DUG Insight User ManualFrequently Asked QuestionsFrequently Asked Questions HorizonsHow to mark a pinchout/intersection of two surfaces using a polygon?

How to mark a pinchout/intersection of two surfaces using a polygon?

Investigating stratigraphic traps or a stratigraphic surface which has been interrupted by a fault?  How do we map the resultant pinchout/intersection between these two horizons using DUG-Insight?  The workflow below discusses how to create a detailed polygon outlining the pinchout/intersection.


  1. Pick the top (h1) and base (h2) horizons of your pinchout structure 
  2. Create a pinchout horizon using Horizon maths
    • Inputs: h1 = top horizon, h2 = base horizon
    • Formula: if (h1<h2, h1, nan)
    • (If top horizon is greater than base horizon use top horizon.  If not use nan as value.)
  1. Create a constant horizon using the Constant horizon 
    • Value: 0 ms
    • Vertical: TWT
    • Output grid: polygon which covers entire horizon area
    • Spacing: 100
    • Survey: Same 3D survey as original horizons
  1. Merge the pinchout horizon created in step 2 and constant horizon created in step 3 using Horizon Maths
    • Inputs: h1 = pinchout horizon, h2 = constant horizon
    • Formula: merge (h1, h2)
    • (Merge pinchout horizon and constant horizon, give priority to pinchout horizon)
  1. Display in Map View.

We now have the intersection represented clearly on the merged horizon.  Create a polygon along this boundary using create polygon from contours tool.

  1. Open Display tab and select contours
  2. Display 0 contour in Map View
  1. Create polygon from contour 0 using Create contour Polygons
  1. Final polygon showing pinchout intersection.