1、Seismic Domain ConversionObjectives Quality control time/depth relationships for wells Define velocity model intervals Create an uncorrected velocity model using well data Create a final corrected velocity model using well data Create a velocity model with uncertainty Depth convert a 3D Grid General

2、 depth conversion Optional: Create a velocity model using a seismic velocity cube Create velocity model using stacking velocities (xytv point-data)Overview Velocity Modeling is separate from Domain Conversion Interactively switch between time and depth for converted objects Define the velocity model

3、 by:-Surfaces/constants-Well Time/Depth Relation-Velocity Cubes-3D grids Convert both ways with the same model Convert objects independent of the 3D grid Perform conversions in the process managerVelocity model bridges the gap between time and depth domainTime domainDepth domainVelocity modelTime -

4、depth conversionDepth - time conversionThe Workflow Define velocity model Define velocity intervals (usually between time interpretation surfaces) Define velocity functions (automatically calculated or user-defined) Define output (e.g. velocity cubes, V0 and k for Q.C. purposes) Domain convert via R

5、ight click on object (uses currently ”active” velocity model) General Depth Conversion Process for Multiple objects 3D Grid Conversion Within a workflow in Process manager The ProcessVelocityCorrectionsZONESOutputAdvancedDatumDatumVoVo + kzVo + k(z-z0)A: Auto 1. Correction (Vo) 2. TDR (Vo & k)B:

6、 User 1. Constant 2. SurfaceC: Velocity SEGY (average)D: 3D Velocity Property (average)DatumVoVo + kzVo + k(z-z0)1. Seg-Y 2. Velocity Surfaces 3. Well Data Points4. T & V logs 5. Residual Points 6. Output Sheet1. Constant 2. Surface3. Horizon*4. Well Tops1. Constant 2. Surface3. Horizon*Or none1

7、. Well trace Md inc 2. Depth & Time tolerance3. Velocity & k clippingAdditional Settings +(Gridding & SegY settings)Saved in Model tabThe exercise examplesTime/Depth relationship in wellsVelocity Cube (SEG-Y)Stacking Velocities (Point data)Velocity Model 1Velocity Model 2*Velocity Model

8、3*Active (selected) Velocity ModelDomain Conversion of objects*Optional exercises, see AttachmentsDefine intervals In the Process pane, open the Geophysics folder and double-click on the Make Velocity Model Click the ”Append item in the table” icon as many times as available input objects Change Bot

9、tom Interval to desired type Select the levels to model, from Input or Models tab, click on its name and drop it into the dialog box using the drop in arrow Keep the Correction set to None32451Velocity modeling using well data Select type of velocity model for each interval. When using the Linvel fu

10、nction for modelling, constants, surfaces or Well TDR can be used as input Set V0 to Well TDR Surface/ Constant Set k to Well TDR Surface/ Constant231Velocity modeling - Output Open the Output tab Click on the data types needed as output215. Defines Gridding algorithms for Surfaces and resolution fo

11、r Cubes, Surfaces and Logs.231 Open the Advanced tab. Check that Well velocity tab is open. Possible to set MD increment, depth and time tolerance and clipping parameters for V0 and k.4. Activate Output settings tab4Velocity modeling Advanced settingsVelocity modeling using well data Open Settings f

12、or Wells and go to the Time tab. Select Checkshots, Well Tops or corrected sonic logs as source for time/depth (move the prefered source to the top) Keep the parameters for the velocity model the same as the values shown Click Apply or OK to generate the velocity model123Velocity modeling with uncer

13、tainty Create a new velocity model with Well tops correction, based on the previous velocity model Toggle on Activate uncertainty page icon to insert a Std Dev column under the Velocity model tab and to activate the Uncertainty tab. Fill in appropriate Std Dev. numbers Go to the Uncertainty tab and

14、fill in appropriate Variogram parameters. Toggle on Iconize uncertainty error surface. Click Apply A velocity model containing velocity surfaces with uncertainty built into them is generated Check uncertainty statistics and display the corresponding deterministic and stochastic V0-surfaces231Determi

15、nistic V0-surfaceStochastic V0-surface45Depth convert a 3D grid Make sure the correct 3D Model is active From the Process tab, under Structural Modeling, open Depth Convert 3D Grid Select the appropriate Velocity Model Alternatively change the pillar geometry types for faulted and non-faulted pillar

16、s before Applying A new 3D Model will appear in the Models tab, with the input 3D grid name and an extension DC34251Depth convert Seismic data Make sure the correct Velocity Model is active (Bold name). Right click on the 3D volume and select Depth convert by active velocity model. Alternatively, fr

17、om the Process tab, under Geophysics, open the General Depth Conversion process. Click on the 3D volume name in the Input tab and drop it into the dialog box using the Append selected item to the list icon. Click Apply.3412Attach seismic to active grid Make sure the correct depth converted 3D Model

18、is active From the Input pane, right click on the seismic 3D volume and select Attach Seismic Volume to active Grid Expand the active depth 3D grid under the Model tab, right click on mig.sgy DC and insert InLine and Xline.View the result in a 3D Window123General depth conversion Make sure the correct Velocity Model is active (bold text) From the Input pane, right click on the object to be depth converted and use Depth convert by active velocity model Clicking the + in front of the depth converted object shows the now available time and