Petrel官方地震解释培训M7_Depth_Conv.ppt

1、Seismic Domain Conversion Objectives 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 Genera

2、l 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 mo

3、del 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 manager Velocity model bridges the gap between time and depth domain Time domain Depth domain Velocity m

4、odel Time - depth conversion Depth - time conversion The Workflow Define velocity model 1. Define velocity intervals (usually between time interpretation surfaces) 2. Define velocity functions (automatically calculated or user-defined) 3. Define output (e.g. velocity cubes, V0 and k for Q.C. purpose

5、s) Domain convert via 1. Right click on object (uses currently ”active” velocity model) 2. General Depth Conversion Process for Multiple objects 3. 3D Grid Conversion 4. Within a workflow in Process manager The Process Velocity Corrections ZONES Output Advanced Datum Datum Vo Vo + kz Vo + k(z-z0) A:

6、 Auto 1. Correction (Vo) 2. TDR (Vo & k) B: User 1. Constant 2. Surface C: Velocity SEGY (average) D: 3D Velocity Property (average) Datum Vo Vo + kz Vo + k(z-z0) 1. Seg-Y 2. Velocity Surfaces 3. Well Data Points 4. T & V logs 5. Residual Points 6. Output Sheet 1. Constant 2. Surface 3. Horizon* 4.

7、Well Tops 1. Constant 2. Surface 3. Horizon* Or none 1. Well trace Md inc 2. Depth & Time tolerance 3. Velocity & k clipping Additional Settings + (Gridding & SegY settings) Saved in Model tab The exercise examples Time/Depth relationship in wells Velocity Cube (SEG- Y) Stacking Velocities (Point da

8、ta) Velocity Model 1 Velocity Model 2* Velocity Model 3* Active (selected) Velocity Model Domain Conversion of objects *Optional exercises, see Attachments Define intervals 1.In the Process pane, open the Geophysics folder and double-click on the Make Velocity Model 2.Click the ”Append item in the t

9、able” icon as many times as available input objects 3.Change Bottom Interval to desired type 4.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 5.Keep the Correction set to None 3 2 4 5 1 Velocity modeling using well data

10、 1.Select type of velocity model for each interval. When using the Linvel function for modelling, constants, surfaces or Well TDR can be used as input 2.Set V0 to Well TDR Surface/ Constant 3.Set k to Well TDR Surface/ Constant 2 3 1 Velocity modeling - Output 1.Open the Output tab 2.Click on the da

11、ta types needed as output 2 1 5.Defines Gridding algorithms for Surfaces and resolution for Cubes, Surfaces and Logs. 2 3 1 1.Open the Advanced tab. 2.Check that Well velocity tab is open. 3.Possible to set MD increment, depth and time tolerance and clipping parameters for V0 and k. 4.Activate Outpu

12、t settings tab 4 Velocity modeling Advanced settings Velocity modeling using well data 1.Open Settings for 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) 2.Keep the parameters for the velocity model th

13、e same as the values shown 3.Click Apply or OK to generate the velocity model 1 2 3 Velocity modeling with uncertainty 1.Create a new velocity model with Well tops correction, based on the previous velocity model 2.Toggle on Activate uncertainty page icon to insert a Std Dev column under the Velocit

14、y model tab and to activate the Uncertainty tab. Fill in appropriate Std Dev. numbers 3.Go to the Uncertainty tab and fill in appropriate Variogram parameters. Toggle on Iconize uncertainty error surface. Click Apply 4.A velocity model containing velocity surfaces with uncertainty built into them is

15、 generated 5.Check uncertainty statistics and display the corresponding deterministic and stochastic V0- surfaces 2 3 1 Deterministic V0-surface Stochastic V0-surface 4 5 Depth convert a 3D grid 1.Make sure the correct 3D Model is active 2.From the Process tab, under Structural Modeling, open Depth

16、Convert 3D Grid 3.Select the appropriate Velocity Model 4.Alternatively change the pillar geometry types for faulted and non-faulted pillars before Applying 5.A new 3D Model will appear in the Models tab, with the input 3D grid name and an extension DC 3 4 2 5 1 Depth convert Seismic data 1.Make sur

17、e the correct Velocity Model is active (Bold name). 2.Right click on the 3D volume and select Depth convert by active velocity model. 3.Alternatively, from the Process tab, under Geophysics, open the General Depth Conversion process. 4.Click on the 3D volume name in the Input tab and drop it into th

18、e dialog box using the Append selected item to the list icon. Click Apply. 3 4 1 2 Attach seismic to active grid 1.Make sure the correct depth converted 3D Model is active 2.From the Input pane, right click on the seismic 3D volume and select Attach Seismic Volume to active Grid 3.Expand the active

19、depth 3D grid under the Model tab, right click on mig.sgy DC and insert InLine and Xline.View the result in a 3D Window 1 2 3 General depth conversion 1.Make sure the correct Velocity Model is active (bold text) 2.From the Input pane, right click on the object to be depth converted and use Depth convert by active velocity model 3.Clicking the + in front of the depth converted object shows the now available time and d