4D seismic surveys play a vital role in monitoring oil and gas fields. Acquired data provide spatial information regarding changes that occur during the course of production. This information is used to update reservoir simulation models, increase the reliability of production forecasts, and improve field management.
Seismic history matching requires integration of a wide range of subsurface data and a formal, yet flexible workflow to facilitate collaborative decision-making by asset teams. Correlating attribute analysis from successive seismic surveys with well production histories and reservoir models is best accomplished using analytical and visualization software.
The Need for Integration of Discipline-Specific Datasets
The initial challenge regarding seismic history matching is the integration of relevant data associated with producing assets. Multiple software products used to acquire or generate seismic data, production metrics, and reservoir simulations produce a variety of data types and formats. Although these data characterize the same geospatial area of the producing asset, the diversity of data types and formats present barriers to their effective use in seismic history matching.
Visualization and analytic software solutions like CoViz 4D eliminate these barriers via a data registry. Team members—geophysicists, production engineers, and reservoir engineers share relevant data simply via “drag and drop” add their discipline-specific datasets into the data registry. From there, the software automatically manages the conversion and scaling of the data into a format for visualization and analysis using a rich set of quantitative tools and workflows to support seismic history matching.
Flexible, Iterative Workflows and Quantitative Tools
CoViz 4D leads the industry in the visualization of diverse subsurface data used in hydrocarbon asset development. Seismic history matching workflow modules and a selection of qualitative and quantitative tools give reservoir engineers and geophysicists the ability to efficiently analyze, validate, and update reservoir models. CoViz 4D provides pre-built automated workflows and also offers the option to create customized workflows via scripting, Python, and user-created APIs. The following abbreviated example provides a taste of the workflow flexibility and power of analytic tools.
1. From Simulations to Petroelastic Model
The available Sim2Pem module in the CoViz Sim2Seis workflow quickly and easily guides the user from flow/saturation model to petroelastic (velocity and density) model. Some of the available options include:
- Gassmann substitution to create petroelastic models from rock physics parameters
- Krief or polynomial options for expression of dry moduli
- Batzle-Wang or user-provided custom fluid calculations
- Optional accommodation of time-varying porosity
- Rapid interactive QC and scanning of the output attributes
2. From Petroelastic Model to Synthetic Seismic Volume
Generate a 4D synthetic seismic volume that shows expected response and velocity variations based on the petroelastic model. Apply a wide variety of available analytic capabilities for synthetic seismic volume development. Options include:
- Integrated depth-to-time and time-to-depth conversions
- Band-limited impedance or reflectivity volumes
- 4D difference volume outputs
- Multiple intermediate output options for QC
- Workflows for rapid looping and sensitivity analysis
3. Qualitative and Quantitative Comparison
After creating the synthetic seismic volume, conduct the qualitative and quantitative comparison of the synthetic volumes with the field-measured seismic and reservoir simulation input. CoViz 4D provides built-in tools for rapid, integrated, quantitative analysis and statistical comparison of geometrically diverse, yet spatially-overlapping 3D and 4D data sets. Features include:
- Time-step arithmetic operations for rapid calculations of differences over time
- Interactive tools for property averages and attribute extractions in seismic space and cellular space
- Back-interpolations of properties between spatially and temporally overlapping data
- Statistical analysis, including histograms, probability plots, and cross-plotting of diverse data types
- Options to capture and export the results of the quantitative analysis
As comparisons are made, the iterative workflow process supports an efficient feedback loop to compare various models, matching quality for seismic amplitude, identifying the poorest matches, and modifying the simulations to minimize the discrepancies.
Efficient and Accurate Seismic History Matching
CoViz4D gives operators an unsurpassed ability to cross-correlate time-sequenced seismic data with reservoir models to more accurately track fluid migration and identify under- or over-produced locations within a reservoir. Powerful 4D visualization, a comprehensive set of analytic tools, and flexible workflows enable geoscientists and engineers to conduct seismic history matching activities far more efficiently and achieve greater accuracy in results.
CoViz 4D leads the industry in the visualization of diverse subsurface data used in hydrocarbon asset development.