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GC'Unfolding/Unfaulting' Seismic
Sections Yields New Interpretations*
Kees Rutten1 Search and Discovery Article #40531 (2010) Posted May 14, 2010
*Adapted from the Geophysical Corner column, prepared by the author and editor, in AAPG Explorer, April, 2010, and entitled "'Unfolding' Yields New Interpretations." Editor of Geophysical Corner is Bob A. Hardage ([email protected]). Managing Editor of AAPG Explorer is Vern Stefanic; Larry Nation is Communications Director.
1Slokkert Consultancy, Rolde, Netherlands ([email protected])
A pair of scissors always sat next to the box of colored pencils on Kees Rutten's desk, littered with seismic
sections, time-to-depth curves and well logs. The scissors were used to cut up
seismic
sections and shift the pieces along faults to check correlations and to see the
seismic
-character variation across faults. One of his successful, scissors-generated well proposals was an oil field trapped laterally against a clay-filled slump scar on a shelf edge in the middle of heavy faulting.
On retirement from Shell, Kees started developing software to replace his scissors. The computer enables him to deal with more complex geology than was possible by shifting rigid pieces of paper. Variation of slip along syn-sedimentary faults and topological problems such as branching faults and crossing faults are now done on a workstation. Kees uses the terms "unfaulting" and "unfolding" to distinguish his technology from palinspastic restoration technology that is more suitable for structural geological studies.
Kees is passionate about placing his technology in the hands of seismic
interpreters and has teamed with Halliburton/Landmark to bring it to the desks of mainstream
seismic
interpreters under the name "ezValidator." The two examples in this article speak for themselves: Both sections are from deltaic areas and exhibit growth faults, branching faults and crossing faults. Each section has 15 to 50 stacked reservoir sands filled with oil and gas.
♦Background ♦Figures ♦Examples ♦Conclusions ♦Comments ♦Background ♦Figures ♦Examples ♦Conclusions ♦Comments ♦Background ♦Figures ♦Examples ♦Conclusions ♦Comments |
The first example shows a structure with two large growth faults that are fairly easy to interpret (Figure 1). The structure in the second example (Figure 2) is complex, and even after numerous wells were drilled, the fault pattern remained uncertain, leading to two blow-outs. Using unfaulting technology, a fault The unfaulting algorithm is based on elastic deformation. You can think of a beam passing along the Neither the unfaulting algorithm nor the unfolding algorithm requires information not found in the This real-time interaction contrasts with earlier software that required two-to-five days to massage fault blocks on a section and to establish fault hierarchy, with 30 minutes of CPU time needed for each change. There is an early release of the technology in Landmark's PowerView/ezValidator that can be evaluated. A full release is slated for 2010 in the DecisionSpace Desktop. Kees lost one leg due to thrombosis on a long flight to Houston five years ago, but is still skiing in the Alps and sailing his legendary flat-bottom boat on the mudflats in the north of Holland. He is thinking about a new project using an old
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