System and method for fault identification

1. A method for identifying a fault patch from a three-dimensional seismic data volume representing underground earth structures, the method comprising:

in a computing system:

defining an initial active surface, the initial active surface including a plurality of control points each in an initial position in the seismic data volume;

computing a plurality of accumulation energy functions for the plurality of control points, wherein each accumulation energy function measures the energy associated with the plurality of control points each positioned in one of a plurality of different candidate positions associated with that control point, wherein computing comprises for the plurality of control points and for the plurality of candidate positions associated with each control point, measuring the accumulation energy functions of the combinations of each of the plurality of control points in each of the candidate positions associated therewith and each of the other of the plurality of control points in each of the candidate positions associated therewith; and

producing the fault patch formed by the plurality of control points in the associated candidate positions for which a minimum accumulated energy is measured.

2. The method of claim 1 , wherein each candidate position defines a different displacement of a control point in a direction that is normal to initial active surface.

3. The method of claim 1 , wherein each accumulated energy function includes a measure of an internal energy of the active surface calculated based on distances between the plurality of control points in the surface.

4. The method of claim 1 , wherein a plurality of control points forming the fault patch are obtained by, starting from one combination of candidate positions, tracking back through a plurality of other combinations of candidate positions and forming the fault patch using the control points in the combination of candidate positions for which a minimum accumulated energy is measured.

5. The method of claim 1 , wherein the accumulated energy function is measured as a function of the local curvature of the active surface.

6. The method of claim 1 , wherein the initial surface is constructed by interpolating a plurality of fault lineaments to produce a set of control points that form the initial surface.

7. The method of claim 1 , comprising:

extracting faultiness sections from the seismic data volume of a faultiness type to obtain faultiness values; and

using the faultiness values to minimize the accumulation energy function.

8. The method of claim 1 , further comprising:

computing faultiness sections from the seismic data volume of a continuity type to obtain faultiness values; and

using the faultiness values to minimize the accumulation energy function.

9. The method of claim 1 , further comprising:

computing a continuity attribute from the seismic data volume of a post-stack amplitude type;

computing faultiness sections from the continuity attribute computed to obtain faultiness values; and

using the faultiness values to minimize the accumulation energy function.

10. The method of claim 1 , further comprising:

applying a combination of low-pass and high-pass filters to filter seismic data from the seismic data volume of post-stack amplitude type.

11. A system for identifying a fault patch from a three-dimensional seismic data volume representing underground earth structures, the system comprising:

a seismic data volume;

a processor configured to define an initial active surface, the initial active surface including a plurality of control points each in an initial position in the seismic data volume,

to compute a plurality of accumulation energy functions for the plurality of control points, wherein each accumulation energy function measures the energy associated with the plurality of control points each positioned in one of a plurality of different candidate positions associated with that control point, wherein when the processor computes, the processor is configured to, for the plurality of control points and for the plurality of candidate positions associated with each control point, measure the accumulation energy functions of the combinations of each of the plurality of control points in each of the candidate positions associated therewith and each of the other of the plurality of control points in each of the candidate positions associated therewith, and

to produce the fault patch formed by the plurality of control points in the associated candidate positions for which a minimum accumulated energy is measured.

12. The system of claim 11 , wherein each candidate position defines a different displacement of a control point in a direction that is normal to initial active surface.

13. The system of claim 11 , wherein each accumulated energy function includes a measure of an internal energy of the active surface calculated based on distances between the plurality of control points in the surface.

14. The system of claim 11 , wherein the processor is configured to obtain a plurality of control points forming the fault patch by, starting from one combination of candidate positions, track back through a plurality of other combinations of candidate positions and form the fault patch using the control points in the combination of candidate positions for which a minimum accumulated energy is measured.

15. The system of claim 11 , wherein the processor is configured to measure the accumulated energy function as a function of the local curvature of the active surface.

16. The system of claim 11 , wherein the processor is configured to construct the initial surface by interpolating a plurality of fault lineaments to produce a set of control points that form the initial surface.

17. The system of claim 11 , wherein the processor is configured to extract faultiness sections from the seismic data volume of a faultiness type to obtain faultiness values used to minimize the accumulation energy function.

18. The system of claim 11 , wherein the processor is configured to compute faultiness sections from the seismic data volume of a continuity type to obtain faultiness values used to minimize the accumulation energy function.

19. The system of claim 11 , wherein the processor is configured to compute a continuity attribute from the seismic data volume of a post-stack amplitude type and compute faultiness sections from the continuity attribute computed to obtain faultiness values used to minimize the accumulation energy function.

20. The system of claim 11 , further comprising a display to display the produced fault patch.