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Petrel Resampling 2D lines into a 3D Grid P. 1 OF 8

Petrel 2009: Resampling of 2D lines into a 3D grid Sometimes clients would like to resample their 2D lines into a 3D grid. In Petrel 2009 the use of the geometrical modeling property Seismic Resampling is only supported for 3D volumes. One solution is to create a point set at the sampling rate desired along the 2D lines, and use the operation Assign values from a seismic cube to create a seismic attribute for this point set. Then the point set can be

upscaled into the desired 3D grid for analyses or used as a proxy as required. This is a particularly useful workflow when other workarounds, such as loading the 2D line as 3D in order to be use in the standard seismic resampling workflow, does not work as in the case for crooked 2D lines. This method has been outlined in detail below for reference, however using the attached workflow it is relatively simple to generate the point set based on the desired resolution and resample into the grid.

1. Generate line layout from 2D seismic line

This can be done by right clicking on the line and using the context menu to generate a line layout. Note: This can be performed for the entire survey at once using the context menu from the survey folder instead.

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Petrel Resampling 2D lines into a 3D Grid P. 2 OF 8

You will be prompted to generate a seismic layout polygon. For 2D lines you have a choice to generate this polygon based on every nth trace. Choose for every trace (1) if you want to create an exact layout and want to generate a point set where the lateral sampling rate is as dense as the seismic. If this is not necessary, you may choose to decimate this polygon by required factor depending on the 3D grid lateral resolution which the point set is going to be upscaled in. By decimating the polygon you save processing time however you need to be careful and make sure you are creating a point set which still going to give you the most information possible depending on the resolution of your grid.

Press OK and you will see a polyline generated called Seismic line layout slb1 where slb1=line name.

2. Produce a point set with desired vertical sampling and length.

A point set can manually generated by copying the seismic line layout several times (depending on the desired vertical resolution) and use the Calculations tab to change to Z value for each layout. This can be tedious manually so a workflow has been created such that a point set will be automatically be generated based on the desired vertical sampling rate and length (provided in attached project). After you have generated your seismic line layout at desired lateral resolution, the next thing you need to decide is what vertical resolution you want. You can either look at the resolution of your seismic or grid. If you choose your seismic first look at the seismic trace extent. You can view this by right-clicking on the seismic line and choosing Settings. Then go to the Statistics tab and take note of the trace.

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Petrel Resampling 2D lines into a 3D Grid P. 3 OF 8

In my case the trace extent is 8000. In the same dialog window you can determine what you sample interval was (in my case 4). This means is I want to preserve the sample rate I will need to have 2000 loops (delta trace/sample rate = loops).

The seismic sampling rate was chosen for demonstration purposes. Alternatively I could have chosen to decimate my sample rate based on what I need or ultimately matched it to the 3D grid resolution. The resolution and extents of the grid can similarly be check from the Statistics tab in the settings for the grid. The advantage of decimating the resolution to at least match the grid is the workflow will generally run substantially faster. This will generally be a user choice based on hardware capabilities but it is generally recommended to create a point set at grid resolution. The first part of the workflow will generate a Temp folder where you generate all the copies of you 2D lines layout and set them to a particular Z values, depending on desired resolution of point set. Inputs here are the seismic line layout, the loop number, the sample rate and the top depth.

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Petrel Resampling 2D lines into a 3D Grid P. 4 OF 8

The second part of the workflow will take all these generated polygons in the Temp folder and append them, then move them to the Final folder. We will remove the Temp folder at the end of the workflow for clean up purposes as it isnt necessary to QC or view the results, but if desired this line in the workflow can be disabled.

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Petrel Resampling 2D lines into a 3D Grid P. 5 OF 8

This will result in the first entry you see under your Final folder, an appended polyline at desired resolution.

The blue plane below is actually a series of lines generated based on the seismic layout.

3. Use the operations to assign values from seismic

The next step is to create a point set from these appended polygons, which can be done manually by right-clicking on polylines and using context menu to Convert to Points. It is then necessary to use the Operation tab to assign values from a seismic cube to take the attribute (in this case amplitude) values from your seismic line and assign them to the point set. This has also been written into the workflow for convenience, all that is necessary as an input is to drop in the seismic line (in this case slb1).

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Petrel Resampling 2D lines into a 3D Grid P. 6 OF 8

This will generate the point set in the Final folder, with an attribute called slb1. You can see the point set below, and as we sampled to the seismic resolution the extent and values preserved are the same as the original 2D line.

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Petrel Resampling 2D lines into a 3D Grid P. 7 OF 8

Below we can see the point set (annotated spheres) have been given a value depending on the amplitude of seismic line slb1, which is displayed behind the points with no interpolation so each pixel can be seen definitively.

4. Upscale point set to 3D Grid

The last step is to upscale the point set to the 3D grid. Choose the Scale up well logs process under Property Modeling in your Processes Pane.

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Petrel Resampling 2D lines into a 3D Grid P. 8 OF 8

Then choose to upscale the point attribute you created, making sure to select the seismic attribute.

This will result in a seismic property in your 3D grid for that line. This general workflow can be repeated for many 2D lines, with a property generated for each line. This can then be combined as desired into one property. However it is important to remember to balance/scale any different vintages of 2D lines if you want to compare the amplitude values in the one property. In addition lines must be mistied prior to the workflow, and for intersecting lines a choice must be made on which values to keep for the intersecting cells when you are merging the properties (hopefully a thorough mistie workflow will minimize difference on intersection lines in area of interest).