![]() Select a control point in the middle of the survey by double clicking. Notice how a control point in the center of the survey has a denser plot of first break picks than the control point on the edge of the survey.ĩ Refraction Statics – picking velocitiesġ. The selected control point is highlighted in yellow. Double click a control point circle to display the graph of offset versus time in the adjacent window. Change the Model Time Range to 40, this adjusts the width of your velocity picking line. Be sure the number of layers is set to 2. Click the Parameter Options icon this will take us back to the options window that popped up upon opening the window. However, if the majority of a control point circle is off the grid, it will make velocities harder to pick due to less data being included in the control point.ħ Refraction Statics 1. Don’t worry too much about the overlap of control points. Change radius to 1500, and change In-line incr and X-line incr to Click OK Note: You want to cover as much of the shot-receiver layout as possible. Click the add control point(s) icon We will add control points in a grid like fashion instead of one by one. These control points define a model which is the velocity and intercept time for each layer. Click OK Initially the statics window appears as it does above.Ħ Refraction Statics Note: The first step in analyzing refraction statics is setting up control points. For now, these settings are alright, we can change them later. A window appears upon start up with some settings. First break picks Here you can see we are first asking the software to 3. Open up the Elevation/Refraction Statics window by clicking the icon in the main project dataset window. Constant weathering depth.ĥ Refraction Statics 1. ![]() This is theory, in software we do it little differently!!! Assumptions: Elevations of the source and receiver to be approximately the same. Estimate velocity of the refracted event (head wave) Compute ΔT of the weathering zone for each trace. If this is the first arrival after the linear correction should be flat in common shot, common receiver, or common midpoint gather. Hope you remember it from the class!!! Direct wave Refracted wave First break pickĪ simple approach: Assume a refractor to be horizontal. Click and hold save then click save kill picks to data headers 5. Select the kill traces icon on the main seismic toolbar. Refraction Statics Objectives: Upload kill file Define Layer 1 and Layer 2 velocities in refraction statics Pick semblance velocities Bryce Hutchinson & Sumit VermaĢ Upload a kill file 1.
0 Comments
Leave a Reply. |