necessary to uncheck the first.

Insure the tops don’t show up in the well tie report and didn’t adjust to tie the wells.

Project Units Inconsistent with Projection:

If you open an early vintage project and get the message the project’s units are not correct you can accept to change the units but be aware the numbers will still be the same e.g. if an old project created projectionless in an early version of Petrel in XYZ ft-ft-ft is opened in Petrel 2011 and a UTM projection is applied it will object to the XY units in feet and ask if it can change them to meters. Accepting will not convert but simply change the units to meters – the numbers will be the same.

Domain Convert Seismic Volume Fails:

Domain conversion of a seismic volume fails because software can’t write to the folder necessary to save. Problem turns out to be the seismic is in a non-standard seismic folder. Create a new seismic folder and move the data to it. Repeat the process from the new folder.

Can’t Convert XY Feet to Meters on SEGY load:

Segy data is in XY feet but apparently has an EBCDIC header flag (only a guess) indicating it is meters. Project is in meters so on load the XY conversion option is grayed out.

To override, continue loading the data and convert XY values to meters by editing them in the geometry tab of the settings. If the values are not editable there may be a link to another survey in the same Survey folder. Try moving the survey to its own folder.

Convert a surface to interpretation in Blueback Tools:

This can be done in petrel but the process creates interpretation for all seismic volumes. The Blueback Tools, Surface <-> 3D Interpretation, allows choosing the seismic volume.

Import Grid from XYZ ascii:

To import a grid from an XYZ ascii file you must first import it as “General Lines and Points” (select the “Read as Points” button) then convert to a surface (grid). After importing create a quick surface by RMB on the points and choose “Create/update quick look surface”. This creates a folder below the current folder with a surface having the same characteristics of the points file without extrapolating beyond the limit of the points data.

Process window won’t open:

I have had a process window disappear. Dbl clicking on a process in the process tree typically opens a settings window where you can provide info for the process in question. It this action in every respect seems to be working but you can’t find the window it may be lost off the visible area of the Petrel window. If you are working with a dual monitor setup try temporarily disabling the secondary monitor using window’s desktop RMB menu and selecting personalize or screen

resolution. Then open the process settings window. It will cause the settings window to reposition itself in the middle of the single screen.

How to make autopicked interpretation stop at faults:

Needs an answer.

Show fault interpretation as a trace only in 3D window:

Select the fault’s settings – style and check Restricted Mode.

Hide or show zones in well tops folder:

A lot of tops can make it difficult to find any one of them. Hiding zones can helpyou find a tree in the forest. RMB on the Stratigraphy folder and choose Hide Zone Icons.

Cursor tracking doesn’t work:

Check the windows tree that cursor tracking is checked. Highlight each window in the list. Also make sure you are not in the window positioning mode – hit the esc key once and see if tracking is restored.

Turn off / on one or more well’s tops / markers / picks that they won’t be used in the Make / Edit Surface well adjustment process:

In the Well Tops folder spreadsheet (RMB-Spreadsheet) filter to the well or otherwise find it and all its occurrences in the spreadsheet. At the far right of the spreadsheet uncheck the boxes found in the columns entitled Used by….

Calculate area inside a polygon:

Draw a polygon around the area of interest using Make/Edit Polygons. Open the polygon’s settings. On the Operations tab choose Calculations. Select the Area… and Run. The area pops up in an information window.

Note: For acres, choose the project setting from the main menu and set the area units to desired by choosing the customize icon.

Can’t move seismic lines on basemap with Manipulate Plane function:

With the basemap active make sure inlines and crosslines for the survey are both checked and the line to move is in bold font (active).

Create a polygon line at the intersection of two surfaces:

Open one surface’s setting and choose Operations – and choose Convert Points/Polygons/Surfaces.

Append polygons:

Open settings on one polygon and its operations tab. Go to Polygon Operations – Append Polygons.

Smooth seismic interpretation picks:

Expand the tree under the interpretation in the seismic folder. Open the settings for the seismic volume on which you made the picks and the Operations tab. Then choose Seismic Operations.

Drape an Image (JPG) onto a surface:

1. Remove any rotation and crop the image to the scalable part (rotating is necessary to crop image). You must know the X and Y of at least 3 image corners.

2. Choose File – Import File. Select the format and the image file. OK3. Find the image at the bottom of the Input Window tree and open its

settings.4. On the Settings tab check “Locate in World” and set the button

“Independent Edges”.5. Tip: Petrel identifies the image origin by default as the upper left corner,

but the settings default is the lower left.6. Input three known corners. For now set Z to zero. OK.7. Check the box “Repeat Image Across Surface” tile the image on the

surface if it is smaller.8. In any window except an Interpretation window turn on a surface and

select its settings.9. Under the Styles – Solid tabs set color to Textured.

10. Put the image into the space provided. OK.

Build a depth conversion (velocity) model from a seismic velocity model, cube, or field that can be loaded as a seismic volume:

Most seismic when reprocessed is delivered with the stacking velocity model (PSTM) or the anisotropic velocity model (PSDM).

To make this most applicable it is assumed to be using a PSDM Vz or Vp velocity model provided from the processer and it is in mmm m/s and the project is mmft ft/s this is common in Nigeria.Import the model as is from segy. Realize the result under the the volumes Settings - Operations tab (RMB on volume and choose Settings).

Convert to mmft m/s by opening the seismic settings and the geometry tab and set the sample increment from 10 to 32.8084, if 5 then half the conversion, 20, double

it. You can also set the increment conversion factor before you load the data in the Load SEGY with preset parameters loading process.

Convert the interval velocity values (that is what you have when using a PSDM velocity model) from m/s to ft/sec in the seismic calculator. RMB on the volume and choose calculator. Type “avgvel=yourvolume*3.28084”. Select “yourvolume” by highlighting it in the input tree and clicking the blue arrow left of the equation or selecting it from the list in the calculator window. Click “Enter” and “Realize” the result again.

Note: You can delete the unrealized volumes. Of course, if you’re working in mmm m/s you don’t have to do all this. Just….

Open the “Volume Attributes” process and choose the depth conversion category and the velocity cube attribute. Put your volume in the input using the blue arrow and make sure the settings under the parameters tab are to average velocity and domain convert result. OK.

Again, realize the result.

Note: The process just creates an equation which would have to be applied on-the-fly each time you pick a line from it. Realizing creates a new volume with the equation’s result.

Using the Volume Attributes process:Build an average velocity volume from PSDM Vp model. Realize the volume using its Settings-Operations tab

(uncheck Zero Centric box).

Note: Before you begin be sure Vp model is in the same Z and amplitude units as project. Convert if necessary using the settings-geometry-sample rate and seismic calculator.

I don’t think the “Convert From” is available anymore as the model goes either way (AC/DC). With the model highlighted in the Models tree use it to depth convert anything D2T or T2D where the option is available in the RMB dropdown menu.

In the Make Edit Surface process:Build a depth conversion model by first

creating a flat surface in time representing the model’s base.

Highlight the AvgVel volume and “Get all settings from” it. Think about how deep it should be.

Negative for

subsea

In the Make Velocity Model process:Create a depth conversion model using the model base surface and the average velocity volume. Note: Both

must be in the same domain and left side of “Convert from” set to that domain too.With the depth conversion model active RMB on the PSDM volume and chose Domain convert with active

velocity model.

Compute or Extract an Amplitude or Other Attribute at a surface:

This attribute can be derived using any surface and attached to any other surface.

1. Open the Surface Attributes process and select the Input Seismic from which the attribute will be extracted.

2. Select the attribute class, type of attribute and the surface on which to attach it.

3. Set the window specification, and if one of the two horizon based applications is selected, the surface(s).

Extract a velocity attribute at a surface:

See above:

1. Set Input Seismic to the velocity volume desired.2. Select the Amplitude Class and the Exact Value attribute.3. Set the surface and the From Event to None (with this, the above or below

choice is irrelevant)4. Insure the Search Window Offset is 0.5. OK or Apply.

Set Color Bar (Template) to display Z/Time values in 2D Window:

Problem: In 2D window the color bar defaults to the seismic template and not the time or Z templates of the displayed interpretation.

Solution: turn off the seismic geometry. Inlines and Crosslines can be displayed but not the seismic geometry (parent folder).

Edit the Seismic Geometry Display (Inlines/Xlines and annotation) in a 2D/3D Window etc:

Set these in the parent (survey) folder settings. To set these preferences for each class beneath the parent survey Choose that class’ settings and under style toggle off the button “Settings are inherited from parent folder”.

Displaying the Proper Template or Color bar in a 2D Window (To become more intuitive in version 2012):

Introduction:

Petrel identifies surfaces and attributes by associating them with templates. The template is synonymous with the color bar which defines the values attributable to the colors on the bar which in turn are the colors seen on a surface. Structure grid data is organized as XY Z and Attributes. X and Y are always map coordinates, and Z is vertical time or depth automatically assigned the Elevation Time or Depth template. The attribute may be amplitude or some variation of it computed in by the software. If the software identifies the attribute by virtue of having a template in reserve, it will assign that template to it i.e. average velocity. To see a list of predefined templates in the file tree on the left side of the main window.

On creation the parent surface is assigned a template suitable for its Z component such as Elevation Time or Depth and when displayed in a 2D window the proper template or color bar is displayed in the window corner when the Hide/Show Auto Legend (color bar icon in the tool bar) is set to on (see caveat in the “Set Color Bar….” above).

If you generate an attribute using the Surface Attributes process some may not have a dedicated template. An example is generating an acoustic impedance attribute using a windowed extraction of impedance values with the RMS amplitude feature. The software doesn’t know the attribute is AI and assigns the generic template “Surface Attribute”, but this being a catchall template it is probably assigned to other attributes in your project, and its min and max values may still be set to the previous surface that used it. It can be updated.

To display the correct color bar:

When you display the surface in a 2D window with the color component being one of the attributes the Auto Legend will still be elevation time or depth even though the colors on the surface are of the attribute. To display the correct color bar:

1. Turn off the Auto Legend and open the attribute’s settings by double clicking on it or RMB on it and choose settings from the input tab.

2. Go to the info tab and click the icon right of the template name.

3. Go to the color tab and click the mina and max buttons to re-scale the color bar to the attribute’s data range and click OK and the Settings window Apply.

4. Go to the Settings Color tab and insure the “Override global properties template” is unchecked then OK the settings to exit.

5. Go to the main file tree Templates tab and open the settings for the template. In its style tab select where you want the color bar to be placed and OK. Check the box next to the template, or in point mode (hotkey P) drag the legend where you want it.

Note: For a more permanent solution make a copy of the Surface Attribute template. Rename and reassign the template in the Attributes settings and then follow the instructions above.

Displaying Seismic From Two Surveys Simultaneously or One as a Semitransparent Backdrop to Another:

This can only be done in a 3D window.

1. Set the window’s domain to TWT or TVD using the icon in the tool bar. Vertically rescale the window using the Set Z-scale icon.

2. Open a line from the foreground survey and then click the “Toggle Visualization on Plane” button (blue check boxes) next to the seismic scrolling (DVD Player style) buttons that were activated when you displayed the line.

3. Check the seismic volume next to the survey to be the backdrop. Then turn off Visualization on Plane

4. Open the backdrop survey’s settings and the style tab and ensure the Enable Transparency for Intersections box is checked.

5. Open the Settings Opacity tab and with the tools therein set the transparency color bar as desired.

Tip: If you intend to interpret on the display in Restricted Mode be aware the interpretation must be attached to the parent survey or nothing will show up. Either switch the surveys or copy the interpretation to the parent survey (to do so see these notes).

Tip: Sometimes in a 3D window w/ seismic displayed and the Horizon button set on, the seismic scroll buttons (w/ the Visualization on Plane button) won’t display. One solution is to click in the seismic section as if to make picks. It should pop on and you can undo the click using the undo button or the delete key or erase with the X key.

Unable to overwrite picks at line intersections in a 3D window:

This may be a function of the autotracking settings for the horizon. If picks are made using the guided or 2D seeded autotracking function and the horizon’s autotracking settings are set to Lock Visible Points under the Autotracking – Interpretation tabs as is the default, try changing the setting to Adjust Seed Points.

Display Time Seismic on an Arbline Originally Picked in Depth or Vice Versa:

Inlines/Xlines and arblines are displayed in Interpretation Windows which are assigned a domain of either time or depth. When picking a arbline is assigned the domain and name of the seismic data active when picked. When opening that arbline with a seismic volume not of the same domain active an error message will result and the check box next to the line will be grayed out. To display the data of the opposite domain simply find the survey in the Input Tree and check the box next to it (this would be one branch up from the from the individual inline and xline picks.

Horizon Autotracking on Non Zero Centric Data:

In the horizon’s settings – autotracking tab – Interpretation tab check Non-zero centric and experiment with the picking parameters in the adjacent dropdown menu options.

For impedance data S-increasing or Z-decreasing are two picking methods that work well to track the top and base of a high impedance layer or vice versa on a low impedance layer.

Make/Edit Surface Process Settings Window Opens Off Desktop. Can’t Find Make/Edit Surface Settings Window:

On two occasions, now, the Make/Edit Surface settings window won’t open or opens off the desktop area when activated by double click or choosing RMB – Settings.

The Solution is not certain. That is to say when I have recovered the window I was so mind numb from trying different things that when it reappeared I wasn’t able to recall exactly what steps worked.

If the process settings window is open – and the only way you can tell is if you cannot open any other processes – close it by double clicking on it again but leave it active (bold font). Then at the main menu (File, Edit, View ….) choose the dropdown View menu and select Settings. If you don’t see it then select it again then select Process dialog. If you don’t see it then select it again and go to the Processes window and RMB on the process and choose settings.

It was during the course of trying some variation of the above that the window finally opened on screen.

Another solution might be right-click on the PC desktop background and select screen resolution from the pop up menu (see screenshot) What happens is the dialog can popup on screen 3 or 4 when either is disabled. This screen shot shows screen 2 and 3 enabled. Change the arrangement and try to open the settings. Once I oriented screen 2 to portrait and recovered the settings window that way. This is not Petrel it is the Leostream remote connector.

Tip: Interpretation Window DVD player style tool bar constantly shifts window when window is activated:

This can be annoying when the window is activated by resuming picking and the window position shifts while picking causing incorrect picks. Repositioning the tool bar to maximize the windows size is useless as the tool bar positions itself at the old location on window reactivation causing the window to shift again.

Repositioning the toolbar at the top of the interpretation window next to and on the same row as others that may be there causes the program to remember that location and open the toolbar at the same location each time stopping the constant resizing of the window on each reactivation.

Logging into HP Remote Graphics:

To access Petrel some companies may use a network where the interpreter from his/her office PC remotely logs into another networked PC with the software is installed running it on that PC. A software that provides that functionality is Leostream. The remote PC’s have hostnames. Using the hostname and another software one interpreter can remotely log into a session on that remote PC while it is currently in use by another interpreter allowing the first interpreter to see what the other interpreter see on his/her screen. Both can control the mouse. To be sure

the second interpreter is not logged into the first interpreter’s PC but the PC the first interpreter is remotely logged into.

Software to do this is HP Remote Graphics. To log in to a remote PC as described above open the HP Remote Graphics software installed on your PC and enter the hostname of the remote PC the other interpreter is accessing and connect. The other interpreter has to accept the request and you’re in.

Volumetrics Workflow:

A great way to determine prospect size is to:

1. Make a copy of the surface (highlight – Ctrl C – Ctrl V)2. Blank the surface inside the fault polygons.3. Eliminate the structural area down dip of the estimated contact using the eliminate

function under Settings – Operations – Eliminate.4. Isolate the fault block by deleting areas not of interest.5. Create a polygon around the clipped surface (RMB on surface).6. Delete any unwanted polygons and compute the area.7. Multiply by the thickness.

Bulk shift the surface down by the thickness for a base and a union w/ the contact and faults can create a volume that preserves the edge wedges.

NOTE: You may have to delete portions of the surface outside of and up dip to the contact.

Calculate a difference volume or Subtract one 3D volume from another.

1. Check the settings of each volume that the sample interval is the same.2. Recompute the sample interval for one or both in Blueback Tools Geophysical

Tools.3. Using the RMB over one of the volumes open the calculator.4. In the equation building window enter the equation: 3dvol3=3dvol1-3dvol2

where 3dvol3 is whatever you want and 3dvol1 and 3dvol2 are the volumes to be subtracted one from the other. They are easily input to the equation by highlighting them in the input window and using the blue arrow left of the equation window to insert them.

5. Insure the “–“ sign is between the source volumes.6. Click “Enter”.7. “Realize” the result under its Settings – Operations tab and delete the equation

result.

Display multiple Inlines/Xlines in a 3D Window:

In the Input panel create a virtual volume to limit the size of the lines if desired and use the copy/paste feature to create multiple inline or xline instances in addition to the two that default in the cropped volume.

Tip: Loose your light source? On the dark side of the seismic line? Try turning the light sources in the Windows panel off and on (check box).

Blueback Tools Seismic Spectrum Probe:

When using Blueback tools first make sure the toolbox near the bottom of the Process Tree is active (bold font) by clicking on it. When using Seismic Spectrum Probe, also insure the seismic interpretation window in which you will draw your rectangle is active. If the seismic window is not active then the icon to draw the reference rectangle will not be there. Find the icon and click on it then draw a rectangle around the area of interest. A “Blueback seismic probe” entry will be added at the bottom of the Input tree and it will be checked.

When in tabbed windows mode the corresponding analysis window will not open without selecting it from the main Petrel Windows menu (top left corner) windows tab. It is called a “New Blueback Frequency Spectrum Window”. Open the window and place it as desired.

When done in this order the above mentioned “Blueback seismic probe’ will no longer be checked. Check it and the analysis will display. If not make sure both the Frequency Spectrum Window in the windows tree and the is active as well as the “Blueback seismic probe” are both active then try again.

Create a Horizon or Box Probe:

RMB on a surface and choose “Insert a Horizon/surface Probe” or on a seismic volume and choose “Insert Box Probe”. The probe will be placed in a folder created for it at the bottom of the Input tree. It can be any surface because the surface can be changed in the probe’s settings.

RGB Blending:

1. Open the probes settings and the volume tab therein.

2. Insert two additional volumes or change all three.3. Open the Opacity tab and wait for it to update then click the RGB button

at the bottom right.4. Adjust the opacity and data range sliders.5. Go to the horizons tab.

Creating a time shift RGB Blend:

Time shifts to copied volumes changes the vertical geometry preventing inputting the volumes into the probe.

1. Using Ctrl C/V make two copies of the volume.2. Open the settings of the two copies and time shift one up 12ms and the

other -12ms (time shift is only a suggestion = OGS product).3. Create virtual cropped volumes of all three by RMB on a seismic volume

and choosing from the dropdown menu.4. For each cropped volume choose the settings/cropping tab and set the

Inline, Xline and vertical range the same for each. 5. Realized the results and then delete the redundant volumes to cleanup.

Note: The ranges must be equal to or greater/smaller than the greatest/smallest of them.

Editing the Color Bar or Template:

To make a custom color bar go to the templates tab in the Input, Models, Templates trees and find the appropriate template group. RMB on the group name and insert a new template or copy and paste one of the existing ones in the group. Rename it as desired.

Open its settings and study the block-arrow shaped icons down the left side of the color palate that mark the changes in color, Left click on one and notice the lines to its left change position pointing to one of the color box options and there is a grayish vertical bar connecting that icon with the one above it. The color in the box denotes the color at the arrow icon’s location and the vertical grey bar extending to the arrow icon above it denotes the direction of the color transition to the color at that arrow icon. To change those colors select another from the palate.

The default is to transition from one color to the next. To see how it works change some of the colors. There is no undo button but you can reset using the bottom icon to the right of the window.

To add color segments add another arrow icon using the LMB and clicking between two existing icons. To remove the default transition between it and the

one above click the pencil icon found near the window’s top left that pops up “use two colors” on mouse-over. Set the colors as desired. Experimentation is required.

Delete Autopicked Interpretation or Any Other Pick Type

To delete autopicks, 3D picks, 2D picks or manual picks post the horizon in a 2D window (or maybe a 3D window too) and beneath the folder containing the horizon expand the 3D Interp Inclusion Filters folder. Turn off the types of picks you want to keep and delete the picks still showing as you would normally.

Make/Edit Surface using Additional Inputs Tab

Specifically, Extending an existing surface outward to a polygon edge of a specified Z value or variable Z value different from the z value at the edge of the input surface. In the example image below the input surface is a flat square of constant Z = -1000 ft. and the control polygon has a constant Z = -1500 ft.. The process tapers the input surface to the depth of the larger outboard polygon edge depths and the shape of that polygon.

In a new Make/Edit Surface process window the main input is the small surface. In this example there are no boundary or faults used. The algorithm is Convergent Interpolation and under the algorithm expert tab set the “Number of Nodes to Snap” to 1 and “Order of Projection” to linear. Under the Additional Inputs tab insert the polygon which in this case is larger than the surface. Single click the icon left of the polygon in the input tree you used (turning it blue) and click the

“Get Limits From Selected” under the geometry tab. Click Apply and check your results in the 3D window. In settings - calculations eliminate resulting spillover with polygon. See next subject for use.

Make a 3D GRV Model Volume (Geobody) for a Horizon Top and Base Horizontally Offset From Each Other Such As Along an Inclined Fault Plane for Use in the Make Simple Grid Process for Reserves Calculations.

In the Make Simple Grid Process a volume computed between two surfaces is from the area common to both surfaces. If both surfaces occupy the same surface area there is no problem. But, if the surfaces are horizontally offset, then the common surface area is smaller than both of them. This can occur if the top and base are offset along inclined fault planes.

1. Using copies of the surfaces at the top and base of the reservoir open the settings for the top and Run in Operations – Surface-surface Operations – “A union B keep A” where B is the base surface.

2. Create a surface edge around the result by selecting that from the dropdown menu using a RMB click on the surface.

3. In Make/Edit Surface use the orignal top surface (not the one created in step 1) and the surface edge from step 2 as the Main Input and Boundary. In the Algorithm tab Expert tab set the Number of Nodes to Snap to 1 and the Order of Projection to Linear. Under the Additional Inputs Tab insert a line and put the step 2 surface edge there using the blue arrow. Ok or Apply. QC result. This becomes the top of the reservoir.

4. Using the base surface repeat step 3. This becomes the base of your reservoir.

5. Then either using Make Simple Grid and Volume Calculation or under the top reservoir’s settings – operations – calculations – volume below surface (surface) make the volume calculation.

6. Clean up excess surfaces.

Note: The results can be erroneous if the top and base are widely separated. In the example below, the top and base separated by 1000+ feet, the 3D model was created using manual interpretation picks connecting the surfaces’ transitions to each others’ edges. Another 3D model was created using the technique above. The area

difference was 10% and volume difference 3.2%. Minor in many respects, but the automatically generated sloping flanks on the surfaces did not track by a wide margin where the hand picks had been made.

Top left: Input Horizons. Top right: Process Result.

Left: Manual Picks Result.

The differences may be remedied with some careful edits to the input surfaces.

Well Section Curve Header Has Wrong Units or Insufficient Decimal Precision

1. In the input window under Wells – Global Well Logs open the offending curve’s settings and check that the Template is consistent with the curve type i.e. if it is a Vshale curve the template is Vshale or appropriate.

2. If it is then under the tree Templates tab find that template and open its settings and set the “Show numbers with” to the desire number of decimal places.

3. If not then set the template to the appropriate one from the drop down list and repeat step 2 if necessary.

4. Updates to the curve in the Well Section Window may not be automatic. Click Apply and/or OK to close all settings windows and if necessary “Touch” the log curve under the Well Name or Global Well Logs folder in

the Wells folder under the tree Input tab by opening its settings and selecting OK.

Calculate Autopicked Amplitude Area or Create a Quick Look Surface

You have autopicked an amplitude and want to calculate its area for a reserves estimate. There are three quick ways to do this. The first two, I believe, are available in Petrel without plugins and work well but the other is only available through a Blueback plugin you may or may not have.

1. Expand the interpretation tree (click the + left of it) to expose the seismic volume on which it was autopicked. RMB on that volume and choose “Create / update quick look surface” and then “Create / update boundary polygon”. These results will be placed in like named folders at the bottom of the input tree. The polygons area can be computed in its Settings – Operations – Calculations.

2. If this functionality is not available due to its being tied to plugins you don’t have try converting the interpretation to points. A similar functionality exists for points though it has been inconsistent.

3. If you have a proprietary plugin installed then expand the tree branch under the horizon in the interpretation folder and RMB on the survey listed there (this should be the survey on which you picked the amplitude extent). Choose Settings – Structural Analysis tab and expand the Structural Analysis tree branch choosing Automatic Boundary Polygon. Check the Outer Polygon Only box and click “Run”. The result is found in a folder “RDR Bounding Polygon Data”. Compute the area(s) inside the resulting polygon(s) as in workflow 1 above.

Expand or Shrink a Surface (Grid) Larger or Smaller Than Its Containing Polygon.

Open the surface settings and the More tab. Set the number of grid nodes and Expand or Shrink.

Append / Connect / Join Two Faults:

In point mode (arrow icon) using the CTRL key select the points or lines to join and then click the join function icon (left of the fault interpretation icon).

Change Color Bar Display:

To Change the display of a color bar in a window go to that window in the Windows tab tree and expand the settings of the window by clicking the + icon next to it. Open the setting of the Automatic Legend Option.

Map Window Object Layering and Ticks

Under the Windows tab of the main project items tree defaulting at right on Petrel opening, expand the Map Window item tree and open the settings of the Map 1 folder. Under the tab, layering, reorder the listed itmes.

Ticks can be turned on and off using the Show/Hide Axis icon on the tool bar when the map window is active. Also, if you want to leave the border ticks on and turn off the internal ticks expand the Map Window tree in the Windows tab – Dbl click on Axis – go to the Grid tab -- uncheck all the boxes under Show Grid. It is here you can set the character of all ticks.

Inline Crossline Readouts at Cursor

Try using the Inspector Tool found first in the list under the View option off the main menu. Using the little gear wheel icon next to the X icon used to close the window, open the settings and check Continuous.

Also, a trick is to create an Empty Cube from the geometry tab under the settings of the main Survey folder in the Input window. Give it great depth and turn on a deep horizontal slice from it. At any mouse position on the slice it will give you a inline/xline readout.

Export Well Logs to LAS

Under the Wells folder in the Input window RMB click on the well and choose export. Navigate to where it’s to be stored and name it including the extension .LAS. Click save. On the next window change the default from “From Selected Log” to “Specified MD” (I have had mixed failure using “from Selected Log”) and enter the start depth – 0 for all. Enter the step or increment. Standard is .5’ or whatever for meters. Select the logs. OK

Note: If no data exists for the depth a standard null value will be used.

Extract Well Picks From Surfaces.

1. To keep results separate from existing tops create a new well tops folder using the “Insert” drop down menu off the main menu (this may be automatic).

2. Open the Wells folder settings and the Report tab.3. Make your new well tops folder active (bold type) by clicking once on it.4. With the control key depressed (if more than one surface) single click on the

surfaces, highlighting them, on which you want the picks.5. Under the Wells – Settings – Report tab check “Make Well Report” and “iconize

points as” and select the “Horizon in active well tops” button.6. Click the icon starting with “append….” From the list at the right of the text

placing the surfaces highlighted earlier in the list at right.7. Click “Run”. A report results and the well tops will populate the newly created

folder.

Add / Edit a Well KB Elevation.

1. RMB on the well and open the wells Settings => Settings tab.2. Under the Reference Level click the icon to add a row.3. Make the required selections. Depths above MSL are positive.4. Highlight the new entry or another entry if more than one exists.5. Click the green check icon to make it active. The reference level should then be

indicated in the directional spreadsheet.

Fault Throw Analysis

This may be a Blueback Tools feature but under a faults settings is a tab for Structural Analysis. Expand the Geometric Analysis tree to find Fault-Horizon interpretation Intersection. Click on this and add 3D Horizon Interpretation from seismic picks by expanding the tree on a horizon and selecting the 3D volume on which the horizon was picked placing that in the space provided using the blue arrow or click-and-drag. You can toggle off the two horizon options if desired (experiment if desired). Then click run.

At the bottom of the Input tree a RDR folder is created and in it is another folder called Throw Profile Data. Drill down to the last nested item designated by a XY graph icon. RMB on this and select spreadsheet. What opens is a spreadsheet of the throw or offset across the fault on the horizon interpretation. In another folder there is a polyline showing where the fault intersects the interpretation.

Combine Checkshots into One Global Checkshot for All Wells.

Couple of ways to do this: the manual way and the automated way. If there are only a few just make a copy of one (highlight it then hit Ctrl C and Ctrl V) and rename it to All Checkshots. Open the settings for it, go to the Operations tab and find Common Operations and Append Points with Attributes. Under Points to Append highlight each of the other checkshots and insert them using the blue arrow and Run. Repeat this operation for the others until done. For a lot you can write a workflow to automate the operation. A workflow is a way to program all the steps above to run in a loop until done. Afterwards, under the Wells folder Settings - Time tab set the new All Checkshots as the Global Checkshot and make sure the same settings for the wells in it do not have the override global checkshots box checked.

Build a 3D Grid for Depth Conversion Using Checkshots.

There are a couple of ways to prep your checkshots for this process in Petrel. You should consider creating time depth relationships (pseudo-checkshots) in wells without checkshots by borrowing from a nearby well and synthetic tying the well saving the edited checkshot (see Seismic Well Tie these notes). Combine all the wells’ checkshots into one global checkshot (see workflow these notes above). Once you have merged your checkshots into one global checkshot open the Wells and Global Well Logs folders and expand your merged checkshots. RMB on the Average Velocity attribute and choose convert to log. This will create an average velocity log from the time - depth relationship for each well in the merged checkshots. After that the process is the same as building a geomodel.

1. Begin by building two surfaces in depth that define the 3D grid area in X, Y and Z. This might be the seismic survey area or use a surface you already have that you simply change the depth to a constant in its Settings – Calculator. You can open the Make/Edit Surface process and use the geometry of your 3D seismic volume or a polygon and set the algorithm to Artificial Algorithm. Be sure to use a negative for depths below 0. The top is usually 0. Copy that surface using ctrl-c and ctrl-v and set the new surface to the base in its calculator.

2. Open the process Make Simple Grid and set to Create New and Insert Surfaces. Insert your Top and Base. Select the Geometry tab and set to automatic if your surfaces are that or set to get geometry from another source such as your seismic. This is important as it defines your grid orientation. Check the grid increment too. OK. To edit make it active and open Make Simple Grid.

3. With the 3D grid active select the process Layering under Corner Point Gridding or Structural Modeling. This is the Z or thickness of the grid’s

cells. Leave or set the layers to proportional. Calculate the thickness using (Bottom Model – Top Model) / # Layers. Input the # layers to get the desired thickness. Alternately you can change proportional to Follow Top and input the layer thickness. OK

4. With the 3D grid active select the process Scale Up Well Logs under Property Modeling. Set to Create New Property and Well Logs. Select you Average Velocity log from the list. Insure all wells are selected and OK. Select the property from the 3D grid in a 3D window. It should plat along the well paths.

5. Select the process Petrophysical Modeling also under Property modeling. Click the small padlock icon to unlock the process. Choose a method of interpolation – Moving Average is simplest. Here you can include an average velocity volume from seismic as a trend if one has been scaled up to the grid (see how elsewhere in these notes). You’re on your own to study the other options. OK should start a computation process that will result in a 3D color cube of average velocity in a 3D window. In the function bar (usually at right) select the I, J or K icons to see a cross section through the property. It should match the wells at the bore hole and transition to another between wells.

6. You can check the model velocities at each well location by opening a Well Section window. Choose a template and check a well from the Wells folder. Expand that well’s tree and Well Logs. RMB on the average velocity log and choose add to template in a new track then check the average velocity property from the 3D grid’s properties.

The grid can now be used in the Make Velocity Model process for depth conversion.

Up-Scale Seismic into a 3D Grid.

To Add Seismic Velocities as a property to a 3D grid use the Geometrical Modeling. The available methods are numerous making this a potentially powerful tool.

1. Make your 3D grid active.

2. Open the Geometrical Modeling process and set to Create New.

3. Under Method choose Seismic Resampling (may not be available without a seismic license).

4. Drag and drop or highlight and use the blue arrow to add the average velocity cube to the process (here average velocity is used generically to describe any velocity volume where the values are all referenced from the surface such as stacking velocities).

5. Choose the Quality and Averaging Method (see the help icon).

6. Mouse over Use Zone/Segment Filters for more info.

7. OK

Create a Custom Contour or Contact Contour.

There are two processes for this. One creates a contour in 3D gridding that can be annotated under model building using the Make Contacts process under Corner Point Gridding. The other make a line of intersection and cannot be annotated.

1. Open the settings of the surface and the Operations tab.

2. Expand Convert Points/Polygons/Surfaces.

3. Choose Create Intersection with Plane and input the depth in negative numbers.

4. Click Run.

The contour is a polygon and is edited as such and can be used in Calculations.

Create a Net to Gross or Percent Grid From an Attribute.

From an attribute attached to a surface RMB and choose Convert to Surface. Using the new surface’s Settings – Calculator render it to all positive values. Under Settings – Operations expand the common operations tree and select Normalize. Be sure the min and max are set to 0 and 1 and click run.

Prepare a Fault for Fault Modeling

A fault can be prepared for Fault modeling by opening its Settings – Operations – Convert Points/Polygons/Surfaces and selecting Create Clean Fault. A set of fault sticks result at bottom of the Input Tree that can then be modeled.

Another technique is to convert the fault to a surface in Make/Edit Surface and then smooth it in the Settings – Operations – Surface Operations. Then the surface can be converted back to a fault or from the surface directly to the model using “Convert to Faults in Fault Model on a RMB.

Prepare a Surface for a 3D Geologic Model (Geomodel)

A surface should be reduced to not much more than the reservoir area. Though it can be handled in the model building process, you can eliminate the little-up turns along fault traces by shrinking and then expanding the grid by 1 bin in the Settings – More tab. If a fault is a reservoir boundary make it a grid boundary in the model in Pillar Gridding.

Build a 3D Geologic Model (Geomodel)

The Corner Point Gridding processes are listed in the order they are accessed in grid building though some processes can be skipped in simpler models.

Before you begin you should try to make your interpretation as precise and clean as possible. Check your fault and horizon interpretation in a 3D window and make sure your picks tie well forming as smooth a surface as possible. Use an interpretation window to make adjustments to picks. Delete picks you can’t edit such as those made on random lines you didn’t save. Horizon interp can be converted to surfaces (grids) and smoothed but faults are a bit tougher. Define those with as few picks as possible on inlines and xlines only. You will thank yourself later.

1. Double click Define Model, give it a name and that process is done.

2. If you have no faults stop and go to Make Simple 3D Grid instead. With Simple 3D Grid you will skip the Pillar gridding process. All the other tasks, Layers, Upscale Well Logs and Property gridding are the same. But if you have faults there are a number of ways to get a fault into the model. Not all are desirable. Be sure your model you just created is in bold font – that means it is active. If not then LMB click once on it or its icon to make it bold font. Open the Fault Modeling process with a double click. On opening the process some icons will appear in the function bar – found at the far right of the larger workspace desktop on my Petrel layout. Open a fault’s settings (double click or RMB) and the operations tab. Under

Convert Points/Polygons/Surfaces select Create Clean Fault and Run. A fault stick file is created at the bottom of the input tree. Move it where you like and single click on it giving it white bold text on a blue background (thereby making it active and selecting it).

3. You may not need to import the fault from top to bottom. On the operations tab of the fault modeling settings you can limit the import to a constant top and bottom depth or between two surfaces. Set as desired.

4. Click on the fault type icon on the function bar on the left side of the workspace window as (see the fault modeling settings – hints tab for an example of what it looks like for your fault type) then on the Create Fault icon nearby in the same function bar. Repeat for more faults.

5. In the Fault Modeling settings window Operations tab click cut extend to clip the faults according to your settings.

6. Edit the faults if needed by clicking on the anchors points with the select tool (white block arrow) and moving them about. You can also add or delete fault pillars.

7. If the faults intersect you might try the auto connect function in the fault modeling settings operations tab too. Intersecting faults will have to be joined, having a common pillar

8. Open the Pillar Gridding Settings tab (a 2D window will open and become active) and name your grid or set to edit a grid. Set the I and J grid increment.

9. The 3D grid has to have boundaries. These are at least as big as the reservoir if not bigger. If a fault constitutes a boundary to the 3D grid then in select mode (white block arrow) click on the fault once, thereby selecting it, and click the icon in the function bar with the letter B on it (mouse over it to confirm it says “Set part of grid boundary”). Repeat for other fault boundaries.

10. Other boundaries may be needed to complete the loop. Digitize these using the icon (tool) Create External Grid Boundary. Start on an existing fault boundary and end on another. Finish with the middle mouse button. They must terminate at the end of fault boundaries (verification needed). You can add/edit points by selecting the boundary with the select tool and then editing like any polygon.

11. If a fault trends prominently as a boundary set the J or I direction parallel to it. Turn on the fault’s anchor points using the Show Points icon in the function bar and either select the whole fault or specific anchor points

using the shift key then set to the J or I direction using the appropriate icon in the function bar. The I and J direction can also be set manually by angle rotation under the Expert tab.

12. Trend lines can also be digitized in Pillar Gridding to guide facies or channels (Needs additional guidance. For now see help).

13. Apply to build the 2D grid. If you picked your I and J trends wrong (I always do) a message will open offering to correct it; click OK and OK again to build the 3D grid. Some information and approval windows may open in the course of it. Examine the faults and grid skeleton. It should look like a nice little wire cage. If not edit the faults as necessary.

14. Do what you need to do to your horizons to ready them for import and double click on the Make Horizons process. Under the Horizons tab click the icon at left to insert rows into the spreadsheet. Single click on each horizon in the input tree and click the blue arrow next to Input #1. Do the same for the corresponding well tops. Read the Hints tab and all else under the other tabs and adjust as necessary and if you understand them. Otherwise leave the defaults. OK. Check the results in a 3D window. If the horizons are conformable they should not intersect. You may have to go back and fix the horizon in interpretation. In a 3D window display the horizons and turn on Edges as a QC. Tip: To make a base of sand horizon RMB on its top horizon in your model and choose Convert to Structured Surface. Then open that surfaces settings and in the calculator add some depth. Change its name and use it in the Make Horizons process to make the base sand. Works with other calculations too but it’s not the same as an ordinary surface so there are limits to what you can do. Run with it.

15. If you are not in depth at this time perform the depth conversion process. See how to build a depth conversion model in this Document.

16. If there is a Horizon or Surface you couldn’t pick on seismic such as the base of a sand you can add it using Make Zones. Make Zones allows you to build a horizon from well tops. Double click on Make Zones. To add a base A sand, at the window top set the Stratigraphic Interval relative to the zone you are adding – Top A sand to Top B sand. Set the Build From to Top Horizon. Click Append Item to Table (Left most icon). Click on Horizon and rename it. Set the Input type at the top zone to Constant and the input of the bottom zone to rest (what’s left over). Then Apply or OK. Tip: Adding horizons or zones to your model will require you to upscale well logs again. Upscaling logs again will delete any petrophysical modeling you did before.

17. With the 3D grid active select the process Layering under Corner Point Gridding. This is the Z or thickness of the grid’s cells. Leave or set the

layers as desired. Calculate the thickness using (Bottom Model – Top Model) / # Layers. Input the # layers to get the desired thickness. Alternately you can set to Follow Top and input the layer thickness. OK. Tip: Remaking horizons will reset you layering to 1.

18. Geometrical Modeling allows you to incorporate properties into the model that are not well log derived such as a net to gross map or surface, seismic velocity volume in segy. Suppose you have a surface grid depicting N/G sand. Open Geometrical Modeling and set to Create New. Choose as your Method under Settings: Constant or Surface in Segments and Zones. Set the Property Template to N/G and choose the zone to which the property applies or check Same for All Zones / Segments (fault block) if one input applies to all. Uncheck the Same for All Zones box and check the boxes beside the zones you’ll input surfaces. Input the N/G surface grids using the blue arrow. One property will be created using all. A seismic example is described above under Up-Scale Seismic into a 3D Grid. Tip: A zone index can be uploaded as a Geometrical Property as well. Select as your Method, Zone index.

19. Property contact set.

20. With the 3D grid active select the process Scale Up Well Logs under Property Modeling. Set to Create New Property and Well Logs. Select your log from the list. Insure all desired wells are selected and OK. Select the property from the 3D grid in a 3D window. It should plot along the well paths only between the horizon zones. Tip: Upscaling logs again will delete any petrophysical modeling you did before.

21. Select the process Petrophysical Modeling also under Property modeling. Click the small padlock icon to unlock the process. Choose a method of interpolation – Moving Average is simplest. You’re on your own to study the other options. OK should start a computation process that will result in the wells’ property being distributed about the model zones tying at the well control. In the function bar (usually at right) select the I, J or K icons to see a cross section through the property. It should match the wells at the bore hole and transition to another between wells.

22. You can check the model properties at each well location by opening a Well Section window. Choose a template and select a well from the Wells folder. Expand that well’s tree and Well Logs. RMB on the log from which the property was made and choose add to template in a new track then select that property from the 3D grid.

Tip: Add a General Intersection by RMB on the Intersections folder of your model and choosing Insert General Intersection. Use any of the eye dropper icons to reorient the line.

Condition and Smooth a Hand Drawn Polygon

After digitizing a polygon it looks like toothpicks laid end to end. A good way to condition it is to first Interpolate the Selected Polygon and then Smooth it using the icons in the Polygon Tool Bar. The smoothing option may not be necessary as interpolation smooths as well.

Fault Modeling - Digitizing a Pillar Fault using an Existing Fault

Rather than importing fault sticks to the model you can digitize fault pillars into the model using the sticks as a guide. With fault Modeling active from the Tools bar activate the Curved Pillar icon for complex faults and then the Add New Pillar icon to start picking fault pillar anchor points. Clicking on the fault sticks attaches an anchor to the stick and each additional click up to five defines the pillar. An anchor for any one pillar can be attached to any stick. It does not have to follow just one stick. When picking a Curved Pillar it automatically ends after the fifth anchor. Move to the adjacent pillar and start anew. The undo button removes the last anchor or the last pillar. It needn’t be a pillar per stick but just enough to define the fault as needed.

If this is the first fault added to the model it will automatically create it in the model’s Fault Model folder as Fault 1. It will also be bold font while picking it. To start a new fault click the first to make it not bold font then start picking another and a new Fault 2 will be created.

Create a Fence Diagram of Model Properties

In your static model open the Properties – Settings – Filter tab. Check Use Index Filter and set the Width and Skip factors then select a property.

Build a Model Property Dividing the Entire Property Region into Two Regions Separated by a Fault Surface Grid.

This is a special circumstance where the fault exists as a plane having dip very acute relative to the dip of the bedding plane. In this scenario the fault splits grid cells down the middle along the cell’s Z axis causing spurious anomalies.

A trick is to use the fault grid combined with Layering to halve the model into two regions – one of the footwall and another of the hanging wall. In the Geometric Modeling process a property, say “Fault Regions” is built using the Method “Assign Between Surfaces and Polygons”. The Property Template is General. Assign as a Base Surface a grid of the fault plane (created using Make/Edit Surface). In the Value to Assign Between Surfaces set to “Value” in the dropdown menu and enter 0 in the box. In the Assign The Other Cells To set to Value and 1. This will create a property with the hanging wall block cells set to 0 and the Footwall block to 1. Define all your other properties across the entire model area and then eliminate the hanging wall side using the Properties Calculator (RMB on Properties folder) with the expression: Porosity=If( Fault_Regions=1,Porosity ,U )

Fault Region Property Porosity Property Footwall

Create a Geomodel Workflow

As you manually build a geomodel you can at any time create a workflow of the steps you used to build it.

At a point where you have completed a process such as Pillar Gridding click on the Workflows tab thereby activating the workflows tree and RMB in the window choosing Insert Workflow. In the window that opens find the link at bottom right “Auto Generate workflow” and select Repeat all Calculations in the 3D Grid”. This will populate the workflow with all the step you did in Pillar Gridding. You can then make edits by clicking on any of the blue font entries and rerun the process.

A Geomodel Workflow Example

I created a geomodel with 5 sands separated by 4 shale beds and captured the process in workflows. Captured images of them are below.

Insert a General Intersection into a model

RMB on the Intersections folder and choose Insert a General Intersection. Turn on the Blue Check Boxes (Toggle Visualization on Plane Ctrl+B) and select an Item to display from the model.

To reposition the plane one of the two eyedropper icon for Snap the Intersection to a point or 2 points.

In a 3D window select the M keyboard button to click and drag the plane across the model.

Build Gas/Water, Oil/Water or Gas/Oil/Water Contacts Model Property

Make Contacts puts a flat 2D plane through the model that cuts across Zones to which it doesn’t apply. A dressier way is to create a contact property by opening the Contact Set folder Settings – Operations tab. Select the contacts to use and what fluid exists below the contact then click Make Property. Turn on the property in your model to see the zone separated by red, green blue at the contacts.

Compute GRV Surfaces From Top and Base Horizontally Offset as by Faults or Diapirs

A top and base of a reservoir offset by a fault or diapir flank gives a cross-sectional view of a parallelogram. The Workflow below fills in the diagonal flanks along the fault/diapir surfaces giving the top and base the same surface area (footprint) for GRV calculations using the top surface’s Settings - Operations – Calculations , or for use in Make simple grid where the calculation is only done on the area of the union of the two surfaces.

Create an Off/On Property the Cells of which are Values of 1 or 0

Possibly used in the Property Calculator to filter other properties.

This Geometrical Modeling property can be used to carve off a portion of another property along an unconformable surface or unthrown or up/down thrown to a fault not represented in the model.

In the Properties Calculator under a RMB on the active model’s Properties folder enter the function “Zones_Clipped=If( Thrust_Foot_Hanging_Wall=1, Zones_hierarchy, U)” substituting your properties in the function.

Edit a Polygon Using the Keyboard

There are at least two ways:

1. Under the polygon’s Settings – Edit Rectangles tab (if that’s what it is).And RMB on Polygon in input window and choose spreadsheet.

Reserves Calculation Error after Applying Formation Volume Factor (FVF)

My reserves were being incorrectly computed in the Volume Calculation process. I knew this for two reasons: The value was suspicious and the result didn’t match a reserves spreadsheet I made. I thought it was a bug and so did the onsite support guy.

Turns out the gas FVF had the wrong units applied in the template. After much discussion with an engineer who inadvertently planted the thought I check the units in the template for the Gas Formation Volume Factor to find it wrong. How it got that way is unknown. After trying a number of other settings I found any dimensionless units (ft/ft, m3/m3, rm3/sm3 etc.) to work and changed the setting to “dimensionless”. Mixed units like f3/ac-ft gave the wrong results. My was set to RB/MSCF for some reason.

Can’t Delete Seismic Volume Folder

If you can’t delete a seismic volume folder in the Input pane just beneath the main seismic folder it may be because there is still interpretation attached to it. Expand the tree for each of your interpretations and check that it does not have listed the offending seismic volume. Delete it and delete the survey’s folder.

Extract a velocity log for all wells from a velocity volume. The result is in the form of time/depth pairs.

2. Open the velocity volume’s settings and go to the “Operations” tab. 3. Expand the Velocity Conversion option in the tree.4. Select Time Logs, set the increment and hit Run.5. Find the log under each well’s Logs Tree.

You can also extract a velocity log for one or all wells using the “Global Well Logs” calculator (RMB on the folder in the Input tree) or calculator under the individual well folders (see below).

The setup extracts from any volume the amplitude component of that volume to a log having the name indicated left of the = sign. It must be attached to a template (hopefully one that matches the data extracted but anything seismic will do. It just controls how the result is displayed or what the computer thinks the data is.) The sample rate (increment) can be adopted from another log or specified, but one has to be chosen.