scm bitmaps in interpretation petrel 2010

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Petrel is a mark of Schlumberger

4801 Woodway Drive, Suite 150W Houston, TX 77056 www.scminc.com [email protected]

2010 SCM E&P Solutions, Inc.

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K n o w l e d g e W o r t h S h a r i n g

Petrel TIPS&TRICKS from SCM

Bitmaps in Interpretation

This TIPS&TRICKS illustrates the process of importing and geo-referencing map and seismic data

bitmap images, and how they can be used in interpretation workflows. This type of data is easily

obtained from professional society and other technical publications, or from a corporate archive

database. It can be used to fill gaps in the existing project data or incorporate the results of previous

studies in the current interpretation. Image data must be loaded and geo-referenced properly

before being used in Petrel. They can be positioned either horizontally as a slice, or vertically as a

profile.

Map images oriented as a slice can be used to guide the creation of contours, and cultural data, as

well as draped on existing surface interpretations to enhance visualization and control quality.

Seismic data and geologic cross section images can be obtained from literature and loaded as profiles

to guide interpretation.

Import

Images are easily imported to Petrel using the Bitmap image (BMP,JPG,TIFF,GIF,PNG) file type option

in the import window.


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Petrel is sensitive to the image file size. Large image files may not load. In this case the file needs to

be rescaled outside of Petrel to a smaller size for import. Cropping the image outside of Petrel to

remove any unnecessary data will further reduce the file size and make positioning easier.

Once the file is loaded it must be located correctly in the world, or geo-referenced, for use in

interpretation. This requires that several points, whose locations are known, are loaded into the

project and also exist in the image for reference. The accuracy of positioning images in Petrel is

limited by constraints imposed by the software. Images are positioned using only 3 pointscorresponding to corners of the image. Reference points other than 3 corners of the image must be

tied visually by trial and error adjustment of the X, Y, and Z coordinate of one or all of the three

corners in a display window. Further limits on the accuracy of positioning are imposed by the fact

that the image can only have 4 sides or borders, no hinge lines are allowed, and opposite sides must

be parallel. This impacts the positioning of 2D seismic profile images the most due to the fact that 2D

seismic lines are rarely if ever straight. Therefore, irregularly shaped or hinged 2D seismic profile

images may not be appropriate for interpreting in this manner. 3D seismic inline and crossline

profiles are straight by design and are more suitable for this type of interpretation.

Map Data

Images must be located, or geo-referenced, correctly in the world before interpretation begins. The

image can easily be given a general location initially by using data already in the Petrel project.

1. Open the Settings of the image by double clicking on it in the Inputtab.

2. Select an object in the Inputtab you want to use as reference and make it active. An active

object has bold font in the Inputtab.

3. Select Set from selectedto get the location limits from the existing object.




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3. Change the method to Independent edges and fine-tune the position by adjusting the X and Y

coordinates to align reference points common to both the project data and the image.

Reference data commonly used are well locations and property boundaries. Skewed,

distorted, or otherwise poorly produced images will be difficult to position accurately.

Once the image is positioned correctly it can be used to enhance visualization of an existing

surface.

1. Open the Settings dialogue window for the surface you want to enhance.

2. Go to the Style tab.

3. In the Solidsubtab, change the color option to Textured.

4. Use the blue arrow to enter the image file as input in the box that appears.




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Faults and contours are digitized using the Make/edit polygons process. Digitize each fault and

contour using the image as a guide.

1. Display the geo-referenced image in a 2D window.

2. Activate the Make/edit polygons process.

3. Create a new polygon file for the faults.

a. Click on the Make/edit polygons icon .

b. Click on the Start new set of polygons (deactivate old) icon .

4. Digitize the fault following the image as a reference.

5. Click on the Start new polygon on active set of polygons icon , or press the N key on your

keyboard to end the fault and start a new one.

6. Repeat the process, pressing the N key on the keyboard at the end of each continuous fault

line, until all of the faults are digitized.

7. Create a new polygon file for the contours.

c. Click on the Make/edit polygons icon .

d. Click on the Start new set of polygons (deactivate old) icon .

8. Digitize the contour following the image as a reference.

9. Click on the Start new polygon on active set of polygons icon , or press the N key on your

keyboard to end the contour and start a new one.

10.Repeat the process, pressing the N key on the keyboard at the end of each continuous

contour line until all desired contours are digitized..

11.Click on the Pops up Z-Value selectoricon .

12.Enter a z value you want to assign to a contour.

13.Click on the Select and edit line icon , select the line you want to adjust, and click on the

to set the z value for the contour.




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The digitized contours and faults can be used as input in the Make/edit surface process.

Seismic Data

Seismic profile images can play an important role in Petrel interpretation workflows. Useful

images are often included in technical reports and publications and can be used to provide insight

or guide an interpretation. They must have features that enable them to be accurately geo-

referenced with objects already loaded to the project. Features like IL/XL or CDP/SP annotations

are required to accurately orient the image geographically. You will also need time/depth

annotations to properly scale the image.

The following example uses images from a publication to help guide a new interpretation in the

same area. The seismic profile image does not have IL/XL annotations. Another image shows the

location of the seismic profile image in relation to a known reference. The seismic profile image

will be positioned in map view based on this and then fine-tuned and adjusted in depth toexisting seismic data.

Base map image Seismic profile imageProject reference data




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1. Import the base map image showing the seismic profile image location.

2. Geo-reference the base map image with the field boundary polygon that has been loaded

to the project.

3. Create a polygon that represents the line of section for the seismic profile image. Make

sure that the template of the polygon matches the domain of the seismic.

4. Copy the line of section polygon 3 times and set the Z value of each to match one of the

depth annotations on the image (-500, -1000,-1500) to be used as reference.

5. Import the seismic profile image. Use the line of section polygon to initially position the

image.




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6. Adjust the coordinates to position the image vertically.

a. Deselect the Relative to selected Originbutton.

b. Select the Independent edges option.

c. Set the origin (lower left) depth coordinate to -1600

d. Set the X and Y coordinates of the lower right corner to match the upper left

corner, and the Z coordinate to -1600.

e. Set the X and Y coordinates of the upper left corner to match the origin, and the Z

value to 0.

f. Click on Apply. The image should now be positioned vertically along the line of

section.

7. Display the 3 depth reference polygons created earlier in a 3D window.

8. Adjust the Z coordinates until a visual match is established with the reference polygons.




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9. Create a vertical intersection from the line of section polygon by right clicking on it and

selecting Create vertical intersection.

10.Display the project seismic data in the vertical intersection by clicking on the blue button

or using the keyboard shortcut Ctrl B and selecting the volume to display from the input

tab.

11.Make a copy of the line of section polygon and use the Equal space operation to insert

points at regular intervals to use in positioning the profile image.

12.Adjust the X and Y coordinates of one side to closely match the project seismic displayed

in the vertical intersection using the points created in the previous step as reference.

13.Display a seismic line from the project that intersects the image and fine-tune the image Z

coordinates to obtain a visual tie. Differences in the data used in the image and the

seismic in the project may prevent an exact tie.

NOTE: Images in Petrel are restricted to the depth domain. It cannot be changed by the

interpreter. In order to display with time domain seismic you must set the domain of the display

toAny. This is just a technicality because the image is referenced to the scale of the project

seismic data, regardless of the domain.




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scm bitmaps in interpretation petrel 2010

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