Attributes Table

Abbreviations:

  • OS = Open Source
  • OD = OpendTect
  • DS = Dip-Steering
  • NN = Neural Networks
  • HC = HorizonCube
  • FF = Faults and Fractures
  • FCF = Fluid Contact Finder
  • SCI = Seismic Colored Inversion
  • SSB = Seismic Spectral Bluing
  • SFE = Seismic Feature Enhancement
  • DI = Deterministic Inversion
  • MPSI = Multi-Point Stochastic Inversion
  • DHI = Direct Hydrocarbon Indicator
  • QI = Quantitative Interpretation

Note: Some attributes such as Similarity have open source and commercial versions. Detailed information about the Open Source version is given in the attribute name link while more information about the commercial version can be found under the Dip-Steered attribute name link.

Amplitude-based

Attributes

Information

Energy

  • Description: sum of Amplitudes Squared in a time-gate
  • Plugin: OS, OD
  • Stratigraphic: highlights packages with different reflection strengths
  • Siliciclastics: energy may correlate with lithology & porosity
  • Fluids: enhances Bright Spots
  • Other: use Sqrt output option to control output dynamic range
  • References

Scaling

  • Description: various functions to correct amplitudes vs. time
  • Plugin: OS, OD
  • Structural: scaling can be tuned to facilitate structural interpretation
  • Fluids: AGC time-gates smaller than 500ms should be avoided in quantitative interpretation
  • Other: do not apply in workflows that require preservation of original amplitudes
  • References

Event

  • Description: quantifies the shape of an event or relative distance between events
  • Plugin: OS, OD
  • Structural: useful to determine horizon quality
  • Stratigraphic: useful inputs for 3D NN facies classifications
  • References

Stratal Amplitude

  • Description: returns statistical property (min, max, sum etc.) of an attribute in an interval defined along one horizon or between two horizons
  • Plugin: OS, OD
  • Stratigraphic: useful to characterize intervals
  • References

Frequency-based

Attributes

Information

Frequency

  • Description: returns a characteristic feature of an amplitude spectrum
  • Plugin: OS, OD
  • Stratigraphic: useful inputs for 3D NN facies classifications
  • Fluids: Frequency Slope Fall may pick up frequency loss below HC reservoirs
  • Other: Sweetness = RMS Energy / Average Freq. (construct with mathematics) may highlight hydrocarbons and thick sands
  • References

Instantaneous

  • Description: returns Instantaneous Attributes (amplitude, phase, frequency, and derivatives)
  • Plugin: OS, OD
  • Stratigraphic: Amp. useful for sequence boundaries and thin bed tuning; Phase for pinch-outs, sequence boundaries,lapout patterns
  • Siliciclastics: Amp. correlates with lithology & porosity
  • Carbonates: Freq. indicator for fractured zones which show up as low frequency anomalies
  • Fluids: Freq. picks up HC associated low frequency anomalies; Amp. picks up bright spots
  • References

Spectral Decomposition

  • Description: decomposes a trace segment into frequency components (FFT) or Wavelet coefficients (CWT)
  • Plugin: OS, OD
  • Stratigraphic: picks-up thickness variations below seismic resolution caused by tuning; visualized on RGB(A) color-blended horizons; Useful inputs for 3D NN facies classifications
  • Siliciclastics: useful in analysis of channel systems and turbidites using seismic geomorphology
  • Fluids: hydrocarbons may have a distinctive frequency signature. Gas anomalies typically associated with low frequency components
  • Noise: can be used to obtain information at high frequencies not normally believed to be useful
  • Other: where there is a strong hydrocarbon signature masking the underlying geology the hydrocarbon signature may not be present at certain frequencies. These frequencies can be used to map geology
  • References

Multi-trace Attributes

Attributes

Information

Similarity

  • Description: returns a value indicating how much two or more trace segments look alike
  • Plugin: OS, (DS)
  • Structural: visualize faults, salt edges
  • Stratigraphic: visualize abrupt pinch-outs ; erosional incisions; lateral variable lithofacies
  • Siliciclastics: visualize channels, point bar and barrier bar edges, can be used to identify mudflows from internal geometry
  • Carbonates: visualize reef edges, karst features, fracture zones
  • Other: Dip-steered Similarity is superior in dipping strata
  • References

Thinned Fault Likelihood

  • Description: returns the likelihood (0 and 1) of being a fault; Horizontal width is collapsed by thinning to one sample
  • Plugin: FF
  • Structural: visualize faults
  • Carbonates: visualize fracture zones when used as input to fracture density and fracture proximity attributes
  • Other: input for automated fault plane extraction and un-faulting
  • References

Semblance

  • Description: returns semblance coefficient which is a meassure of multichannel coherence
  • Structural: visualize faults, salt edges
  • Stratigraphic: visualize abrupt pinch-outs; erosional incisions; lateral variable lithofacies
  • Ciliciclastics: visualize channels, point bar and barrier bar edges, can be used to identify mudflows form internal geometry
  • Carbonates: visualize reef edges, karst features, fracture zones
  • References

Volume Statistics

  • Description: generic attribute returns a statistical property from a volume of data points
  • Plugin: OS, (DS)
  • Structural: core attribute in various user-defined filters, e.g. dip-steered median filter
  • References

Texture

  • Description: family of GLCM texture attributes from image processing to capture roughness / smoothness of the seismic response
  • Plugin: OS, (DS)
  • Stratigraphic: useful to capture variations in seismic facies either as stand-alone attributes, or as input to UVQ networks
  • Ciliciclastics: visualize channels, lobes, slumps, flood plains etc.
  • Carbonates: visualize reefs, platforms, karsts, etc.
  • Other: Dip-steered Texture attributes should honor stratigraphy better than non dip-steered texture; Image anisotropy can be studied in all 13 possible directions
  • References

Fracture

  • Description: set of attributes to compute fracture properties
  • Plugin: OS, OD
  • Structural: helps in directly visualizing fracture properties from an input fracture-related discontinuity volume, such as curvature, similarity, semblance, texture etc.
  • Carbonates: characterize distance to the nearest fracture and proximity of individual fractures, as well as their density in a given area
  • Fluids: proximity attribute may also be used to visualize the distance to the nearest DHI (e.g. a bright spot) defined on the basis of a simple seismic amplitude cutoff
  • References

Fault Extraction

  • Description: automated fault extraction work flow based on finger vein recognition algorithm (Start from Processing menu, or Volume Builder!)
  • Plugin: OS, DS
  • Structural: visualize faults score volumes and fault-orientations; extract fault sticks, or fault planes
  • References

Impedance-based

Attributes

Information

Absolute Acoustic Impedance

  • Description: model-driven deterministic inversion with stochastic add-on to evaluate uncertainties
  • Plugin: DI, MPSI
  • Stratigraphic: Impedance is a layer property, tuning-effects are removed, pinch-outs are better visible
  • Siliciclastics: AI often correlates with lithology, porosity and pore-fill; Absolute impedance values are a prerequisite in quantitative rock-property predictions; input to quantitative NNs
  • Carbonates: relation between AI and lithology, porosity and pore-fill is more variable and needs to be assessed on case by case basis
  • Fluids: contacts may stand out better; pore-fill prediction is often possible
  • Noise: inverted data contains less random noise
  • Other: AI may be used for net pay estimation and assessing reservoir connectivity ; in presence of thin layers this is best done using the stochastic add-on
  • References

Relative Acoustic Impedance

  • Description: fast, band-limited Acoustic Impedance approach that optimally inverts data by globally honoring well information
  • Plugin: SCI
  • Stratigraphic: facilitates interpretation in geologic layers as opposed to interfaces
  • Siliciclastics: facilitates discrimination between hard and soft layers
  • Carbonates: may pick up high-porosity sweet-spots in tight carbonate reservoirs
  • Fluids: highlights contacts and DHI’s
  • Noise: high-frequency noise is reduced
  • Other: advantage: no exact well tie needed; With SNP plugin Net Sand or Net Pay can be mapped
  • References

Seismic Net Pay

  • Description: computes Net Pay or Net Sand from SCI input and top and bottom reservoir horizons
  • Plugin: SCI, SNP
  • Siliciclastics: designed for siliciclastic settings with relatively thin reservoirs
  • References

Extended Elastic Impedance

  • Description: inverts angle stack data to EEI; Target EEI well logs can be created in OD from Density, P-Sonic and S-Sonic
  • Plugin: DI, MPSI, SCI
  • Fluids: used to incorporate pre-stack information in QI work flows for better separation of lithologies and fluids
  • Noise: may help separate true and false DHI anomalies
  • References

Dip & Azimuth-based

Attributes

Information

Dip

  • Description: computes dips in various directions and azimuth from a SteeringCube that stores inline - and crossline dip
  • Plugin: DS
  • Structural: Polar dip is useful in fault interpretation; Apparent dip highlights faults in specified azimuth direction
  • Stratigraphic: incisions and undulations can be emphasized calculating a lateral gradient of the dip; angular unconformeties can be visualized calculating the vertical gradient of the dip
  • Other: taking gradients (convolve attribute) from the dip often enhances interpretability; apply the volume statistics - variance attribute to the dip gives a measure of chaos
  • References

Curvature

  • Description: group of attributes derived from a SteeringCube that return how curved the dip field is
  • Plugin: DS
  • Structural: highlights faults and fracture zones, local morphologies (bowl, valley, ridge, dome). In extensional settings high curvature-density is an indicator for high fracture-density. In compressional settings high fracture-density occurs in flat areas with low curvature-density
  • Siliciclastics: might be used to detect differentially compacted features such as sand vs clay filled channels ; detects erosional incisions
  • Carbonates: useful to pick reef edges, karst features, identification of fractured zones
  • Fluids: possible usage in fluid flow patterns
  • References

Processing & Filters

Attributes

Information

Mathematics

  • Description: attribute that returns the output of a user-defined formula, or logical expression
  • Plugin: OS, OD
  • Other: used in many filters; complex chains of attributes can be computed; Supports Recursive filters (e.g. in Evaluate Attributes - default set)
  • References

Dip-Steered Median Filter

  • Description: edge-preserving smoothing filter; enhances laterally continuous events; removes random noise; default attribute set
  • Plugin: DS
  • Structural: facilitates structural interpretation, improves auto-tracker performance
  • Noise: removes random noise without smearing spikes
  • Other: amplitude and edge preserving
  • References

Dip-Steered Diffusion Filter

  • Description: sharpens faults in seismic data; Pre-processing step for fault attributes, e.g. Similarity; default attribute set
  • Plugin: DS
  • Structural: facilitates structural interpretation; should not be used in QI because amplitudes are shifted laterally
  • Other: creates artifacts, best used as intermediate step to Fault Enhancement Filter
  • References

Fault Enhancement Filter

  • Description: evaluates the quality of the seismic data from Similarity; applies dip-steered median filter in good-quality data and a dip-steered diffusion filter in bad data zones (around faults); default attribute set
  • Plugin: DS
  • Structural: facilitates structural interpretation; sharpens the edges near discontinuities (faults), while smoothing else where; output has sharper faults and higher contrast between signal and background
  • Stratigraphic: erosional incisions are also enhanced
  • References

Smoothing

  • Description: Structurally Oriented Filter that heavily smooths seismic without smearing across faults. Takes Thinned Fault Likelihood attribute as input
  • Plugin: FF
  • Structural: facilitates structural interpretation; generates seismic with razor sharp edges
  • References

Seismic Spectral Blueing

  • Description: attribute that balances the seismic amplitudes within the bandwidth to match the well reflectivity spectrum
  • Plugin: SSB
  • Structural: small scale faults get better imaged
  • Noise: can create “ringing” if incorrectly applied
  • Other: makes the amplitude spectrum “blue”: high frequencies have more energy that low energies
  • References

Ridge Enhancement Filter

  • Description: sharpens ridges in a Similarity cube; Filter compares three neighboring similarity values in four different time-slice directions and outputs the largest ridge value; improves resolution
  • Plugin: OS, OD
  • Structural: facilitates structural interpretation
  • Other: be aware of side lobes, clip at zero
  • References

Frequency Filter

  • Description: lowpass, Highpass and Bandpass FFT, or Butterworth filters
  • Plugin: OS, OD
  • Structural: facilitates structural interpretation
  • Noise: useful to remove frequency-related noise
  • References

Convolve

  • Description: group of filters that return the output of a convolution; Lowpass removes high frequencies and smooths the data; Laplacian is an edge-preserving filter; Prewitt returns the gradient which is used to enhance contrasts; Wavelet convolves the data with a wavelet
  • Plugin: OS, OD
  • Structural: facilitates structural interpretation
  • Other: often used to enhance other attributes such as dip, similarity or curvature
  • References

GapDecon

  • Description: removes multiples from minimum-phase data with an inverse filter that aims to attenuate a user-defined part of the auto-correlation function; convert to minimum-phase: see Evaluate Attributes default set
  • Plugin: OS, OD
  • Structural: facilitates structural interpretation when multiples interfere with target horizons
  • Stratigraphic: facilitates stratigraphic interpretation in intervals contaminated with multiples
  • Other: GapDecon becomes a Whitening filter (=Spiking deconvolution) with lag=0
  • References

Velocity Fan Filter

  • Description: 3D filter to pass, or suppress energy with apparent velocities (Time surveys) or apparent dips (Depth surveys)
  • Plugin: OS, OD
  • Structural: useful e.g. to suppress flat multiples obscuring dipping primaries
  • Noise: can be tuned to suppress coherent noise with specific velocity (/ dip)
  • References

Match Delta & Delta Resample

  • Description: two attributes that together enable residual alignment of seismic volumes; Match Delta computes vertical shifts that are applied in Delta Resample
  • Plugin: OS, OD
  • Structural: residual alignment of multi-azimuth stacks, or NMO sub-stack before final stacking
  • Fluids: Residual alignment of Time-lapse volumes in 4D studies
  • Other: Can also be used to align sub stacks prior to avo calculations
  • References

Position

  • Description: returns any attribute calculated at the location where another attribute has its minimum, maximum or median within a small volume
  • Plugin: OS, OD
  • Other: Position is the key attribute in the design of a dip-steered diffusion filter
  • References

Reference Shift

  • Description: moves the evaluation position in 3D space; can be used to return Amplitude at [0,0]
  • Plugin: OS, OD
  • Other: powerful combination with mathematics for designing special filters (e.g. ridge-enhancement)
  • References

Fluid Contact Finder

  • Description: stacks amplitudes along depth contour lines to enhance possible hydrocarbon effects
  • Plugin: FCF
  • Fluids: enhances flat-spots and amplitude anomalies; pinpoints fluid contacts; powerful tool in exploration & appraisal to investigate untested blocks
  • Other: FCF pre-stack option enhances AVO effects; local FCF enhances 4D fluid-related effects
  • References

Seismic Feature Enhancement

  • Description: stacks traces along and across random lines to enhance flat-spots
  • Plugin: SFE
  • Fluids: enhances flat-spots and amplitude anomalies in channels
  • References

Meta-attributes

Attributes

Information

ChimneyCube

  • Description: highlights vertical disturbances in seismic data; Used in hydrocarbon migration path mapping and geohazard interpretation
  • Plugin: DS, NN
  • Structural: can discriminate active (vertically leaking) against passive (vertically sealing) faults
  • Siliciclastics: onset of chimneys may indicate source rock
  • Carbonates: highlights Thermobaric fluid paths (secondary porosity); associated A-shapes indicate porosity decrease, V-shapes indicate karstification/increase
  • Fluids: gas chimney can derisk DHIs for low hydrocarbon saturation; positively identify hydrocarbon expulsion, migration and reservoir charge; predict oil vs gas phase reservoirs
  • References

FaultCube

  • Description: highlights major faults
  • Plugin: DS, NN
  • Structural: facilitates mapping of the structural framework
  • Other: user can chose between two input attribute sets; standard and advanced
  • References

SaltCube

  • Description: highlights salt bodies
  • Plugin: DS, NN
  • Structural: helpful in mapping the edges of salt domes
  • References

SlumpCube

  • Description: highlights slumped deposits
  • Plugin: DS, NN
  • Stratigraphic: mapping of slumps and turbidites
  • References

Fingerprint

  • Description: returns how similar the seismic response is to the response at user-defined locations; response is captured by user-defined attributes
  • Plugin: OS, OD
  • Siliciclastics: useful to find similar good reservoirs as encountered in certain wells
  • Carbonates: useful to find similar good reservoirs as encountered in certain wells
  • Fluids: find similar responses as those at known oil and gas locations
  • References

UVQ Waveform

  • Description: clustering of seismic trace segments around a mapped horizon; available as Quick UVQ from horizon tree-menu
  • Plugin: NN
  • Stratigraphic: shows patterns in the interval that are associated with stratigraphy
  • Siliciclastics: picks up channels, lobes, levees, bars, etc.
  • Carbonates: picks up reefs, platforms, barriers, ramps, tidal flats etc.
  • Other: UVQ network can also output 3D volumes; Input attributes should then be phase-independent (no waveforms)
  • References

NN Classification

  • Description: Supervised Neural Network Classification
  • Plugin: NN
  • Stratigraphic: alternative to UVQ; Difference is that patterns represent stratigraphic features the network was trained to recognize
  • Siliciclastics: classification of: good vs bad reservoirs; sands/silts/shales etc.
  • Carbonates: classification of: good vs bad reservoirs; reef/fore-reef/back-reef etc.
  • Fluids: classification of: gas/oil/brine
  • Other: target well logs can be real, or simulated with the SynthRock plugin
  • References

NN Rock Property

  • Description: Rock Properties predicted by MLP network that was trained on target well logs and impedance & seismic input volumes
  • Plugin: NN
  • Siliciclastics: AI often relates to porosity and fluids. Vshale, Gamma-ray usually requires additional pre-stack input
  • Carbonates: Porosity from AI is typically feasible
  • Fluids: Sw prediction may be possible with Acoustic Impedance, Elastic Impedance and Density inputs
  • Other: target well logs can be real, or simulated with the SynthRock plugin
  • References

HorizonCube & SSIS-based

Attributes

Information

Systems Tracts ID

  • Description: assigns a unique ID to interpreted systems tracts for mathematical manipulations and visualization
  • Plugin: HC, SSIS
  • Stratigraphic: enables volume rendering of interpreted packages
  • Siliciclastics: unravel depositional architecture of channel systems
  • Carbonates: understand reef build-ups, platform architecture
  • References

Systems Tracts Isopach

  • Description: returns the thickness of the systems tract unit; helps to understand how sedimentation filled a basin as a function of geologic time
  • Plugin: HC, SSIS
  • Stratigraphic: used as color-overlay in Wheeler diagrams; enables study of depositional trends and sedimentation rates in space and time
  • References

HorizonCube Density

  • Description: returns the number of horizons in a continuous HorizonCube per time (depth) interval
  • Plugin: HC
  • Stratigraphic: highlights un-conformities and condensed sections
  • Siciliclastics: facilitates systems tracts identification
  • Carbonates: facilitates decomposition of carbonate build-ups
  • References

HorizonCube Thickness

  • Description: returns the thickness (in 2WT or depth) between consecutive horizons in a continuous HorizonCube
  • Plugin: HC
  • Stratigraphic: highlights variations in sedimentation patterns
  • Siciliclastics: useful in identification of un-conformities, condensed sections, pinchouts, slumps
  • Carbonates: highlights internal variations in carbonate build-ups
  • References

Pre-stack Attributes

Attributes

Information

AvO and AvA

  • Description: computes Intercept & Gradient from offset or angle gathers; Derived products from I & G and near-far stacks are available as default attribute sets
  • Plugin: OS, OD
  • Siliciclastics: AvO/AvA analyses works best in loose, unconsolidated sands, but can be applied on more mature sands too (often AVO class I or II); can in select cases also be used for lithological prediction
  • Carbonates: due to the higher and more unpredictable variations of rock properties limited success in carbonates ; review applicability on case by case basis
  • Fluids: Primary DHI
  • Other: well calibration and forward modeling/sensitivity analysis reduces uncertainty; note sine2 axis transformation (4.4.0c and later) needs radians as input
  • References

Statistics

  • Description: returns a statistical property from gathers, e.g. to create (partial) stacks that can serve as input for derived AvO attributes from default attribute set
  • Plugin: OS, OD
  • Structural: re-stacking with new parameters may improve structural image
  • Fluids: primary use is pre-processing for AvO attributes in QI work flows
  • References

Velocity Picking

  • Description: pick NMO or RMO velocities on gathers as input to Pre-Stack Depth Migration
  • Plugin: VMB
  • Structural: structural image is improved in an iterative process of velocity picking, gridding, and seismic migration
  • Other: updated velocities can be used to re-stack gathers
  • References