RESERVOIR SERVICES

ASSISTING OUR CLIENTS IN THE DEFINITION OF RESERVOIR GEOMETRY, THE DISTRIBUTION OF PHYSICAL PROPERTY CHARACTERISTICS WITHIN A RESERVOIR, AND IN THE CORRELATION OF ALL AVAILABLE DETAILS, ARCIS OFFERS A STATE-OF-THE-ART SUITE OF SEISMIC RESERVOIR CHARACTERIZATION SERVICES.

Curvature volume computation

Coherence volume computation

AVO/LMR analysis

Azimuthal AVO

Thin-bed reflectivity inversion

Impedance inversion

Spectral decomposition

Seismic facies classification

Multi-attribute analysis

Rock physics analysis

2 Km

Coherence attributes Curvature attributesCoherence computes a measure of similarity between adjacent traces. Identification and mapping of channel edges, reefs, faults and fracture systems in 3D volumes becomes so much easier with the coherence volume. Structural and stratigraphic interpretation of seismic data get facilitated by using a coherence volume. Arcis offers coherence computation services based on Energy Ratio algorithm (a modified eigen-decomposition of covariant matrices approach). This algorithm has generated results better than those from the standard semblance as well as eigen-decomposition based algorithms.

Curvature attributes measure the degree of bending of seismic reflections along a surface or in a volume and help to improve interpretation and structural understanding of 3D seismic data volumes. Different curvature attributes identify subtle faults, fractures, and other features better than other attribute applications. Arcis offers volume computation of curvature, together with their spectral estimates.

Reservoir Services

Coherence using semblance without dip-steering option

Horizon slice through the coherence volume

Coherence using Energy Ratio Horizon slice

through the most-positive curvature volume

Horizon slice through the most-negative curvature volume

Color stack of coherence, most-positive curvature, and most-negative curvature

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HIGH

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POS

NEG

POS

LOW

HIGH

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HIGHLOW HIGHLOW

Coherence using semblance

Coherence (Energy Ratio) after PC-filtering

HIGHLOW

HIGHLOW

2 Km2 Km

2 Km

Data courtesy: Arcis Corporation, Calgary

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Multi-spectral estimates of curvatures

Fracture analysis using curvature attributesInterpretation of lineaments corresponding to subtle faults and trends can be carried out on the most-positive or most-negative curvature horizon slices as shown. The interpreted lineaments are then converted into a rose diagram which can be compared with a similar rose diagram available from image logs.

Reservoir Services

NEG

POS

Time slices 1160 ms

Most-positive curvature

Rose Diagram

90270

0

180

Coherence

Most-positive(long-wave)

Most-positive(short-wave)

Interpretation on curvature displays

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Visualization of attributes

Thin-bed reflectivityArcis offers thin-bed reflectivity inversion using a spectral inversion technique that produces ultra-high resolution seismic data that enhances mapping. Thin-bed reflectivity removes the deleterious effects of the seismic wavelet that cause degraded resolution. Thin-bed reflectivity is performed without using well data, requires no a priori model, no interpreted horizons and no assumed reflectivity spectra.

Reservoir Services

A stratal fault skeleton from the most-positive curvature attribute being correlated with seismic data volume in the increasing inline direction as indicated with the white arrow

Strat-cube from the most-positive curvature attribute co-rendered with coherence seen here in a 3D chair view

Strat-cube from the most-negative curvature attribute co-rendered with coherence seen here in a 3D chair view

Time slice comparison before (left) and after (right) frequency enhancement

Seismic

Input seismic Reflectivity convolved with bandpass wavelet

Reflectivity

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Correction for spurious phase via estimation of non-minimum phase wavelet Rock physics analysis

For a better understanding of lithology and fluid differentiation, Arcis emphasizes the importance of rock physics analysis and integrating that with the AVO/LMR processing flow. Arcis uses an informative and straight forward approach to exhibit the elastic and petrophysical properties of reservoir rocks.

Deconvolution with minimum phase wavelet assumption usually leaves the data with spurious phase. The phase correction required to remove the spurious phase is done by a simple parameterization of the underlying mixed phase wavelet, which involves estimation of an all-pass operator coefficients via cumulant matching technique. The approach involves setting up a cost function with unknown shape and using a simulated annealing algorithm for optimization.

Reservoir Services

Original data Phase corrected data

Original data. The inserted curve is the P-velocity log

Phase corrected data. The inserted curve is the P-velocity log

Vp against Vs

P-impedance against S-impedance

Lambda-Rho against Mu-Rho

Vp against Vp/Vs

Vp against Poisson’s ratio

Lambda-Rho against Lambda/Mu

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AVO/LMR analysis

Seismic/VSP modelingArcis has the capability and innovativeness to accomplish AVO/LMR analysis including AVO friendly processing, QC and interpretation.

Reservoir Services

Overlay of angle information on offset gathers

Lambda-Rho

Mu-Rho

Input gathers Reconstructed gathers Difference

NEG

POS

LOW HIGH

3D Cross-plotting of Lambda-Rho, Mu-Rho and Fluid Stack. Clusters associated with gas anomalies (yellow) separated out

Velocity model

Shot record

Snapshots of the propagating wavefront

m/sec

Velocity model derived from well log

Shot record velocity model with 20 m segmentation interval

Shot record velocity model with 5 m segmentation interval

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Geobody tracking and volume estimationSpectral decomposition

Seismic facies classificationSeismic waveforms in the broad zone of interest are categorized and related to different depositional facies. Arcis offers both unsupervised (statistical) as well as neural network (deterministic) methods for arriving at meaningful and convincing facies analysis.

Spectral decomposition allows utilization of the discrete frequency components of the seismic bandwidth to interpret and understand the subtle details of subsurface stratigraphy. Besides the traditional Fourier transform, Arcis offers the CWT (Continuous Watvelet Transform), Matching Pursuit Decomposition (MPD) and Exponential Pursuit Decomposition (EPD) methods for transformation of data to frequency domain. The latter two techniques offer more accurate analysis.

Geobodies corresponding to porous sandstone accumulations, or the channel-fill within drainage system, or a salt body can be tracked by selecting an amplitude or attribute value as a ‘seed.’ Some of these tracked geobodies help in the assessment of hydrocarbon reserves in place in a given prospect.

Reservoir Services

Phase corrected data

High porosity zone shown tracked by using the ‘seed’ shown in red

Horizon slice at 70 Hz showing channel features with their enhanced definition

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Impedance inversionSeveral different methodologies are available for performing acoustic inversion.• Recursive• Model-based• Sparse-spike• Simultaneous inversion

Multi-attribute analysis Arcis offers neural network or cubic-b spline based multi-attribute analysis. Such an analysis is beneficial if the 3D volume has a reasonably good well control and the wells are representative of the geology in a lateral sense. Application of Probabilistic Neural Network (PNN) to estimate the P-impedance volume provides more detailed information compared to the conventional model-based P-impedance inversion. As seen in the examples below, the PNN application for acoustic impedance shows better correlation with the impedance log than the conventional P-impedance inversion.

P-impedance obtained from post-stack inversion. The inserted black curve is the P-impedance log

P-impedance estimated with probabilistic neural network. The inserted black curve is the P-impedance log

Impedance(m/s² g/cc)

Arcis offers the energy industry a unique, integrated complement

of seismic services including participation “spec” surveys, data

processing, data marketing, geotechnical services and access

to an extensive data library. Arcis offers one of the most current

seismic data libraries of predominantly 3D for the Western

Canadian Sedimentary Basin, including North East British

Columbia. We are committed to exceptional customer service,

superior data quality, innovation, and integrity; while maintaining a

focus on health, safety, and environmental stewardship.

We think different. We think seismic.

www.arcis.com Reservoir Services

2600, 111 - 5TH Avenue SW Calgary, Alberta, Canada T2P 3Y6 403.781.1700 or 888.269.6840 www.arcis.com