Method for deriving 3D output volumes using filters derived from flat spot direction vectors

Computer instructions on a computer readable media, comprising instructions to cause a processor to determine the existence of and location of hydrocarbon and water fluid contacts by analyzing spatial changes in 3D seismic data comprising the steps of:

• a) obtaining seismic attribute data as a 3D data volume;
• b) obtain 3D dip and azimuth data as at least one set of 3D volume data and deriving corresponding 3D reliability volumes or deriving corresponding 3D censor volumes which are representative of portions of the at least one set of 3D volume data which 3D dip data and azimuth data can be reliably determined;
• c) selecting a focused subvolume of interest within the at least one set of 3D volume data;
• d) determining reliability locations within the focused subvolume of interest having non-null 3D dip data and non-null 3D azimuth data within the 3D reliability volumes or 3D censor volumes across the focused subvolume of interest forming a sequence of reliability locations;
• e) computing an average for a plurality of vector dips around each reliability location in the sequence of the reliability location forming at least one structural dip vector for each reliability location;
• f) determining a flat spot direction vector for each structural dip vector at each reliability location;
• g) deriving and using a 3D filter with at least one filter length in each direction of the 3D data volume to suppress seismic attribute data that is not parallel to the determined flat spot direction vector around each reliability location to provide filtered 3D seismic attribute data;
• h) storing the filtered 3D seismic attribute data forming a 3D output subvolume;
• and repeating the method for all 3D volume data forming a 3D output volume.