Predicting rock properties from seismic data is one of the pillars of dGB. In 1995 we started out as a QI (Quantitative Interpretation) specialist company offering unique work flows based on stochastic forward modeling of pseudo-wells and non-linear (neural network-based) predictions. Since then we have broadened our services portfolio considerably, but our passion for QI projects remains. We offer rock-physics analysis, AvO attribute analysis, forward modeling of synthetic data, seismic inversion products, rock-property predictions and integrated interpretation services.
OpendTect Inversion & Rock Properties Package is the main toolkit we use in these projects. This package provides a wide range of tools for innovative QI work. A unique work flow is the HitCube inversion approach supported in SynthRock. In this work flow a stochastic simulator generates thousands of 1D models (pseudo-wells). In a HitCube run the synthetics of these pseudo-wells are cross-matched against the real seismic data. This results in 3D probability (expectation & standard deviation) volumes of rock-properties of interest.
Understanding geology is the key to drilling successful wells. This means that one needs to gain understanding in the 3D distribution of lithologies, rock properties and fluid fill in the subsurface. Predicting these distributions from 3D seismic data with control points at well locations is the current industry standard. At dGB we take reservoir prediction a step further by looking beyond the numbers and use geological models to improve our prediction. Also, with the use of neural networks, we avoid using oversimplified linear models which can not accurately describe most rock property relations.
Overview of reservoir characterization services:
- Log-log predictions
- Lithology clustering
- Pattern analysis (Markov chain)
- Sensitivity modeling
- Stochastic pseudo-well modeling
- AVO analysis, rock physics.
- Seismic Spectral Blueing
- Clustered/classified seismic
- (Extended Elastic) Impedance inversion
- HorizonCube-based geo-models
- HorizonCube-based low frequency models
- Rock properties prediction.
Forward pseudo-well modeling and probabilistic inversion to achieve qualitative and quantitative seismic interpretation. It includes wedge models, stochastic models, pre- and post-stack synthetic seismograms and cross-matching (HitCube) inversion.
Sophisticated workflows in which model parameters are varied stochastically can be run to create a data base of pseudo-wells, representative of the expected geologic and seismic variations at target level. Such models are then used to predict rock properties with uncertainties from pre- and post-stack seismic volumes.
Read more about the SynthRock plugin
All kind of rock properties can be predicted with the use of the neural networks plugin. It is possible to relate any well log to seismic data. Examples are porosity, Vshale, lithology, permeability.
Read more about the Neural Network plugin
HorizonCube is a game-changing technology that impacts every level of seismic interpretation. A HorizonCube consists of a dense set of correlated 3D stratigraphic surfaces that are assigned a relative geological age. The technology was initially developed for sequence stratigraphic interpretation and as such was part of the SSIS plugin where it was called chronostratigraphy. Because the technology has a much wider application range the HorizonCube became a separate plugin in v.4.2. The HorizonCube can be utilized to build geo-models by interpolating well logs following the many horizons contained in the HorizonCube. Such geo-model can further be used to create low frequency models, necessary input for any model-based inversion.
Read more about the HorizonCube plugin
Deterministic Inversion includes a 3D model builder for the construction of a priori impedance models using well log and seismic horizon data; a 2D error grid generation module to provide spatial inversion constraints and a model-based deterministic acoustic impedance inversion module.
Read more about the Deterministic Inversion plugin
Stochastic Inversion includes the MPSI UltraFast stochastic inversion module for the generation of multiple geostatistical realizations. This plugin allows the user to explore the impact of the geophysical uncertainties in the inversion process. Utilities for post-processing the multiple realizations are available to create expectation, standard deviation, and (joined) probability and trend volumes. This plugin requires a license for the deterministic inversion plugin to be in place.
Read more about the Stochastic Inversion plugin
Seismic Coloured Inversion enables rapid band-limited acoustic impedance inversion of seismic data. A single convolution inversion operator is derived which optimally inverts the data. The spectrum of the inverted data honours the available well data spectra in a global sense. Generally, traditional inversion methods (e.g. sparse-spike) are time consuming, expensive, require specialists and are not performed routinely by the Interpretation Geophysicist, whereas SCI is rapid, easy to use, inexpensive, robust and does not require expert users. SCI and unconstrained sparse-spike appear to give broadly equivalent results.
Read more about the SCI plugin
CLAS Lite is an open-hole log analysis plugin by Sitfal for geoscientists providing tools for different purposes:
Read more about the CLAS Lite plugin